Keywords: pervasive monitoring, privacy, security
Independent Submission S. Farrell
Request for Comments: 9446 Trinity College, Dublin
Category: Informational F. Badii
ISSN: 2070-1721 Digital Medusa
B. Schneier
Harvard University
S. M. Bellovin
Columbia University
July 2023
Reflections on Ten Years Past the Snowden Revelations
Abstract
This memo contains the thoughts and recountings of events that
transpired during and after the release of information about the
United States National Security Agency (NSA) by Edward Snowden in
2013. There are four perspectives: that of someone who was involved
with sifting through the information to responsibly inform the
public, that of a security area director of the IETF, that of a human
rights expert, and that of a computer science and affiliate law
professor. The purpose of this memo is to provide some historical
perspective, while at the same time offering a view as to what
security and privacy challenges the technical community should
consider. These essays do not represent a consensus view, but that
of the individual authors.
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 candidates for any level of Internet Standard;
see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9446.
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document authors. All rights reserved.
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Table of Contents
1. Introduction
2. Bruce Schneier: Snowden Ten Years Later
3. Stephen Farrell: IETF and Internet Technical Community Reaction
4. Farzaneh Badii: Did Snowden's Revelations Help with Protecting
Human Rights on the Internet?
5. Steven M. Bellovin: Governments and Cryptography: The Crypto
Wars
5.1. Historical Background
5.2. The Crypto Wars Begin
5.3. The Battle Is Joined
5.4. The Hidden Battle
5.5. Whither the IETF?
6. Security Considerations
7. IANA Considerations
8. Informative References
Acknowledgments
Authors' Addresses
1. Introduction
On June 6th, 2013, an article appeared in _The Guardian_ [Guard2013]
that was the beginning of a series of what have come to be known as
the Snowden revelations, describing certain activities of the United
States National Security Agency (NSA). These activities included,
amongst others: secret court orders; secret agreements for the
receipt of so-called "meta-information" that includes source,
destination, and timing of communications; and tapping of
communications lines. The breathtaking scope of the operations
shocked the Internet technical community and resulted in a sea change
within the IETF, IAB, and other standards organizations.
Now that some years have passed, it seems appropriate to reflect on
that period of time and to consider what effect the community's
actions had, where security has improved, how the threat surface has
evolved, what areas haven't improved, and where the community might
invest future efforts.
Bruce Schneier begins this compendium of individual essays by
bringing us back to 2013, recalling how it was for him and others to
report what was happening, and the mindset of those involved. Next,
Stephen Farrell reviews the technical community's reactions and in
particular the reactions of the IETF community, technical advances,
and where threats remain. Then Farzaneh Badii discusses the impact
of those advances -- or lack thereof -- on human rights. Finally
Steven M. Bellovin puts the Snowden revelations into an ever-
evolving historical context of secrets and secret stealing that spans
centuries, closing with some suggestions for IETF.
Readers are invited to consider what impact we as a community have
had, what challenges remain, and what positive contribution the
technical community can and should make to address security and
privacy of citizens of the world.
-- Eliot Lear, Independent Submissions Editor for the RFC Series
2. Bruce Schneier: Snowden Ten Years Later
In 2013 and 2014, I wrote extensively about new revelations regarding
NSA surveillance based on the documents provided by Edward Snowden.
But I had a more personal involvement as well.
I wrote the essay below in September 2013. _The New Yorker_ agreed to
publish it, but _The Guardian_ asked me not to. It was scared of UK
law enforcement and worried that this essay would reflect badly on
it. And given that the UK police would raid its offices in July
2014, it had legitimate cause to be worried.
