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Independent Submission J. Davin
Request for Comments: 7681 October 2015
Category: Informational
ISSN: 2070-1721
Email Exchange of Secondary School Transcripts
Abstract
A common format simplifies exchange of secondary school academic
transcripts via electronic mail. Existing standards are applied to
prevent unauthorized alteration of transcript content and to deliver
transcripts directly and securely from each student to his or her
chosen recipients. By eliminating third-party intervention and
surveillance, the defined protocol better protects student privacy
and independence than does current practice.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7681.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
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RFC 7681 EESST Protocol Specification October 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Design Motivation . . . . . . . . . . . . . . . . . . . . . . 6
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Student and Originator . . . . . . . . . . . . . . . . . 8
3.1.1. Transcript Requests . . . . . . . . . . . . . . . . . 9
3.2. Student and Recipient . . . . . . . . . . . . . . . . . . 10
4. Transcript Content . . . . . . . . . . . . . . . . . . . . . 13
4.1. School Transcript Preface . . . . . . . . . . . . . . . . 17
4.2. Computational School Transcript . . . . . . . . . . . . . 17
4.3. Display School Transcript . . . . . . . . . . . . . . . . 20
5. Signed School Transcript . . . . . . . . . . . . . . . . . . 21
6. Transcript Transmission . . . . . . . . . . . . . . . . . . . 24
6.1. Encrypted Format . . . . . . . . . . . . . . . . . . . . 27
6.2. Encrypted and Signed Format . . . . . . . . . . . . . . . 28
6.3. Encrypted File Format . . . . . . . . . . . . . . . . . . 30
6.4. Traditional Inline Format . . . . . . . . . . . . . . . . 33
7. Security Considerations . . . . . . . . . . . . . . . . . . . 34
7.1. Originator Private Key . . . . . . . . . . . . . . . . . 35
7.2. Originator Public Key . . . . . . . . . . . . . . . . . . 35
7.3. Originator Certification . . . . . . . . . . . . . . . . 35
7.4. Recipient Public Key . . . . . . . . . . . . . . . . . . 35
7.5. Secure Clients . . . . . . . . . . . . . . . . . . . . . 36
7.6. Automatic Replies . . . . . . . . . . . . . . . . . . . . 36
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
8.1. Registration of Eesst-Version Header . . . . . . . . . . 37
8.2. Registration of Organization Header . . . . . . . . . . . 37
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.1. Normative References . . . . . . . . . . . . . . . . . . 38
9.2. Informative References . . . . . . . . . . . . . . . . . 38
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 40
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 40
1. Introduction
Traditional, paper-based communication of individual student records
protects the rights and interests of all stakeholders -- the
secondary school officials who curate student records, the students
who are both the subjects and distributors of their own individual
records, and the college admission officers, prospective employers,
and others who, with the permission of individual students, receive
and review such records. In the traditional process, when a
graduating student applies for employment or admission to an
institution of higher learning, she asks the guidance counselor at
her secondary school for a transcript of her academic achievements to
support her application. In response, the guidance counselor
prepares a paper record of that student's achievements and presents
Davin Informational [Page 2]
RFC 7681 EESST Protocol Specification October 2015
it to her so that she might forward that transcript to whomever she
pleases. In order to prevent forgery of academic transcripts, the
paper record presented to the student often includes various marks of
its authenticity, such as an imprint of the school seal or the
signature of an authorized school official. In order to prevent
unauthorized alteration of transcript content, the prepared document
is sometimes presented to the student inside a sealed postal envelope
that cannot easily be opened without detection -- perhaps aided by
tamper-proof tape, signed envelope flaps, or even imprinted wax
seals. The integrity of the envelope's physical seal assures the
recipient that its contents have not been altered in transit; seals
and signatures affixed to the enclosed document assure the recipient
of the transcript's legitimacy. The student's privacy is assured by
her ability to forward the sealed transcript to whomever she pleases
without the knowledge of or further consultation with the school.
+++
/ \
/\ Digital Transcript / \
/ \ Via Web or Database Connection / \
/ 88 \ / \
/ 88 \ \\ // | College |
/ \ (---) +-------------->> | |
| School | +--------->> (###) +---------+
| | | |
+--------+ <<... | | Copies of Digital Transcript
School Guidance Dept \@| |@ Via Web or Database Connection
| |
+ + +-------+ +++
+------------>> / \
Third-Party Processor / \
Monitors and Controls / \
Student Communication / \
| College |
| |
+---------+
Figure 1: Corrupted Model for Exchanging Secondary School Transcripts
While the traditional process of distributing academic transcripts
admirably protects student privacy and prerogatives, that process
also requires manual effort from the school staff for the preparation
of each transcript. On the premise of reducing that effort, some
school officials have gratuitously misapplied technology in a way
that guts student privacy and effectively excludes students from
their own business. Figure 1 illustrates an increasingly common
aberration. Rather than adopting standardized, readily available
technology to protect the integrity of transmitted student data -- as
Davin Informational [Page 3]
RFC 7681 EESST Protocol Specification October 2015
it had once been protected by their own signatures on sealed
envelopes -- school officials interpose themselves (or their agents)
between students and transcript recipients, claiming falsely that no
other approach adequately assures the confidentiality, origin, and
integrity of transcript content or the reliability of transcript
transmission. By introducing the role of "third-party processor" in
Figure 1, educators disrupt what should be private, bilateral
relationships between students and their chosen correspondents,
implicitly denying the legitimacy of any technical means by which a
student might manage and secure his/her own communication.
By coercing students into a false choice between surrendering their
privacy or accepting the limitations of a neglected, largely manual
system, educators and allied service providers gain significant new
benefits at student expense. Among these benefits is the creation of
an otherwise unneeded educational services industry to mediate
communication between students and transcript recipients --
communication that, by the most natural operation of the Internet,
would otherwise be end-to-end. A second consequence of coerced
mediation is that the mediators gain unfettered control over school
records that would otherwise be private and often protected by law.
A third consequence of coerced mediation is that mediators can
harvest candid data on student behavior outside the secondary school
domain. Even the most basic information about college and employment
applications, successful or not, individual or in the aggregate, can
have significant value for secondary school officials, college
administrators, employers, and general marketing professionals.
Moreover, although such data is historically private, it is also more
valuable and legally less well protected than internal secondary
school records.
Mediated transcript distribution vitiates student privacy while
endowing school bureaucrats and their confederates with undeserved
privilege, but these political concessions are utterly unnecessary to
automated transcript distribution. As suggested by Figure 2, the
political concessions intrinsic to mediated transcript exchange can
be largely eliminated by the most straightforward automation of the
traditional transcript process.
This memo specifies a common format for exchanging secondary school
academic transcripts via electronic mail. Because the defined format
supports digital signature of transcripts by their originator, a
student cannot fabricate or alter transcript information provided by
school officials. Because the described format supports encrypted
transmission of school transcripts, the distribution of each
student's information can remain private and under his or her
control. Because the format supports asymmetric cryptography, the
origin and integrity of received transcripts can be verified
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independently by the recipient; confidential content can be
independently recovered by an intended recipient while remaining
protected from unauthorized access. Because the Internet email
protocol provides fail-safe delivery, transcripts are reliably
delivered to their intended recipients, and the sending student is
directly notified of any exceptions. No centralized, trusted
authority is needed to mediate communication between students,
transcript originators, or transcript recipients. Thus, a student's
need for an authoritative record of his education cannot be exploited
to restrict or monitor his/her free and private interactions with
colleges, employers, or others. Students can reclaim control over
their own personal information and their relationships with
prospective employers and admissions officers; students can prevent
surreptitious harvesting of information about their affairs. Last
but not least, specialized software is not required by most
participants in the school transcript exchange protocol: the needs of
all students and many transcript recipients can be met by existing,
standards-based, secure email clients.
+++
/ \
/\ Digitally Signed Transcript / \
/ \ Via CD-ROM, Secure Email, etc. / \
/ 88 \ / \
/ 88 \ --- | College |
/ \ (0 0) +-------------->> | |
| School | +--------->> ( - ) +---------+
| | | | Copies of
+--------+ | | Digitally Signed Transcript
School Guidance Dept | | Via Secure Email, CD-ROM, etc.
| |
| | +-------+ +++
8 8 +------------>> / \
Student / \
Privately and Autonomously / \
Forwards Digitally Signed Transcript / \
| College |
| |
+---------+
Figure 2: Traditional Model for Exchanging Secondary School
Transcripts
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The acronym EESST (Email Exchange of Secondary School Transcripts)
names the format and methods defined here for securely conveying
student academic records under student control. Requirements for
implementors of this specification are expressed here using a keyword
vocabulary [RFC2119] that is widely understood within the Internet
community.