Now, ten years later, I offer this as a time capsule of what those
early months of Snowden were like.
| It's a surreal experience, paging through hundreds of top-secret
| NSA documents. You're peering into a forbidden world: strange,
| confusing, and fascinating all at the same time.
|
| I had flown down to Rio de Janeiro in late August at the request
| of Glenn Greenwald. He had been working on the Edward Snowden
| archive for a couple of months, and had a pile of more technical
| documents that he wanted help interpreting. According to
| Greenwald, Snowden also thought that bringing me down was a good
| idea.
|
| It made sense. I didn't know either of them, but I have been
| writing about cryptography, security, and privacy for decades. I
| could decipher some of the technical language that Greenwald had
| difficulty with, and understand the context and importance of
| various document. And I have long been publicly critical of the
| NSA's eavesdropping capabilities. My knowledge and expertise
| could help figure out which stories needed to be reported.
|
| I thought about it a lot before agreeing. This was before David
| Miranda, Greenwald's partner, was detained at Heathrow airport by
| the UK authorities; but even without that, I knew there was a
| risk. I fly a lot -- a quarter of a million miles per year -- and
| being put on a TSA list, or being detained at the US border and
| having my electronics confiscated, would be a major problem. So
| would the FBI breaking into my home and seizing my personal
| electronics. But in the end, that made me more determined to do
| it.
|
| I did spend some time on the phone with the attorneys recommended
| to me by the ACLU and the EFF. And I talked about it with my
| partner, especially when Miranda was detained three days before my
| departure. Both Greenwald and his employer, _The Guardian_, are
| careful about whom they show the documents to. They publish only
| those portions essential to getting the story out. It was
| important to them that I be a co-author, not a source. I didn't
| follow the legal reasoning, but the point is that _The Guardian_
| doesn't want to leak the documents to random people. It will,
| however, write stories in the public interest, and I would be
| allowed to review the documents as part of that process. So after
| a Skype conversation with someone at _The Guardian_, I signed a
| letter of engagement.
|
| And then I flew to Brazil.
|
| I saw only a tiny slice of the documents, and most of what I saw
| was surprisingly banal. The concerns of the top-secret world are
| largely tactical: system upgrades, operational problems owing to
| weather, delays because of work backlogs, and so on. I paged
| through weekly reports, presentation slides from status meetings,
| and general briefings to educate visitors. Management is
| management, even inside the NSA. Reading the documents, I felt as
| though I were sitting through some of those endless meetings.
|
| The meeting presenters try to spice things up. Presentations
| regularly include intelligence success stories. There were
| details -- what had been found, and how, and where it helped --
| and sometimes there were attaboys from "customers" who used the
| intelligence. I'm sure these are intended to remind NSA employees
| that they're doing good. It definitely had an effect on me.
| Those were all things I want the NSA to be doing.
|
| There were so many code names. Everything has one: every program,
| every piece of equipment, every piece of software. Sometimes code
| names had their own code names. The biggest secrets seem to be
| the underlying real-world information: which particular company
| MONEYROCKET is; what software vulnerability EGOTISTICALGIRAFFE --
| really, I am not making that one up -- is; how TURBINE works.
| Those secrets collectively have a code name -- ECI, for
| exceptionally compartmented information -- and almost never appear
| in the documents. Chatting with Snowden on an encrypted IM
| connection, I joked that the NSA cafeteria menu probably has code
| names for menu items. His response: "Trust me when I say you have
| no idea."
|
| Those code names all come with logos, most of them amateurish and
| a lot of them dumb. Note to the NSA: take some of that more than
| ten-billion-dollar annual budget and hire yourself a design firm.
| Really; it'll pay off in morale.
|
| Once in a while, though, I would see something that made me stop,
| stand up, and pace around in circles. It wasn't that what I read
| was particularly exciting, or important. It was just that it was
| startling. It changed -- ever so slightly -- how I thought about
| the world.
|
| Greenwald said that that reaction was normal when people started
| reading through the documents.
|
| Intelligence professionals talk about how disorienting it is
| living on the inside. You read so much classified information
| about the world's geopolitical events that you start seeing the
| world differently. You become convinced that only the insiders
| know what's really going on, because the news media is so often
| wrong. Your family is ignorant. Your friends are ignorant. The
| world is ignorant. The only thing keeping you from ignorance is
| that constant stream of classified knowledge. It's hard not to
| feel superior, not to say things like "If you only knew what we
| know" all the time. I can understand how General Keith Alexander,
| the director of the NSA, comes across as so supercilious; I only
| saw a minute fraction of that secret world, and I started feeling
| it.