2. Design Motivation
Implicit in any protocol definition is some assignment of functions
to the various protocol participants. When those participants are
administratively independent one from another, binding assignments of
protocol function -- which might otherwise seem purely technical
choices -- are politically significant. For the sake of
transparency, this protocol specification explicitly reckons the
political consequences of its implicit design choices.
Preparation and delivery of secondary school transcripts most affects
the interests of individual students. After all, the process is
entirely motivated by a student's need to certify his or her personal
academic achievements as evidence of merit for employment, higher
education, or other social advancement or reward. Accordingly,
individual student needs properly dominate the design of a common
system for transcript exchange. Because a secondary school
transcript certifies a student's personal merit, students need
transcript documents that are credible to recipients -- for which the
origin and integrity of transcript content is assured. Because a
school transcript records personal information about an individual
student, student privacy is paramount: control of transcript
distribution must be closely held by the individual student, and each
student must be able to protect the confidentiality of his or her
transcript in transit.
Communication of transcript content between originator, student, and
ultimate recipient is most secure only if that communication is end-
to-end. While the end-to-end argument [Sal84] is fundamental to the
design of the Internet, it is also critical to the design of secure
communication protocols (see Section 6.2 of RFC 1958 [RFC1958]). In
contrast, securely communicating student information to a centralized
(and otherwise uninvolved) third party clearly degrades student
privacy and increases cost. Claims to the contrary are at best
logically absurd and at worst darkly motivated.
After students, transcript handling must address the interests of
transcript recipients, which may include college admission officers,
prospective employers, and scholarship foundations. Recipients must
be able to evaluate the origin and integrity of received transcript
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RFC 7681 EESST Protocol Specification October 2015
documents easily and independently. Secondarily, recipients may
benefit from mechanical extraction and summary of transcript content
to support their own internal decision processes.
Finally, common transcript handling must address the needs of the
transcript originator -- typically a secondary school guidance
counselor or other school official. An originator's legitimate
interests are reducing the cost of preparing transcript documents and
meeting any legal or moral obligations to protect student privacy.
Insofar as the very notion of electronic school transcripts implies
their automated preparation by computers, dramatic cost reductions
over traditional manual processes are also implicit. An originator's
obligation to protect student privacy is most elegantly and
inexpensively met by simply not conveying transcript information
about a particular student to anyone other than that student.
A protocol by which students must request transcript distributions
addresses no actual student need but, rather, only the legal needs of
third parties seeking to intervene in otherwise private
communications. The additional effort of formal transcript requests
is needed only when a mediating third party is involved, because, in
many jurisdictions, sharing personal information with the third party
legally requires student consent, and an electronic transcript
request may be conveniently construed as implicit consent. Moreover,
a formal transcript request-response protocol is not needed to
document delivery of a transcript to its intended recipient. When
the student, rather than a third party, directly conveys his/her
transcript to a chosen recipient, that student has the greatest
interest in successful communication, can observe any communication
failures firsthand, and can take corrective action if needed.
Familiar, standardized protocols provide unambiguous feedback to the
student about successful transcript delivery. The SMTP protocol, in
particular, is defined and implemented to be fail-safe, as described
in Section 4.1.1.4 of its specification [RFC5321]:
Receipt of the end of mail data indication requires the server to
process the stored mail transaction information. This processing
consumes the information in the reverse-path buffer, the forward-
path buffer, and the mail data buffer, and on the completion of
this command these buffers are cleared. If the processing is
successful, the receiver MUST send an OK reply. If the processing
fails, the receiver MUST send a failure reply. The SMTP model
does not allow for partial failures at this point: either the
message is accepted by the server for delivery and a positive
response is returned or it is not accepted and a failure reply is
returned. In sending a positive "250 OK" completion reply to the
end of data indication, the receiver takes full responsibility for
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RFC 7681 EESST Protocol Specification October 2015
the message (see Section 6.1). Errors that are diagnosed
subsequently MUST be reported in a mail message, as discussed in
Section 4.4.
3. Protocol Overview
Existing, standardized technology simplifies the process of preparing
and distributing secondary school transcripts. Using a computerized
procedure, a secondary school administrator prepares a digital
transcript document that records the academic achievements of a
particular student and presents that document to that student. Using
postal delivery, secure email, or other method, the student conveys
digital copies of the prepared transcript to recipients of his or her
choice. Using a computerized procedure, each recipient may
independently verify that the received transcript has not been forged
or altered in transit. Because the received transcript is digital,
each recipient may use computerized procedures to extract and
summarize transcript content for local review and processing.
Preparing and delivering a secondary school transcript entails
interaction among three kinds of participant -- transcript
originator, student, and transcript recipient -- each of whom
performs a distinct functional role. Interactions between each kind
of participant are proscribed below.
3.1. Student and Originator
A transcript originator assembles and digitally signs academic
transcripts that document the achievements of individual students in
a secondary school. The role of transcript originator is frequently
filled by the director of a high-school guidance department or other
secondary school official. At fixed times throughout the school
year, using then-current information from a student database, the
guidance director executes a computer program that, for each relevant
student, automatically creates an individual transcript report and
digitally signs that report on the director's behalf. The format of
each signed transcript document is defined in Section 5 below.
The principal responsibilities of a transcript originator are:
1. Generate an OpenPGP key pair that can be used to sign school
transcripts.
2. Create and securely store a key revocation certificate for the
signing key pair for possible future use should it be
compromised.
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3. Publish on the World Wide Web the public component of the
transcript signing key pair, together with its OpenPGP
fingerprint.
4. Securely store the private component of the signing key pair and
protect its use with a judiciously chosen passphrase known only
to the transcript originator.
5. Use the signing key pair to create and digitally sign transcripts
for individual students.
6. Present each signed transcript confidentially to the individual
student to which it pertains.
Once generated by the transcript originator, each transcript is
conveyed to the relevant student using any means that protects the
confidentiality of individual student data. For example, a digital
transcript may be written to a CD-ROM storage disk and presented to
the relevant student when he comes to school. Alternatively, that
same CD-ROM could be sealed in an envelope and sent to the student
via postal delivery. A student could present a USB flash drive in
person at the school guidance office, and her digital transcript
could be copied onto that drive. A digital school transcript could
also be presented to the relevant student as a MIME attachment to an
email message that is encrypted according to the OpenPGP
specification. When email is used to convey school transcripts to
students, formatting such messages as specified in Section 6 below
will foster security and interoperability.
After a student receives his/her transcript from its originator, that
student is solely responsible for conveying that transcript to any
recipients of his/her choosing, as described in Section 3.2 below.
3.1.1. Transcript Requests
For several reasons, how students request generation of an academic
transcript from their secondary school is a local matter that need
not and ought not be addressed here.
First, the volume of requests for transcripts is likely to be
relatively low, because transcripts can be pre-issued to most
students (e.g., graduating seniors) who are likely to need them.
When transcripts are digital and easily duplicated by the student,
there is no need to generate a new transcript document for each
desired recipient. Accordingly, most transcript generation is driven
not by student requests but rather by content updates arising from
the predictable passing of marking periods or academic sessions
throughout the school year. Thus, explicit requests for transcript
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generation will be the exception rather than the rule -- from
students who have lost a previously issued transcript, or students
leaving the school prior to their graduation.
Second, a historical motivation for formalizing transcript requests
has been to satisfy the school's legal obligation to protect student
privacy. In many legal jurisdictions, school officials are required
to seek student authorization for releasing information to a third
party. Elaborate procedures for requesting transcripts are attempts
to codify or automate that authorization process. However, because,
under the procedure defined here, each student's information is
provided only to that student, no authorization for releasing
information to a third party is required.
Third, a codified transcript request protocol affords almost no
benefit beyond enabling third-party processors to assume the role of
transcript originator and/or distributor. Students need no formal
"acknowledgment" of their transcript requests: the transcript itself
serves that purpose. Because a digital transcript is easily
generated by an automated procedure, there is no benefit to returning
a request acknowledgment rather than the document actually requested.
The primary goal of this protocol design is to strengthen student
privacy and agency by eliminating third-party intrusion into what
would otherwise be private, bilateral interactions between a student
and his school. To codify transcript requests is to undercut
directly that fundamental purpose, while gratuitously restricting
local interactions between student and school.
When each student -- rather than a school official or mediating third
party -- exercises principal control of distributing his or her own
transcript information, any need for transcript requests is largely
obviated. Thus, exchanging and processing such requests is properly
a local matter and not further addressed here.
3.2. Student and Recipient
When a student is asked (e.g., by a college admissions office or
prospective employer) to provide an official transcript of his or her
academic achievements, that student may send to the requesting party
a copy of the digitally signed transcript document that he has
previously received from his secondary school. In this context, the
party requesting that the student send a transcript is called a
transcript recipient. Because it is the student who conveys his own
transcript information, he or she unambiguously controls the set of
recipients, and neither the secondary school nor any third party is
responsible for or privy to the identities of his correspondents.
Similarly, the student is responsible for assuring the privacy of his
or her personal information as he conveys it to these recipients.
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The student may convey his transcript to his chosen recipient using
any mutually agreeable strategy. For example, he may print a copy of
his transcript onto a postcard and send it via postal delivery. This
strategy does not strongly protect the confidentiality of the
student's information in transit, nor does this strategy allow the
recipient to automate verification or other processing of the
received transcript information. Sending a paper transcript sealed
in a postal envelope better protects student confidentiality, but
similarly restricts the recipient's ability to verify or process
transcript contents. By copying his digital transcript onto a CD-ROM
storage disk and sending that disk, sealed in a postal envelope, via
surface mail, the recipient can automatically verify and process the
transcript content, although protection of student confidentiality in
transit might be stronger.
Alternatively, a student could send a copy of the digital transcript
provided by his secondary school merely by attaching the relevant
computer file to an email message addressed to the recipient. If the
student completely trusts the end-to-end email transmission path from
himself to his intended recipient (e.g., if student and recipient are
connected by a common, private network), then the student could send
his transcript in a plaintext email; otherwise, the student SHOULD
encrypt the email contents to protect his privacy during
transmission.
If a student chooses to convey his/her school transcript to a
transcript recipient via electronic mail, then the principal
responsibilities of that student are:
1. Create a personal email account and associated email address from
which transmissions of the student's signed school transcript may
be sent.
2. For each potential recipient of the student's signed school
transcript, discover and record the email address and the public
OpenPGP key published by that transcript recipient.
3. Import the OpenPGP public key for each chosen recipient into the
local OpenPGP key database.
4. Use an email client application that implements the OpenPGP/MIME
specification [RFC3156] in order to encrypt and transmit a copy
of the signed school transcript to each chosen recipient.
Using common formats and methods to convey transcript content
protects students while also simplifying processing for transcript
recipients. The representation of transcripts as specified in
Section 5 and the use of the transmission formats specified in
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Section 6 afford privacy and autonomy to students. By using these
formats, recipients may independently verify the origin and integrity
of the transcript information that students provide. Common
transcript representation also allows recipients to automate the
storage, analysis, and review of received transcripts.
However, a student cannot use the format specified here to convey
his/her transcript to a chosen recipient unless that recipient is
prepared to participate in the exchange. The principal
responsibilities of a transcript recipient are:
1. Generate an OpenPGP key pair that can be used to encrypt student
transmissions of signed school transcripts to the recipient.
2. Create and securely store a key revocation certificate for the
key pair generated above for possible future use in the event
that the private key component is compromised.
3. Create a (preferably dedicated) email address and mailbox to
which students may direct transmissions of signed school
transcripts.
4. Publish on the World Wide Web both the dedicated transcript email
address and the public component of the OpenPGP key pair
generated above, together with its OpenPGP fingerprint.
5. Securely store the private component of the OpenPGP key pair
generated above and guard its use with a judiciously chosen
passphrase known only to the transcript recipient.
6. Assemble a collection of public OpenPGP keys published by
legitimate transcript originators.
7. Receive and decrypt transcripts transmitted by students.
8. Validate the origin and integrity of each received transcript
using the public OpenPGP key of the relevant transcript
originator.
The similarity between the EESST transcript format and generic
OpenPGP/MIME email messages allows transcript recipients to inspect,
verify, and extract received school transcripts using existing,
widely deployed email clients. By using email client applications
that support both the MIME and OpenPGP specifications, transcript
recipients should easily be able to verify the signature of the
transcript originator and to save the various transcript components
locally for later review or processing.
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Using familiar email client applications for receiving and reviewing
small numbers of received school transcripts does not preclude using
more automated systems to meet the needs of university admissions
departments or large employers. Larger-volume transcript recipients
might ask students to direct their school transcripts to a particular
email mailbox. Transcripts so delivered could be periodically
received, validated, and otherwise organized by specialized
application software. Information in the computational component of
received transcripts might be incorporated into a candidate database
to simplify more quantitative evaluations of the applicant pool.
4. Transcript Content
The content of a school transcript is represented as a single MIME
body part whose content type is "multipart/mixed". This multipart
representation comprises individual MIME elements that represent (in
order) prefatory comments from the transcript originator regarding
the validation and interpretation of the represented transcript
(described in Section 4.1), a rendering of the relevant school
transcript suitable for automated processing (described in
Section 4.2), and a rendering of that same school transcript suitable
for human review and consideration (described in Section 4.3).
Figure 3 below schematically presents the MIME structure used to
represent transcript content; Figure 4 illustrates an example
representation of transcript content.
Every representation of transcript content MUST include exactly the
following set of MIME content headers:
Content-Type: This header is defined in Section 5 of the MIME format
specification [RFC2045] and, when associated with the content of
a signed school transcript, MUST have the value "multipart/
mixed".
Content-Description: This header is defined in Section 8 of the MIME
format specification [RFC2045]. Its value provides humans with
"descriptive information" about the content of the represented
school transcript. Notwithstanding the statement in RFC 2045
that a content description header is optional, this header MUST
be included in the MIME representation of school transcript
content.
MIME-Version: This header is defined in Section 4 of the MIME format
specification [RFC2045]. Its value identifies the version of
the MIME specification to which the associated body part
conforms. Currently, the value of this header MUST always be
"1.0". Sometimes, the EESST specification can require an
appearance of the MIME-Version header where it is not otherwise
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strictly required by the MIME format specification. These
seemingly gratuitous MIME-Version headers are deliberately
introduced to help users who may need to apply less-capable
email clients recursively in order to navigate and display a
transmitted transcript.
Eesst-Version: The value of this header identifies the version of
the EESST format to which the represented school transcript
conforms. Currently, the value of this header MUST always be
"1.0".
From: The value of this header identifies the originator of the
represented school transcript. This value names the originating
official, his organizational title, and includes, enclosed
within angle brackets, the identity of the OpenPGP key with
which the represented school transcript has been digitally
signed.
Organization: The value of this header identifies the organization
or institution to which the originator of the relevant message
belongs. Within a school transcript document, the value of this
header identifies the secondary school that has issued the
represented school transcript. By convention, the value of this
header names the originating institution along with its
geographical location.
Subject: The value of this header provides humans with "descriptive
information" about the semantic content of the represented
school transcript. Inclusion of this header is optional, but,
if included, its value MUST match that of the "Content-
Description" header above. The presence of the "Subject" header
helps some email reader applications to present school
transcript transmissions more elegantly.
Date: The value of this header identifies the date on which the
represented school transcript was created, and its format MUST
be consistent with Section 3.3 of the specification for email
messages [RFC5322].
With the exception of the optional "Subject" header, each header
enumerated above must appear in the MIME body part that represents
the aggregate content of a school transcript. No other headers are
permitted, and the allowed set of headers may appear in any order.
Example MIME headers for transcript content are presented in
Figure 4. In the figure, "PESC" stands for the Postsecondary
Electronic Standards Council; see Section 4.2 for more information.
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RFC 7681 EESST Protocol Specification October 2015
+--------------------------------------------------+
| TRANSCRIPT CONTENT |
| Content-Type: multipart/mixed |
| |
| +-------------------------------------------+ |
| | TRANSCRIPT PREFACE | |
| | Content-Type: text/plain | |
| | | |
| | Body represents transcript preface | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | COMPUTATIONAL TRANSCRIPT | |
| | Content-Type: application/xml | |
| | | |
| | Body represents PESC XML computational | |
| | transcript | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | DISPLAY TRANSCRIPT | |
| | Content-Type: application/pdf | |
| | | |
| | Body represents PDF display transcript | |
| +-------------------------------------------+ |
+--------------------------------------------------+
Figure 3: MIME Structure of Transcript Content
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RFC 7681 EESST Protocol Specification October 2015
Content-Type: multipart/mixed; boundary="===============BBBBBBBBBB=="
MIME-Version: 1.0
Content-Description: Official School Transcript for Hermione Granger
Subject: Official School Transcript for Hermione Granger
From: Transcript Authority at Hogwarts School
<transcript-authority@hogwarts.edu.example>
Organization: Hogwarts School for Witchcraft and Wizardry
Eesst-Version: 1.0
Date: Fri, 22 Mar 2013 09:55:06 -0600
--===============BBBBBBBBBB==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="preface.txt"
Content-Description: School Transcript Preface
To Whom It May Concern:
This academic transcript describes the accomplishments of an
...