|
| It turned out to be a terrible week to visit Greenwald, as he was
| still dealing with the fallout from Miranda's detention. Two
| other journalists, one from _The Nation_ and the other from _The
| Hindu_, were also in town working with him. A lot of my week
| involved Greenwald rushing into my hotel room, giving me a thumb
| drive of new stuff to look through, and rushing out again.
|
| A technician from _The Guardian_ got a search capability working
| while I was there, and I spent some time with it. Question: when
| you're given the capability to search through a database of NSA
| secrets, what's the first thing you look for? Answer: your name.
|
| It wasn't there. Neither were any of the algorithm names I knew,
| not even algorithms I knew that the US government used.
|
| I tried to talk to Greenwald about his own operational security.
| It had been incredibly stupid for Miranda to be traveling with NSA
| documents on the thumb drive. Transferring files electronically
| is what encryption is for. I told Greenwald that he and Laura
| Poitras should be sending large encrypted files of dummy documents
| back and forth every day.
|
| Once, at Greenwald's home, I walked into the backyard and looked
| for TEMPEST receivers hiding in the trees. I didn't find any, but
| that doesn't mean they weren't there. Greenwald has a lot of
| dogs, but I don't think that would hinder professionals. I'm sure
| that a bunch of major governments have a complete copy of
| everything Greenwald has. Maybe the black bag teams bumped into
| each other in those early weeks.
|
| I started doubting my own security procedures. Reading about the
| NSA's hacking abilities will do that to you. Can it break the
| encryption on my hard drive? Probably not. Has the company that
| makes my encryption software deliberately weakened the
| implementation for it? Probably. Are NSA agents listening in on
| my calls back to the US? Very probably. Could agents take
| control of my computer over the Internet if they wanted to?
| Definitely. In the end, I decided to do my best and stop worrying
| about it. It was the agency's documents, after all. And what I
| was working on would become public in a few weeks.
|
| I wasn't sleeping well, either. A lot of it was the sheer
| magnitude of what I saw. It's not that any of it was a real
| surprise. Those of us in the information security community had
| long assumed that the NSA was doing things like this. But we
| never really sat down and figured out the details, and to have the
| details confirmed made a big difference. Maybe I can make it
| clearer with an analogy. Everyone knows that death is inevitable;
| there's absolutely no surprise about that. Yet it arrives as a
| surprise, because we spend most of our lives refusing to think
| about it. The NSA documents were a bit like that. Knowing that
| it is surely true that the NSA is eavesdropping on the world, and
| doing it in such a methodical and robust manner, is very different
| from coming face-to-face with the reality that it is and the
| details of how it is doing it.
|
| I also found it incredibly difficult to keep the secrets. _The
| Guardian_'s process is slow and methodical. I move much faster.
| I drafted stories based on what I found. Then I wrote essays
| about those stories, and essays about the essays. Writing was
| therapy; I would wake up in the wee hours of the morning, and
| write an essay. But that put me at least three levels beyond what
| was published.
|
| Now that my involvement is out, and my first essays are out, I
| feel a lot better. I'm sure it will get worse again when I find
| another monumental revelation; there are still more documents to
| go through.
|
| I've heard it said that Snowden wants to damage America. I can
| say with certainty that he does not. So far, everyone involved in
| this incident has been incredibly careful about what is released
| to the public. There are many documents that could be immensely
| harmful to the US, and no one has any intention of releasing them.
| The documents the reporters release are carefully redacted.
| Greenwald and I repeatedly debated with _The Guardian_ editors the
| newsworthiness of story ideas, stressing that we would not expose
| government secrets simply because they're interesting.
|
| The NSA got incredibly lucky; this could have ended with a massive
| public dump like Chelsea Manning's State Department cables. I
| suppose it still could. Despite that, I can imagine how this
| feels to the NSA. It's used to keeping this stuff behind multiple
| levels of security: gates with alarms, armed guards, safe doors,
| and military-grade cryptography. It's not supposed to be on a
| bunch of thumb drives in Brazil, Germany, the UK, the US, and who
| knows where else, protected largely by some random people's
| opinions about what should or should not remain secret. This is
| easily the greatest intelligence failure in the history of ever.
| It's amazing that one person could have had so much access with so
| little accountability, and could sneak all of this data out
| without raising any alarms. The odds are close to zero that
| Snowden is the first person to do this; he's just the first person
| to make public that he did. It's a testament to General
| Alexander's power that he hasn't been forced to resign.
|
| It's not that we weren't being careful about security, it's that
| our standards of care are so different. From the NSA's point of
| view, we're all major security risks, myself included. I was
| taking notes about classified material, crumpling them up, and
| throwing them into the wastebasket. I was printing documents
| marked "TOP SECRET/COMINT/NOFORN" in a hotel lobby. And once, I
| took the wrong thumb drive with me to dinner, accidentally leaving
| the unencrypted one filled with top-secret documents in my hotel
| room. It was an honest mistake; they were both blue.
|
| If I were an NSA employee, the policy would be to fire me for that
| alone.
|
| Many have written about how being under constant surveillance
| changes a person. When you know you're being watched, you censor
| yourself. You become less open, less spontaneous. You look at
| what you write on your computer and dwell on what you've said on
| the telephone, wonder how it would sound taken out of context,
| from the perspective of a hypothetical observer. You're more
| likely to conform. You suppress your individuality. Even though
| I have worked in privacy for decades, and already knew a lot about
| the NSA and what it does, the change was palpable. That feeling
| hasn't faded. I am now more careful about what I say and write.
| I am less trusting of communications technology. I am less
| trusting of the computer industry.
|
| After much discussion, Greenwald and I agreed to write three
| stories together to start. All of those are still in progress.
| In addition, I wrote two commentaries on the Snowden documents
| that were recently made public. There's a lot more to come; even
| Greenwald hasn't looked through everything.
|
| Since my trip to Brazil (one month before), I've flown back to the
| US once and domestically seven times -- all without incident. I'm
| not on any list yet. At least, none that I know about.
As it happened, I didn't write much more with Greenwald or _The
Guardian_. Those two had a falling out, and by the time everything
settled and both began writing about the documents independently --
Greenwald at the newly formed website _The Intercept_ -- I got cut
out of the process somehow. I remember hearing that Greenwald was
annoyed with me, but I never learned the reason. We haven't spoken
since.
Still, I was happy with the one story I was part of: how the NSA
hacks Tor. I consider it a personal success that I pushed _The
Guardian_ to publish NSA documents detailing QUANTUM. I don't think
that would have gotten out any other way. And I still use those
pages today when I teach cybersecurity to policymakers at the Harvard
Kennedy School.
Other people wrote about the Snowden files, and wrote a lot. It was
a slow trickle at first, and then a more consistent flow. Between
Greenwald, Bart Gellman, and _The Guardian_ reporters, there ended up
being steady stream of news. (Bart brought in Ashkan Soltani to help
him with the technical aspects, which was a great move on his part,
even if it cost Ashkan a government job later.) More stories were
covered by other publications.
It started getting weird. Both Greenwald and Gellman held documents
back so they could publish them in their books. Jake Appelbaum, who
had not yet been accused of sexual assault by multiple women, was
working with Poitras. He partnered with _Der Spiegel_ to release an
implant catalog from the NSA's Tailored Access Operations group. To
this day, I am convinced that the document was not in the Snowden
archives: that Jake got it somehow, and it was released with the
implication that it was from Edward Snowden. I thought it was
important enough that I started writing about each item in that
document in my blog: "NSA Exploit of the Week." That got my website
blocked by the DoD: I keep a framed print of the censor's message on
my wall.
Perhaps the most surreal document disclosures were when artists
started writing fiction based on the documents. This was in 2016,
when Laura Poitras built a secure room in New York to house the
documents. By then, the documents were years out of date. And now
they're over a decade out of date. (They were leaked in 2013, but
most of them were from 2012 or before.)
I ended up being something of a public ambassador for the documents.