--===============BBBBBBBBBB==
Content-Type: application/xml
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Content-Disposition: attachment; filename="transcript.xml"
Content-Description: School Transcript rendered as PESC XML
<HSTrn:HighSchoolTranscript=20xmlns:AcRec=3D"urn:org:pesc:sector:Acad
...
cord></Student></HSTrn:HighSchoolTranscript>
--===============BBBBBBBBBB==
Content-Type: application/pdf
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="transcript.pdf"
Content-Description: School Transcript rendered as PDF
JVBERi0xLjMNCiWTjIueIFJlcG9ydExhYiBHZW5lcmF0ZWQgUERGIGRvY3VtZW50IGh0d
...
IC9Sb290IDEwIDAgUg0KIC9TaXplIDE2ID4+DQpzdGFydHhyZWYNCjE3OTIzDQolJUVPR
--===============BBBBBBBBBB==
Figure 4: Example Transcript Content
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4.1. School Transcript Preface
A school transcript preface conveys generic comments about a school
transcript from the originating school official. This commentary is
in a form that is widely readable by humans without special
application tools. This commentary SHOULD be generic in character,
providing general information about the preparation and
interpretation of transcripts issued by the originating institution;
the transcript preface SHOULD NOT provide information about an
individual student. The rhetorical form of a transcript preface is
sometimes that of a cover letter addressed to a generic transcript
recipient. For example, a preface could provide instructions on how
to verify the digital signature on the transcript or an explanation
of unusual grading practices at the issuing school. A school
transcript preface is represented as a MIME body part whose content
type is "text/plain".
When a school transcript is encapsulated for transmission into a
larger email message, arbitrary text within a transcript preface
could be accidentally misinterpreted as structural MIME boundaries or
email headers. The likelihood of such errors is reduced when preface
content does not include lines that begin with hyphen (-) characters,
angle bracket (>) characters, or the word "From." Although, ideally,
the transcript preface should be readable by humans without special
assistance, when these constructs absolutely cannot be avoided within
preface text, transcript originators SHOULD apply a content transfer
encoding to the preface that insulates it from misinterpretation by
intermediary mail transfer agents.
The representation of a transcript preface SHOULD NOT include any
header fields beyond those enumerated in the specification for the
format of MIME message bodies [RFC2045].
4.2. Computational School Transcript
A computational school transcript represents the academic
accomplishments of an individual student in a form suitable for
automated processing. Accordingly, the content of a computational
school transcript is rendered in Extensible Markup Language (XML)
[XML11] and conveyed as a MIME body part whose content type is
"application/xml". The syntax of the data conveyed by a
computational transcript MUST conform to the XML schema for High
School Transcripts, Version 1.3.0 [Fun12b], published by the
Postsecondary Electronic Standards Council (PESC). This XML schema
depends in turn upon the Academic Record XML schema, Version 1.7.0
[Fun12a] and the Core Main XML schema, Version 1.2.0 [Mar06], also
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RFC 7681 EESST Protocol Specification October 2015
published by PESC. Detailed semantics for the data elements defined
by these XML schema are defined in the PESC XML implementation guide,
Version 1.3.0 [Ste12], which also provides usage examples.
In order to protect student privacy, this specification does not
require a school transcript to convey any particular student
information but, rather, defines only a common format for whatever
student information may be voluntarily exchanged between consenting
parties. The scope of the information exchanged is a completely
local matter, and a transcript originator MAY omit from transcript
content any information (e.g., a student's social security number,
the identity and location of a student's parents, a student's race,
ethnicity, or transgender status) that might be regarded locally as
sensitive or irrelevant. Indeed, the requirement that a
computational transcript conform syntactically to the PESC XML schema
imposes few, if any, constraints upon the transcript originator's
choices regarding transcript content. Figure 5 illustrates a minimal
set of XML elements that satisfies the syntactic requirements of the
PESC XML schema. A computational transcript need convey no more
information about an individual student than what little is conveyed
by that figure.
In order to prevent implicit monitoring and control of student
interactions with transcript recipients, this specification restricts
certain uses of the PESC XML schema by transcript originators. In
every computational transcript, the "Destination" sub-element of the
"DataTransmission" element MUST convey no distinguishable information
and have the particular representation
"<Destination><Organization/></Destination>"
that is illustrated in Figure 5. This requirement assures that a
student may use self-made copies of a signed transcript document for
whatever purposes he/she chooses without further consultation with
issuing school officials. If the transcript originator is allowed to
brand particular destinations onto each copy of a student transcript,
then the originator can easily monitor and (to some degree) control
the set of college admissions officers, prospective employers, or
other third parties to whom the student is providing that transcript.
Transcript recipients MUST reject any transcript whose content in any
way specifies or restricts the audience, recipient, or distribution
for that transcript. Notwithstanding this restriction upon the
"Destination" element, the "Source" element SHOULD be included within
a computational transcript and convey information sufficient to
identify the secondary school or other institution by which the
relevant transcript is issued.
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<HSTrn:HighSchoolTranscript
xmlns:HSTrn="urn:org:pesc:message:HighSchoolTranscript:v1.3.0"
xmlns:AcRec="urn:org:pesc:sector:AcademicRecord:v1.7.0"
xmlns:core="urn:org:pesc:core:CoreMain:v1.12.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:org:pesc:message:HighSchoolTranscript:v1.3.0
HighSchoolTranscript_v1.3.0.xsd">
<TransmissionData>
<DocumentID>X</DocumentID>
<CreatedDateTime>2011-04-04T09:30:47-05:00</CreatedDateTime>
<DocumentTypeCode>StudentRequest</DocumentTypeCode>
<TransmissionType>MutuallyDefined</TransmissionType>
<Source>
<Organization/>
</Source>
<Destination>
<Organization/>
</Destination>
</TransmissionData>
<Student>
<Person>
<Name/>
</Person>
<AcademicRecord/>
</Student>
</HSTrn:HighSchoolTranscript>
Figure 5: A Minimal Set of PESC XML Elements
Additional restrictions on the use of the PESC XML schema foster
common, unambiguous interpretation and simplified processing of
computational transcripts:
1. In order to satisfy the minimal syntactic requirements of the
PESC XML schema, every computational transcript MUST comprise at
least those XML elements that appear in Figure 5. Even when a
transcript originator seeks to convey no information within a
computational transcript, the computational transcript must be
included within the relevant transcript content, and its payload
must have the form illustrated in Figure 5.
2. Consistent with the PESC XML schema, any value ascribed to the
"DocumentID" XML element must be at least one non-whitespace
character in length.
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3. Consistent with the PESC XML schema, any value ascribed to the
"CreatedDateTime" XML element must have the form of an XML
"dateTime" value, as defined in Section 3.2.7 of the XML Schema
Datatype specification [XSD].
4. Lest the origin and correct handling for a computational
transcript be misunderstood, the value ascribed to the
"DocumentTypeCode" XML element MUST be "StudentRequest".
5. Lest the origin and correct handling for a computational
transcript be misunderstood, the value ascribed to the
"TransmissionType" XML element MUST be "MutuallyDefined".
6. With the exception of those XML elements that appear in Figure 5,
information that is not provided in a computational transcript
MUST be represented by entirely omitting the relevant XML data
element; omitted information MUST NOT be represented by including
an XML element whose textual value is of zero length or contains
only whitespace.
The representation of a computational transcript SHOULD NOT include
any header fields beyond those enumerated in the specification for
the format of MIME message bodies [RFC2045]. Although any valid
content transfer encoding is acceptable for a computational school
transcript, the "quoted-printable" encoding is preferred.
4.3. Display School Transcript
A display school transcript describes the academic accomplishments of
an individual student in a form suitable for human reading and
review. A display school transcript is represented as a MIME body
part whose content type is "application/pdf" and whose content
conforms to the Portable Document Format (PDF) specification [PDF17].
A display school transcript may comprise one or more physical pages.
In order to reduce the chance that the recipient of a signed school
transcript could misinterpret its content, the computational
component (described in Section 4.2 above) and the display component
(defined here) of each signed school transcript SHOULD convey, to the
greatest degree possible, identical information about the academic
accomplishments of the relevant student.
Nothing in this specification should be construed as requiring
implementation or use of digital signature features embedded in
individual PDF documents pursuant to the PDF specification. Rather,
the data integrity and origin identity of all components in a school
transcript --- including the PDF display transcript --- are
adequately protected by the OpenPGP signature of the transcript
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originator, required by this specification. Accordingly,
implementation of PDF-specific signature features is optional and
largely unwarranted; although transcript recipients MUST accept
transcripts that include PDF signatures, recipients SHOULD neither
verify nor depend upon the embedded signatures themselves.
Transcript originators MUST NOT use the encryption features described
in the PDF specification to encrypt a display school transcript. The
OpenPGP encryption mechanisms specified in Section 6 below adequately
protect the confidentiality of student information while in transit.