When I got back from Rio, I gave talks at a private conference in
Woods Hole, the Berkman Center at Harvard, something called the
Congress on Privacy and Surveillance in Geneva, events at both CATO
and New America in DC, an event at the University of Pennsylvania, an
event at EPIC, a "Stop Watching Us" rally in DC, the RISCS conference
in London, the ISF in Paris, and...then...at the IETF meeting in
Vancouver in November 2013. (I remember little of this; I am
reconstructing it all from my calendar.)
What struck me at the IETF was the indignation in the room, and the
calls to action. And there was action, across many fronts. We
technologists did a lot to help secure the Internet, for example.
The government didn't do its part, though. Despite the public
outcry, investigations by Congress, pronouncements by President
Obama, and federal court rulings, I don't think much has changed.
The NSA canceled a program here and a program there, and it is now
more public about defense. But I don't think it is any less
aggressive about either bulk or targeted surveillance. Certainly its
government authorities haven't been restricted in any way. And
surveillance capitalism is still the business model of the Internet.
And Edward Snowden? We were in contact for a while on Signal. I
visited him once in Moscow, in 2016. And I had him do a guest
lecture to my class at Harvard for a few years, remotely by Jitsi.
Afterwards, I would hold a session where I promised to answer every
question he would evade or not answer, explain every response he did
give, and be candid in a way that someone with an outstanding arrest
warrant simply cannot. Sometimes I thought I could channel Snowden
better than he could.
But now it's been a decade. Everything he knows is old and out of
date. Everything we know is old and out of date. The NSA suffered
an even worse leak of its secrets by the Russians, under the guise of
the Shadow Brokers, in 2016 and 2017. The NSA has rebuilt. It again
has capabilities we can only surmise.
3. Stephen Farrell: IETF and Internet Technical Community Reaction
In 2013, the IETF and, more broadly, the Internet technical,
security, and privacy research communities, were surprised by the
surveillance and attack efforts exposed by the Snowden revelations
[Timeline]. While the potential for such was known, it was the scale
and pervasiveness of the activities disclosed that was alarming and,
I think it fair to say, quite annoying, for very many Internet
engineers.
As for the IETF's reaction, informal meetings during the July 2013
IETF meeting in Berlin indicated that IETF participants considered
that these revelations showed that we needed to do more to improve
the security and privacy properties of IETF protocols, and to help
ensure deployments made better use of the security and privacy
mechanisms that already existed. In August, the IETF set up a new
mailing list [Perpass], which became a useful venue for triaging
proposals for work on these topics. At the November 2013 IETF
meeting, there was a lively and very well attended plenary session
[Plenary-video] on "hardening the Internet" against such attacks,
followed by a "birds of a feather" session [Perpass-BoF] devoted to
more detailed discussion of possible actions in terms of new working
groups, protocols, and Best Current Practice (BCP) documents that
could help improve matters. This was followed in February/March 2014
by a joint IAB/W3C workshop on "strengthening the Internet against
pervasive monitoring" [STRINT] held in London and attended by 150
engineers (still the only IAB workshop in my experience where we
needed a waiting list for people after capacity for the venue was
reached!). The STRINT workshop report was eventually published as
[RFC7687] in 2015, but in the meantime, work proceeded on a BCP
document codifying that the IETF community considered that "pervasive
monitoring is an attack" [RFC7258] (aka BCP 188). The IETF Last Call
discussion for that short document included more than 1000 emails --
while there was broad agreement on the overall message, a number of
IETF participants considered enshrining that message in the RFC
Series and IETF processes controversial. In any case, the BCP was
published in May 2014. The key statement on which rough consensus
was reached is in the abstract of RFC 7258 and says "Pervasive
monitoring is a technical attack that should be mitigated in the
design of IETF protocols, where possible." That document has since
been referenced [Refs-to-7258] by many IETF working groups and RFCs
as justifying additional work on security and privacy. Throughout
that period and beyond, the repercussions of the Snowden revelations
remained a major and ongoing agenda item for both of the IETF's main
technical management bodies, the IAB and the IESG (on which I served
at the time).
So far, I've only described the processes with which the IETF dealt
with the attacks, but there was, of course, also much technical work
started by IETF participants that was at least partly motivated by
the Snowden revelations.
In November 2013, a working group was established to document better
practices for using TLS in applications [UTA] so that deployments
would be less at risk in the face of some of the attacks related to
stripping TLS or having applications misuse TLS APIs or parameters.
Similar work was done later to update recommendations for use of
cryptography in other protocols in the CURDLE Working Group [CURDLE].
The CURDLE Working Group was, to an extent, created to enable use of
a set of new elliptic curves that had been documented by the IRTF
Crypto Forum Research Group [CFRG]. That work in turn had been
partly motivated by (perhaps ultimately unfounded) concerns about
elliptic curves defined in NIST standards, following the DUAL_EC_DRBG
debacle [Dual-EC] (described further below) where a NIST random
number generator had been deliberately engineered to produce output
that could be vulnerable to NSA attack.
Work to develop a new version of TLS was started in 2014, mainly due
to concerns that TLS 1.2 and earlier version implementations had been
shown to be vulnerable to a range of attacks over the years. The
work to develop TLS 1.3 [RFC8446] also aimed to encrypt more of the
handshake so as to expose less information to network observers -- a
fairly direct result of the Snowden revelations. Work to further
improve TLS in this respect continues today using the so-called
Encrypted Client Hello (ECH) mechanism [TLS-ECH] to remove one of the
last privacy leaks present in current TLS.
Work on ECH was enabled by significant developments to encrypt DNS
traffic, using DNS over TLS (DoT) [RFC7858] or DNS Queries over HTTPS
(DoH) [RFC8484], which also started as a result of the Snowden
revelations. Prior to that, privacy hadn't really been considered
when it came to DNS data or (more importantly) the act of accessing
DNS data. The trend towards encrypting DNS traffic represents a
significant change for the Internet, both in terms of reducing
cleartext, but also in terms of moving points-of-control. The latter
aspect was, and remains, controversial, but the IETF did its job of
defining new protocols that can enable better DNS privacy. Work on
HTTP version 2 [RFC9113] and QUIC [RFC9000] further demonstrates the
trend in the IETF towards always encrypting protocols as the new
norm, at least at and above the transport layer.
Of course, not all such initiatives bore fruit; for example, attempts
to define a new MPLS encryption mechanism
[MPLS-OPPORTUNISTIC-ENCRYPT] foundered due to a lack of interest and
the existence of the already deployed IEEE Media Access Control
Security (MACsec) scheme. But there has been a fairly clear trend
towards trying to remove cleartext from the Internet as a precursor
to provide improved privacy when considering network observers as
attackers.
The IETF, of course, forms only one part of the broader Internet
technical community, and there were many non-IETF activities
triggered by the Snowden revelations, a number of which also
eventually resulted in new IETF work to standardise better security
and privacy mechanisms developed elsewhere.
In 2013, the web was largely unencrypted despite HTTPS being
relatively usable, and that was partly due to problems using the Web
PKI at scale. The Let's Encrypt initiative [LE] issued its first
certificates in 2015 as part of its aim to try to move the web
towards being fully encrypted, and it has been extremely successful
in helping achieve that goal. Subsequently, the automation protocols
developed for Let's Encrypt were standardised in the IETF's ACME
Working Group [ACME].
In 2013, most email transport between mail servers was cleartext,
directly enabling some of the attacks documented in the Snowden
documents. Significant effort by major mail services and MTA
software developers since then have resulted in more than 90% of
email being encrypted between mail servers, and various IETF
protocols have been defined in order to improve that situation, e.g.,
SMTP MTA Strict Transport Security (MTA-STS) [RFC8461].
Lastly, MAC addresses have historically been long-term fixed values
visible to local networks (and beyond), which enabled some tracking
attacks that were documented in the Snowden documents [Toronto].
Implementers, vendors, and the IEEE 802 standards group recognised
this weakness and started work on MAC address randomisation that in
turn led to the IETF's MADINAS Working Group [MADINAS], which aims to
ensure randomised MAC addresses can be used on the Internet without
causing unintentional harm. There is also a history of IETF work on
deprecating MAC-address-based IPv6 interface identifiers and
advocating pseudorandom identifiers and temporary addresses, some of
which pre-dates Snowden [RFC7217] [RFC8064] [RFC8981].