Thus, separately encrypting the display transcript is redundant.
Double encryption increases implementation complexity while also
increasing security risk by requiring additional key distributions.
Transcript recipients MUST NOT accept or process school transcripts
for which the PDF display component is independently encrypted.
Previous work [RFC3778] identifies security considerations arising
from using the PDF as a MIME media type. Among these considerations
is that PDF documents may include executable "scripts" or references
to external, executable plug-in modules. Including arbitrary
executable programs (or references thereto) in a PDF transcript
document poses a security risk to transcript recipients. Digitally
signing PDF documents (or even the transcripts that contain them)
does not help transcript recipients to evaluate the safety of
executing any embedded programs or plug-ins. The primary purpose of
using PDF is to present static transcript information in an
attractive format for human review. Because this limited purpose is
admirably served without embedding executable elements in PDF files,
any risk posed by their inclusion is unwarranted. Accordingly,
transcript originators MUST NOT include in a PDF display transcript
any executable scripts or external plug-in references. In order to
preclude execution of untrusted programs on their local system,
transcript recipients SHOULD use only trusted tools to process and
view display transcripts.
The representation of a display school transcript SHOULD NOT include
any header fields beyond those enumerated in the specification for
the format of MIME message bodies [RFC2045].
5. Signed School Transcript
A signed school transcript is a MIME body part whose form corresponds
to that of a signed OpenPGP/MIME message, as described in section 5
of the OpenPGP/MIME specification [RFC3156]. Accordingly, the MIME
content type of a signed school transcript is "multipart/signed", and
its form reflects the traditional use of multipart MIME structures to
secure email communication [RFC1847]. Thus, the body of a signed
school transcript comprises exactly two parts, as illustrated in
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Figure 6. The first part of the signed transcript body conveys the
transcript content, in MIME canonical format, including an
appropriate set of MIME content headers. The form and interpretation
of the transcript content is described in Section 4 above. The
second part of the signed transcript body is the school transcript
signature. The signature part represents the OpenPGP digital
signature of the transcript originator as it has been applied to the
transcript content conveyed by the first part of the signed
transcript. The transcript signature is assigned the content type
"application/pgp-signature". Transcript recipients MUST reject
transcripts that are not validly signed pursuant to the specification
for OpenPGP signatures [RFC3156].
+--------------------------------------------------+
| SIGNED TRANSCRIPT |
| Content-Type: multipart/signed |
| |
| +-------------------------------------------+ |
| | TRANSCRIPT CONTENT | |
| | Content-Type: multipart/mixed | |
| | | |
| | Body represents transcript content | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | TRANSCRIPT SIGNATURE | |
| | Content-Type: application/pgp-signature | |
| | | |
| | Body represents OpenPGP signature over | |
| | transcript content | |
| +-------------------------------------------+ |
+--------------------------------------------------+
Figure 6: MIME Structure of Signed Transcript
With the sole exception of the "Content-Type" header, the MIME
content headers for each signed school transcript MUST correspond
exactly to those for the embedded transcript content, as described
above in Section 4. For a signed school transcript, the value of the
"Content-Type" header MUST be "multipart/signed", its parameters MUST
conform to those described in Section 5 of the MIME/OpenPGP
specification [RFC3156], and the value of the "boundary" parameter
shall, of course, differ from all other boundary parameter values
within the same message. Figure 7 presents example headers for a
signed school transcript. Although the allowed headers may appear in
any order, transcript recipients MUST reject signed transcripts for
which the set of included headers differs from the set of headers
associated with the embedded transcript content.
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Content-Type: multipart/signed;
protocol="application/pgp-signature";
micalg="pgp-sha256";
boundary="===============AAAAAAAAAA=="
MIME-Version: 1.0
Content-Description: Official School Transcript for Hermione Granger
Subject: Official School Transcript for Hermione Granger
From: Transcript Authority at Hogwarts School
<transcript-authority@hogwarts.edu.example>
Organization: Hogwarts School for Witchcraft and Wizardry
Eesst-Version: 1.0
Date: Fri, 22 Mar 2013 09:55:06 -0600
--===============AAAAAAAAAA==
Content-Type: multipart/mixed; boundary="===============BBBBBBBBBB=="
MIME-Version: 1.0
Content-Description: Official School Transcript for Hermione Granger
... Transcript Content as illustrated in Figure 4 ...
--===============BBBBBBBBBB==--
--===============AAAAAAAAAA==
Content-Type: application/pgp-signature; name="signature.asc"
MIME-Version: 1.0
Content-Description: OpenPGP signature
Content-Disposition: attachment; filename="signature.asc"
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
iQEcBAABAgAGBQJRmkkLAAoJEBzD54azv/d4j4gH/1Aj8poEHLsEhxdv26H76URX
...
8/SQRZGUGUC0xSej5uQMVI59Yriy3dedlzib7EadK6fnz70SsEzUcQy5lHFkNNA=
=8QLW
-----END PGP SIGNATURE-----
--===============AAAAAAAAAA==--
Figure 7: Example Signed School Transcript
The "Eesst-Version" header serves a crucial if non-obvious purpose
for protocol implementors. The presence of this header unambiguously
distinguishes a signed school transcript from elements of an
enveloping email message by which that transcript may be conveyed.
For good reason, the format defined here for signed school
transcripts intentionally shares many characteristics with the
standard format for OpenPGP/MIME messages [RFC3156]. This similarity
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not only admits some code reuse within recipient implementations,
but, most importantly, also allows transcript recipients to inspect,
verify, and extract received school transcripts using existing,
widely deployed email clients.
However, the formal similarity between signed school transcripts and
generic signed messages can complicate recipient implementations of
the transcript exchange protocol, because every signed body part must
be fully evaluated to determine its status. When a signed school
transcript is conveyed to its recipient enclosed within a signed
OpenPGP email message, both transcript and conveying message share
the common MIME type "multipart/signed". Moreover, both signed
transcript and its conveying message share a common, high-level
structure comprising exactly two MIME body parts, independently
representing the signed content and the applied digital signature.
When a "multipart/signed" MIME body part is encountered as part of a
received email message, should that body part be construed as a
proper signed school transcript, a signed email message by which a
school transcript is conveyed, ill-formed school transcript, or
something else altogether? Without additional information,
unambiguously answering these questions requires that every signed
body part be fully verified, parsed, validated, and checked, because,
absent additional information, a receiving implementation cannot know
what tests need to be applied.
Thus, the "Eesst-Version" header serves at least two important
functions. Most obviously, this header identifies what version of
the EESST format has been applied in preparation of the relevant
transcript. Although, currently, the only acceptable version of the
EESST format is 1.0, to deny even the possibility of future protocol
evolution is to deny the lessons of history. Less obviously, the
"Eesst-Version" header allows simple, unambiguous detection of signed
school transcripts while still allowing transcript recipients to
validate and review school transcripts using familiar, widely
available email clients. For these reasons, the "Eesst-Version"
header MUST be included in signed school transcripts and their
content component, but, in order to most fully realize its value as
syntactic disambiguator, the "Eesst-Version" header MUST NOT appear
anywhere else.
6. Transcript Transmission
Provided that the transcript originator is prohibited from disclosing
personal information without student consent, use of the EESST
protocol empowers each student to limit sharing of his or her own
school transcript to recipients chosen by that student. The design
of the protocol not only protects the confidentiality of transcript
content in transit but also increases the cost of surveillance by the
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school or other interested parties of the student's interactions with
colleges, prospective employers, or other third parties.
A student may convey his signed school transcript to his chosen
recipient using any medium or technology that is agreeable to them
both. For example, a student may copy his signed digital transcript
onto a CD-ROM storage disk and send that physical medium to his
intended recipient via a postal mail service. However, because email
will frequently be the most convenient means for students to
distribute their transcripts, this specification defines a common
email format by which each student may privately convey his/her
signed school transcript to each recipient. A common form for
transcript transmission simplifies implementations of the transcript
exchange protocol and fosters their interoperability. A common
format allows high-volume transcript recipients to automate
decryption and validation of received transcripts as well as their
preparation for subsequent review and analysis. A common format that
derives from existing email standards allows low-volume transcript
recipients to use popular email client software to receive, decrypt,
validate, and review transcripts.
When a student conveys his transcript to a recipient via email, that
student's confidential transcript information is vulnerable to
interception and disclosure. In order to mitigate this threat, this
specification generally requires that the conveying email message be
encrypted as described in the OpenPGP standard [RFC3156]. Every
transcript recipient MUST be prepared to accept all transcript
transmissions that are encrypted as described in any of the sections
below. A student SHOULD use either the encrypted transmission format
(Section 6.1) or the encrypted and signed transmission format
(Section 6.2), if he or she independently trusts that the
transmitting computer will correctly transmit his or her transcript
according to the OpenPGP/MIME specification without disclosing its
plaintext content. Otherwise, students MAY use the encrypted file
transmission format (Section 6.3) or traditional inline transmission
format (Section 6.4) below. These latter formats simplify using a
more trusted computer to encrypt a student's transcript and later
transferring its encrypted form to a less trusted computer for
transmission to the chosen recipient.
Because transcript transmissions must be encrypted in order to assure
student privacy, every potential transcript recipient MUST generate
an OpenPGP key pair and publish its public component for use by
students in the preparation of those transmissions. The public key
for each transcript recipient should be published (together with its
OpenPGP fingerprint) on the web page for that recipient or in the
global OpenPGP key database. To protect the privacy of personal
information transmitted to each chosen recipient, a student need only
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retrieve the published key for that recipient and use it to encrypt
the transcript transmission.
With some effort, however, an attacker could, by masquerading as a
legitimate transcript recipient, perhaps trick a student into
transmitting private information to the attacker, encrypted in a key
that is known to the attacker. In order to protect student privacy
in the face of such attacks, a transcript recipient should resist
successful forgery of his/her OpenPGP identity by asking other
trustworthy individuals (e.g., respected colleagues or institutional
officers) to certify that identity. An OpenPGP identity is certified
by affixing another's digital signature to the associated OpenPGP key
(see Section 12 of the OpenPGP message format specification [RFC4880]
and Section 3 in the GNU Privacy Handbook [GPH]). Those who sign a
recipient's public key are implicitly vouching for the association
between that key and the true identity of the recipient. Consistent
with the view that the student bears primary responsibility for the
privacy of his/her transcript information, the student is ultimately
responsible for evaluating the authenticity of public keys that he/
she uses to encrypt that information while in transit. Adding
certifying signatures to a recipient's key reduces the chance that a
student could be deceived by an imposter.
In order to maximize student privacy and autonomy, the operation of
this protocol sharply separates the function of transcript creation
from the function of transcript transmission. The former function is
assigned exclusively to the issuing secondary school (the transcript
originator), while the latter function is assigned exclusively to the
individual student. Participants in the protocol must behave so as
to preserve the privacy afforded by this separation. A transcript
originator MUST NOT transmit, share, or distribute a school
transcript or any component thereof to any party other than the
individual student to whom it pertains. A transcript recipient MUST
reject any transcript that seems to have been transmitted by or on
behalf of anyone but the student. Although non-student transcript
transmission can be difficult to detect reliably, certain
transmission characteristics unambiguously suggest abuse of student
prerogatives. Accordingly, all recipient implementations MUST detect
and reject transcript transmissions with any of the following
characteristics:
o A transcript recipient MUST reject any transcript that is
delivered in the same email message or on the same physical
storage medium as any other.
o A transcript recipient MUST reject any transcript for which the
transcript originator and the sender of the transcript
transmission are identical.
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o A transcript recipient MUST reject any transcript for which the
transcript originator (who signs that transcript) and the signer
of the transcript transmission are identical.
o A transcript recipient MUST reject any transcript for which the
received transcript transmission is addressed to multiple
recipients.
6.1. Encrypted Format
In the encrypted transmission format, the signed school transcript is
conveyed to a single recipient as a MIME attachment to an OpenPGP
encrypted email message. Consistent with Section 4 of the OpenPGP/
MIME specification [RFC3156], the transmission email message must
have MIME content type "multipart/encrypted", and, as illustrated in
Figure 8, the body of the message must comprise exactly two parts.
The first body part must have MIME content type "application/
pgp-encrypted", and its content must include only the literal value
"Version: 1" on a line by itself. The second body part must have
MIME content type "application/octet-stream". Its content is the
result of applying the OpenPGP encryption algorithm to the MIME
canonical representation of the relevant signed school transcript.
+--------------------------------------------------+
| ENCRYPTED TRANSCRIPT TRANSMISSION |
| Content-Type: multipart/encrypted |
| |
| +-------------------------------------------+ |
| | GRATUITOUS TEXTUAL PREAMBLE | |
| | Content-Type: application/pgp-encrypted | |
| | | |
| | Body is literal "Version: 1" | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | ENCRYPTED SIGNED TRANSCRIPT | |
| | Content-Type: application/octet-stream | |
| | | |
| | Body represents OpenPGP encryption of | |
| | signed school transcript | |
| +-------------------------------------------+ |
+--------------------------------------------------+
Figure 8: MIME Structure of Encrypted Transcript Transmission
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RFC 7681 EESST Protocol Specification October 2015
6.2. Encrypted and Signed Format
In the encrypted and signed transmission format, the signed school
transcript is conveyed to a single recipient as an attachment to an
OpenPGP encrypted and signed email message. Consistent with
Section 6.1 of the OpenPGP/MIME specification [RFC3156], preparation
of a message in this format is a two-stage process. During this
process, the transcript transmission is, first, digitally signed by
the transmitting student and, second, encrypted to protect student
information from disclosure to anyone but the lone recipient.
+--------------------------------------------------+
| SIGNED TRANSCRIPT TRANSMISSION |
| Content-Type: multipart/signed |
| |
| +-------------------------------------------+ |
| | SIGNED TRANSMISSION CONTENT | |
| | Content-Type: multipart/signed | |
| | | |
| | Body is signed school transcript | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | TRANSMISSION SIGNATURE | |
| | Content-Type: application/pgp-signature | |
| | | |
| | Body is OpenPGP signature over signed | |
| | transmission content | |
| +-------------------------------------------+ |
+--------------------------------------------------+
Figure 9: MIME Structure of Signed Transcript Transmission
The first stage of preparing an encrypted and signed transcript
transmission is applying the student's signature to the transmission
content. As illustrated in Figure 9, the resulting MIME body part
has content type "multipart/signed" and comprises exactly two parts.
The first part is the signed transmission content and corresponds to
the signed school transcript in its entirety, whose structure is
illustrated in Figure 6. The second part is the transmission
signature. Its MIME content type is "application/pgp-signature", and
its content is the result of applying the OpenPGP signature
algorithm, using the student's private key, to the transmission
content, the canonical representation of the signed school
transcript, which is already signed by the transcript originator.
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+--------------------------------------------------+
| ENCRYPTED TRANSCRIPT TRANSMISSION |
| Content-Type: multipart/encrypted |
| |
| +-------------------------------------------+ |
| | GRATUITOUS TEXTUAL PREAMBLE | |
| | Content-Type: application/pgp-encrypted | |
| | | |
| | Body is literal "Version: 1" | |
| +-------------------------------------------+ |
| |
| +-------------------------------------------+ |
| | ENCRYPTED SIGNED TRANSCRIPT | |
| | Content-Type: application/octet-stream | |
| | | |
| | Body represents OpenPGP encryption of | |
| | signed transcript transmission | |
| +-------------------------------------------+ |
+--------------------------------------------------+
Figure 10: MIME Structure of Encrypted Transcript Transmission
The second stage of preparing an encrypted and signed transcript
transmission is wrapping the result of the first stage into an
OpenPGP encrypted message, protecting student information from
disclosure to anyone but the lone recipient. As illustrated in
Figure 10, the encrypted transcript transmission has the form
proscribed in Section 6.1 of the OpenPGP/MIME specification. The
MIME content type is "multipart/encrypted" and the result comprises
exactly two body parts. The first body part must have MIME content
type "application/pgp-encrypted", and its content must include only
the literal value "Version: 1" on a line by itself. The second body
part must have MIME content type "application/octet-stream". Its
content is the result of applying the OpenPGP encryption algorithm to
the MIME canonical representation of the relevant signed transcript
transmission, which was produced during the first stage of the two-
stage process.
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6.3. Encrypted File Format
Privacy protections afforded by the EESST protocol depend upon the
assumption that the computer used by the student to transmit his or
her school transcript reliably executes the required EESST protocol
operations without disclosing confidential information. In
particular, the transmitting computer is assumed to prevent any
access to the plaintext form of a school transcript by anyone but the
student. The hardware and software of the transmitting computer is
assumed to be free of any flaws that could weaken the encryption
applied to his or her transcript. The transmitting computer is also
assumed to send the transcript reliably and directly to each chosen
recipient without reporting to any third party either the fact of
this transmission or the identity of the recipient. Validating these
assumptions can be especially problematic when the student does not
unilaterally own and control the transmitting computer.