In summary, the significantly large volume of technical work pursued
in the IETF and elsewhere as a result of the Snowden revelations has
focussed on two main things: decreasing the amount of plaintext that
remains visible to network observers and secondly reducing the number
of long-term identifiers that enable unexpected identification or re-
identification of devices or users. This work is not by any means
complete, nor is deployment universal, but significant progress has
been made, and the work continues even if the level of annoyance at
the attack has faded somewhat over time.
One should also note that there has been pushback against these
improvements in security and privacy and the changes they cause for
deployments. That has come from more or less two camps: those on
whom these improvements force change tend to react badly, but later
figure out how to adjust, and those who seemingly prefer not to
strengthen security so as to, for example, continue to achieve what
they call "visibility" even in the face of the many engineers who
correctly argue that such an anti-encryption approach inevitably
leads to worse security overall. The recurring nature of this kind
of pushback is nicely illustrated by [RFC1984]. That informational
document was published in 1996 as an IETF response to an early
iteration of the perennial "encryption is bad" argument. In 2015,
the unmodified 1996 text was upgraded to a BCP (BCP 200) as the
underlying arguments have not changed, and will not change.
Looking back on all the above from a 2023 vantage point, I think
that, as a community of Internet engineers, we got a lot right, but
that today there's way more that needs to be done to better protect
the security and privacy of people who use the Internet. In
particular, we (the technical community) haven't done nearly as good
a job at countering surveillance capitalism [Zubhoff2019], which has
exploded in the last decade. In part, that's because many of the
problems are outside of the scope of bodies such as the IETF. For
example, intrusive backend sharing of people's data for advertising
purposes can't really be mitigated via Internet protocols.
However, I also think that the real annoyance felt with respect to
the Snowden revelations is (in general) not felt nearly as much when
it comes to the legal but hugely privacy-invasive activities of major
employers of Internet engineers.
It's noteworthy that RFC 7258 doesn't consider that bad actors are
limited to governments, and personally, I think many advertising
industry schemes for collecting data are egregious examples of
pervasive monitoring and hence ought also be considered an attack on
the Internet that ought be mitigated where possible. However, the
Internet technical community clearly hasn't acted in that way over
the last decade.
Perhaps that indicates that Internet engineers and the bodies in
which they congregate need to place much more emphasis on standards
for ethical behaviour than has been the case for the first half-
century of the Internet. And while it would be good to see the
current leaders of Internet bodies work to make progress in that
regard, at the time of writing, it sadly seems more likely that
government regulators will be the ones to try force better behaviour.
That of course comes with a significant risk of having regulations
that stymie the kind of permissionless innovation that characterised
many earlier Internet successes.
So while we got a lot right in our reaction to Snowden's revelations,
currently, we have a "worse" Internet. Nonetheless, I do still hope
to see a sea change there, as the importance of real Internet
security and privacy for people becomes utterly obvious to all, even
the most hard-core capitalists and government signals intelligence
agencies. That may seem naive, but I remain optimistic that, as a
fact-based community, we (and eventually our employers) will
recognise that the lesser risk is to honestly aim to provide the best
security and privacy practically possible.
4. Farzaneh Badii: Did Snowden's Revelations Help with Protecting Human
Rights on the Internet?
It is very difficult to empirically measure the effect of Snowden's
revelations on human rights and the Internet. Anecdotally, we have
been witnessing dominant regulatory and policy approaches that impact
technologies and services that are at the core of protecting human
rights on the Internet. (A range of European Union laws aims to
address online safety or concentration of data. There are many more
regulations that have an impact on the Internet [Masnick2023].)
There has been little progress in fixing technical and policy issues
that help enable human rights. The Snowden revelations did not
revolutionize the Internet governance and technical approaches to
support human rights such as freedom of expression, freedom of
association and assembly, and privacy. It did not decrease the
number of Internet shutdowns nor the eagerness of authoritarian (and
even to some extent democratic) countries to territorialize the
Internet. In some cases, the governments argued that they should
have more data sovereignty or Internet sovereignty. Perhaps the
revelations helped with the evolution of some technical and policy
aspects.