Sometimes the computer from which a student must transmit his or her
transcript cannot reasonably be trusted. Indeed, some email client
implementations manifestly do not permit students to compose a secure
email message without sharing private information with either their
email provider, system administrator, or other third party. Web-
based email clients are perhaps the most obvious and widespread
example of intrinsically insecure email platforms: neither
cryptographic keys nor plaintext message content can be safely stored
or processed on such systems. Another example of intrinsically
insecure platforms are computers and email servers provided for
student use by schools, to which, as a practical matter, school
administrators and technical staff enjoy unrestricted access.
A student may use the encrypted file transmission format when the
computer that he or she must use to transmit his or her transcript
cannot be trusted to perform the necessary encryption correctly or
without disclosing the plaintext transcript. This format simplifies
using a more trusted computer to encrypt a student's transcript and
later transferring its encrypted form to a less trusted computer for
transmission to the chosen recipient.
For example, the student may use an implementation of the OpenPGP
cryptographic algorithms on a trusted computer to encrypt the
plaintext version of his or her signed school transcript, received
from the transcript originator. The key used for this encryption is
the public OpenPGP key of the intended transcript recipient. The
binary file that results from this encryption is then transferred
(e.g., via a USB flash drive or networked file transfer protocol) to
a less trusted computer for email transmission to the chosen
recipient. On this less trusted computer, the student invokes an
email client application to compose and send a plaintext email
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message (for example, see Figure 11) to the recipient that is
formatted according to the MIME specification [RFC2045]. The binary
file containing the encrypted version of the student transcript is
included in the message as a MIME attachment whose content type is
"application/octet-stream".
When the email message is received by the transcript recipient, the
MIME attachment containing the encrypted school transcript may be
detached and saved as a binary file on the local disk. A local
OpenPGP implementation is invoked to decrypt the saved file using the
private OpenPGP encryption key generated by the transcript recipient.
The process of detaching and decrypting the attached school
transcript may be automated by large-volume transcript recipients.
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Message-ID: <55650A7F.7090800@granger-dentistry.com.example>
Date: Tue, 26 May 2015 20:06:23 -0400
From: Hermione Granger <hermione@granger-dentistry.com.example>
MIME-Version: 1.0
To: Dean Vernon Wormer <transcript-receiver@faber.edu.example>
Subject: Transmission of School Transcript
Content-Type: multipart/mixed;
boundary="------------010307000006020005010307"
This is a multi-part message in MIME format.
--------------010307000006020005010307
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Dear Dean Wormer:
Please find attached my high school transcript, encrypted in the
public encryption key published by Faber College for transcript
transmission. I stored the plaintext signed transcript that I
received from my high school on my own secure computer under the
filename TrnGranger.eml and encrypted its contents for transmission
by invoking the following command:
gpg --encrypt --recipient transcript-receiver@faber.edu TrnGranger.eml
The resulting encrypted file, TrnGranger.eml.gpg, is attached to
this email message. Save that file to the disk on your local
computer and decrypt the transcript by invoking the command:
gpg --output TrnGranger.eml --decrypt TrnGranger.eml.gpg
Sincerely,
Hermione Granger
--------------010307000006020005010307
Content-Type: application/octet-stream; name="TrnGranger.eml.gpg"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="TrnGranger.eml.gpg"
hQEMA4Fu2Js7ulkaAQf/aeiLeoy9L+YddGr0HieHd3KH3wiqLnaImsBaLfboGx+EdTIRn
...
cSJlVDOZKj6nPULT5zqYsfTEHPf+5escZab4J2Rkt/w1BhNDtulNJrbv6q2lk3xBzlt+Z
kQ==
--------------010307000006020005010307--
Figure 11: Encrypted File Transcript Transmission
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6.4. Traditional Inline Format
A student may use the traditional inline transmission format when the
computer that he or she must use to transmit his or her transcript
cannot be trusted to perform the necessary encryption correctly or
without disclosing the plaintext transcript. In common with the
encrypted file transmission format described above (Section 6.3), the
traditional inline format simplifies using a more trusted computer to
encrypt a student's transcript and later transferring its encrypted
form to a less trusted computer for transmission to the chosen
recipient.
The traditional inline format allows a student to use an
implementation of the OpenPGP cryptographic algorithms on a trusted
computer to encrypt the plaintext version of his or her signed school
transcript, received from the transcript originator. The key used
for this encryption is the public OpenPGP key of the intended
transcript recipient. The encrypted transcript is represented as an
ASCII-armored text file that is then transferred (e.g., via a USB
flash drive or networked file transfer protocol) to a less trusted
computer for email transmission to the chosen recipient. On this
less trusted computer, the student invokes an email client
application to compose and send a plaintext email message to the
recipient. The content of the ASCII-armored file containing the
encrypted version of the student transcript is pasted (or otherwise
inserted) into the new email message as the sole content of its body.
A traditional inline transcript transmission has the form of a simple
email message (in the Internet Message Format [RFC5322]) whose body
is exclusively and entirely the encrypted form of the signed school
transcript being transmitted. Representation of the included
transcript MUST conform to the OpenPGP Message Format specification
[RFC4880] for the ASCII-armored encoding of the OpenPGP encryption of
the canonical MIME representation of the relevant signed school
transcript. An example inline transcript transmission is illustrated
in Figure 12.
When the email message is received by the transcript recipient, a
local OpenPGP implementation is invoked to extract and decrypt the
inline representation of the encrypted school transcript, using the
private OpenPGP encryption key generated by the transcript recipient.
The process of extracting and decrypting the transmitted school
transcript may be automated by large-volume transcript recipients.
While the traditional inline format is an acceptable method of secure
transcript transmission, it is probably best suited to students who
lack ready alternatives. Because inline representation of OpenPGP
messages can sometimes be incompatible with other email features and
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conventions, the encrypted file format may be a better alternative
for transcript transmissions when the transmitting computer cannot be
trusted. A brief essay by Josefsson [Jos07] identifies multiple
difficulties that can arise from use of inline OpenPGP, although none
is strictly relevant to a correctly formed EESST transcript
transmission. Accordingly, the traditional inline format may be used
when needed but only with full consideration of its potential
limitations on interoperability.
Return-Path: <hermione@granger-dentistry.com.example>
Delivered-To: transcript-receiver@faber.edu.example
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain
Date: Wed, 3 Jul 2013 12:40:01 -0400
From: Hermione Granger <hermione@granger-dentistry.com.example>
To: Transcript Receiver at Faber College
<transcript-receiver@faber.edu.example>
Subject: Encrypted Inline Transmission of School Transcript
X-Mailer: smtp-cli 3.3, see http://smtp-cli.logix.cz
Content-Transfer-Encoding: 8bit
Message-ID: <1372869801.14441.1.camel@hermione>
-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.4.10 (GNU/Linux)
hQEMA4Fu2Js7ulkaAQf9Fm4+75kE6gQ1T8pjzf4GJhtBqxTTh2AaGtKZkZy9TW8h
zsbSNzZuTVf8QvJRSfk0mZywRG42dilf4Zoygpj3xJgKf7JlCEXnY5m4Luq5hvnW
...
hKgY5Kye/cu/4qwYdFOiljkMR1tv1Avh37OmmcMOZ6Hy9gbdrgQzHsPVWLDQNUYy
jxUAN8thZooRj/jHgq23EZaNyKxD
=Dga7
-----END PGP MESSAGE-----
Figure 12: Traditional Inline Signed Transcript Transmission
7. Security Considerations
The security of the EESST protocol depends upon the security of the
OpenPGP protocols on which it is based. Although the cryptographic
algorithms included in OpenPGP are among the strongest used in any
known protocol, the integrity, authenticity, and confidentiality of
conveyed student information is not assured unless EESST protocol
implementors and users faithfully observe all requirements and
recommendations of the relevant specifications ([RFC4880], [RFC3156],
and [RFC4270]). In particular, the SHA-256 digest algorithm and RSA
key lengths of at least 2048 bits MUST be used. Happily, these are
supported by all major OpenPGP implementations.
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7.1. Originator Private Key
The authority and integrity of generated school transcripts depend on
the continued secrecy of the private cryptographic key by which those
transcripts are signed. For greatest security, the guidance director
should be physically present when and where the computer program is
invoked to generate and sign the transcripts.
When an OpenPGP public-private key pair is generated for use by a
transcript originator, a key revocation certificate should also be
generated and securely stored. In the event that the generated key
pair is compromised, the stored revocation certificate may be used to
notify others to reject subsequent uses of that key.
7.2. Originator Public Key
The public cryptographic key for each transcript originator should be
published (together with its OpenPGP fingerprint) on the web page for
the originating institution and/or in the global OpenPGP key
database. Instructions for retrieving and validating the
originator's public key should be included in the preface of all
issued transcripts.
An association of school guidance professionals may wish to publish
an online collection of OpenPGP public keys submitted by their
members. A college admissions officer (or other high-volume
transcript recipient) could then download and import this key
collection into a local key database for use in verifying received
transcripts.
7.3. Originator Certification
In order to reduce the chance that an imposter might successfully
masquerade as a particular transcript originator and substitute a
false key for the authentic one, the identification of each
transcript originator with a particular OpenPGP key should be
certified by other well-known, trustworthy officials. To this end,
the public key for a transcript originator should be signed by other
officials of the originating secondary school, e.g., its principal,
senior faculty, or local school board members. The OpenPGP public
keys of these certifying officials should be published.
7.4. Recipient Public Key
The public cryptographic key for each transcript recipient should be
published (together with its OpenPGP fingerprint) on the web page for
the receiving institution and/or in the global OpenPGP key database.
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7.5. Secure Clients
The cryptographic operations upon which the security properties of
this protocol depend must be performed in private by the relevant
stakeholder. The confidentiality of a student's personal transcript
information cannot be sustained if others enjoy unauthorized access
to that content during the process of encryption. The integrity of
an originator's signature on each transcript cannot be assured if
others can learn the originator's secret key by observing the
signature process. The confidentiality of personal information sent
by many students to a particular transcript recipient cannot be
assured if others can learn that recipient's secret key by observing
the decryption of received transcripts. Therefore, every stakeholder
should perform the cryptographic operations proscribed here only when
present at a physically isolated computer that is entirely controlled
by that stakeholder and that locally stores all keys and confidential
information. Using "thin clients" or web-based computing to perform
sensitive cryptographic operations forfeits whatever protections this
protocol might have otherwise afforded.
7.6. Automatic Replies
Recipient implementations should not reply automatically or routinely
to received transcript transmissions. Such replies could provide
valuable feedback to an attacker, especially if they can be elicited
at will.
8. IANA Considerations
The EESST exchange format is compatible with and entails no
alterations to existing email standards. Indeed, the syntactic
similarity between the exchange format and standardized email message
formats empowers users to apply widely deployed email tools to
verify, interpret, or otherwise manipulate secondary school
transcripts.
In the hope of preventing any incompatibilities that could arise from
future standards evolution or changes in common usage, this section
describes the registration of two message header fields that are used
in the EESST exchange format but currently lack any formal definition
in existing standards. Consistent with registration procedures
defined in RFC 3864 [RFC3864], the subsections below describe
additions to the "Message Headers" registry maintained by the
Internet Assigned Numbers Authority.
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8.1. Registration of Eesst-Version Header
The "Eesst-Version" message header field is completely internal to
the EESST transcript format, and, indeed, explicitly precluded from
appearing within an enveloping email message (see Section 5).
Registration has been completed in order to discourage its use in
other contexts.
Header field name: Eesst-Version
Applicable protocol: mail
Status: provisional
Author/Change controller: James R. Davin
info@eesst.org
http://www.eesst.org
Specification document(s): RFC 7681
Related information:
The value of this header field identifies the version of the
EESST exchange format to which the represented school transcript
conforms. This header may appear only within EESST school
transcripts.
8.2. Registration of Organization Header
The EESST exchange format entails use of the "Organization" message
header field to identify the originating institution for a student
transcript. A header field of this name and semantics is already
defined for use within network news articles (see [RFC5536]).
Moreover, the "Organization" header field also frequently appears in
electronic mail messages, although, perhaps surprisingly, it
currently lacks any explicit, written definition in that context.
This registration publicly documents ongoing use of this header field
and may discourage incompatible uses in future.
Header field name: Organization
Applicable protocol: mail
Status: informational
Author/Change controller: James R. Davin
info@eesst.org
http://www.eesst.org
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RFC 7681 EESST Protocol Specification October 2015
Specification document(s): RFC 7681
Related information:
The value of this header field identifies the organization or
institution to which the originator of the relevant message
belongs.
Note: this field is quite distinct from the mail address fields
MTS.OrganizationName and MTS.OrganizationalUnitNames used in
X.400 mail.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
9.2. Informative References
[Fun12a] Funck, J., "XML Schema for the PESC Format for Academic
Record Data Elements, Version 1.7.0", June 2012,
<http://www.pesc.org/library/docs/standards/
High%20School%20Transcript/AcademicRecord_v1.7.0.xsd>.
[Fun12b] Funck, J., "XML Schema for the PESC Format for High School
Transcripts, Version 1.3.0", June 2012,
<http://www.pesc.org/library/docs/standards/
High%20School%20Transcript/
HighSchoolTranscript_v1.3.0.xsd>.
[GPH] Ashley, J., "The GNU Privacy Handbook", 1999,
<https://www.gnupg.org/gph/en/manual.pdf>.
[Jos07] Josefsson, J., "Inline OpenPGP Considered Harmful", April
2007, <http://josefsson.org/
inline-openpgp-considered-harmful.html>.
[Mar06] Marton, B., "XML Schema for the PESC Format for Core Main
Data Elements, Version 1.2.0", February 2006,
<http://www.pesc.org/library/docs/standards/
High%20School%20Transcript/CoreMain_v1.2.0.xml>.
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[PDF17] Adobe Systems, Inc., "Document Management - Portable
Document Format - Part 1: PDF 1.7, First Edition", July
2008, <http://wwwimages.adobe.com/www.adobe.com/content/
dam/Adobe/en/devnet/pdf/pdfs/PDF32000_2008.pdf>.
[RFC1847] Galvin, J., Murphy, S., Crocker, S., and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, DOI 10.17487/RFC1847,
October 1995, <http://www.rfc-editor.org/info/rfc1847>.
[RFC1958] Carpenter, B., Ed., "Architectural Principles of the
Internet", RFC 1958, DOI 10.17487/RFC1958, June 1996,
<http://www.rfc-editor.org/info/rfc1958>.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<http://www.rfc-editor.org/info/rfc2045>.
[RFC3156] Elkins, M., Del Torto, D., Levien, R., and T. Roessler,
"MIME Security with OpenPGP", RFC 3156,
DOI 10.17487/RFC3156, August 2001,
<http://www.rfc-editor.org/info/rfc3156>.
[RFC3778] Taft, E., Pravetz, J., Zilles, S., and L. Masinter, "The
application/pdf Media Type", RFC 3778,
DOI 10.17487/RFC3778, May 2004,
<http://www.rfc-editor.org/info/rfc3778>.
[RFC3864] Klyne, G., Nottingham, M., and J. Mogul, "Registration
Procedures for Message Header Fields", BCP 90, RFC 3864,
DOI 10.17487/RFC3864, September 2004,
<http://www.rfc-editor.org/info/rfc3864>.
[RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic
Hashes in Internet Protocols", RFC 4270,
DOI 10.17487/RFC4270, November 2005,
<http://www.rfc-editor.org/info/rfc4270>.
[RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R.
Thayer, "OpenPGP Message Format", RFC 4880,
DOI 10.17487/RFC4880, November 2007,
<http://www.rfc-editor.org/info/rfc4880>.
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
DOI 10.17487/RFC5321, October 2008,
<http://www.rfc-editor.org/info/rfc5321>.
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RFC 7681 EESST Protocol Specification October 2015
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<http://www.rfc-editor.org/info/rfc5322>.
[RFC5536] Murchison, K., Ed., Lindsey, C., and D. Kohn, "Netnews
Article Format", RFC 5536, DOI 10.17487/RFC5536, November
2009, <http://www.rfc-editor.org/info/rfc5536>.
[Sal84] Saltzer, J., Reed, D., and D. Clark, "End-to-End Arguments
in System Design", ACM Transactions on Computer
Systems 2(4), DOI 10.1145/357401.357402, November 1984,
<http://dx.doi.org/10.1145/357401.357402>.
[Ste12] Stewart, T., "Implementation Guide for the Postsecondary
Electronic Standards Council XML Standard Format for the
High School Transcript, Version 1.3.0", July 2012,
<http://www.pesc.org/library/docs/standards/
High%20School%20Transcript/XML%20HS%20Transcript%20Impl%20
Guide%20Version%201.3.0%202012%2007%2026.pdf>.
[XML11] Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E.,
Yergeau, F., and J. Cowan, "Extensible Markup Language
(XML) 1.1 (Second Edition)", W3C Recommendation
REC-xml11-20060816, August 2006,
<http://www.w3.org/TR/2006/REC-xml11-20060816>.
[XSD] Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
Second Edition", W3C Recommendation
REC-xmlschema-2-20041028, October 2004,
<http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.
Acknowledgments
Derek Atkins, Paul Hoffman, and Werner Koch provided independent
reviews of this memo. Fred Baker, Dave Crocker, Keith Moore, and
Chris Newman provided comments and questions about drafts of this
document.
Author's Address
James R. Davin
Email: info@EESST.org
URI: http://EESST.org/
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