After Snowden's revelations 10 years ago, engineers and advocates at
the IETF responded in a few ways. One prominent response was the
issuance of a BCP document, "Pervasive Monitoring Is an Attack"
[RFC7258] by Farrell and Tschofenig. The responses to the Snowden
revelations did not mean that IETF had lost sight of issues such as
privacy and surveillance. There were instances of resistance to
surveillance in the past by engineers (we do not delve into how
successful that was in protecting human rights). However,
historically, many engineers believed that widespread and habitual
surveillance was too expensive to be practical. The revelations
proved them wrong.
Rights-centered activists were also involved with the IETF before the
revelations. For example, staff from Center for Democracy and
Technology (CDT) was undertaking work at the IETF (and was a member
of the Internet Architecture Board) and held workshops about the
challenges of creating privacy-protective protocols and systems. The
technical shortcomings that were exploited by the National Security
Agency to carry out mass-scale surveillance were recognized by the
IETF before the Snowden revelations [Garfinkel1995] [RFC6462]. In
2012, Joy Liddicoat and Avri Doria wrote a report for the Internet
Society that extensively discussed the processes and principles of
human rights and Internet protocols [Doria2012].
Perhaps the Snowden revelations brought more attention to the IETF
and its work as it related to important issues, such as privacy and
freedom of expression. It might have also expedited and helped with
more easily convening the Human Rights Protocol Considerations
Research Group (HRPC) in the Internet Research Task Force (IRTF) in
July 2015. The HRPC RG was originally co-chaired by Niels ten Oever
(who worked at Article 19 at the time) and Internet governance
activist Avri Doria. The charter of the HRPC RG states that the
group was established: "to research whether standards and protocols
can enable, strengthen or threaten human rights, as defined in the
Universal Declaration of Human Rights (UDHR) and the International
Covenant on Civil and Political Rights (ICCPR)."
During the past decade, a few successful strides were made to create
protocols that, when and if implemented, aim at protecting privacy of
the users, as well as help with reducing pervasive surveillance.
These efforts were in keeping with the consensus of the IETF found in
RFC 7258. Sometimes these protocols have anti-censorship qualities
as well. A few examples immediately come to mind: 1) the encryption
of DNS queries (for example, DNS over HTTPS), 2) ACME protocol
underpinning the Let's Encrypt initiative, and 3) Registration Data
Access Protocol (RDAP) [RFC7480] [RFC7481] [RFC8056] [RFC9082]
[RFC9083] [RFC9224]. (It is debatable that RDAP had anything to do
with the Snowden revelations, but it is still a good example and is
finally being implemented.)
The DNS Queries over HTTPS protocol aimed to encrypt DNS queries.
Four years after RFC 7258, DoH was developed to tackle both active
and passive monitoring of DNS queries. It is also a tool that can
help with combatting censorship. Before the revelations, DNS query
privacy would have been controversial due to being expensive or
unnecessary, but the Snowden revelations made it more plausible.
Let's Encrypt was not an Internet protocol, but it was an initiative
that aimed to encrypt the web, and later on some of the automation
protocols were standardized in the IETF ACME Working Group. RDAP
could solve a long-term problem: redacting the domain name
registrants' (and IP address holders') sensitive, personal data but
at the same time enabling legitimate access to the information. As
to the work of HRPC Research Group, it has so far issued [RFC8280] by
ten Oever and Cath and a number of informational Internet-Drafts.
While we cannot really argue that all the movements and privacy-
preserving protocols and initiatives that enable protecting human
rights at the infrastructure layer solely or directly result from the
Snowden revelations, I think it is safe to say that the revelations
helped with expediting the resolution of some of the "technical"
hesitations that had an effect on fixing Internet protocols that
enabled protection of human rights.
Unfortunately, the Snowden revelations have not yet helped us
meaningfully with adopting a human rights approach. We can't agree
on prioritizing human rights in our Internet communities for a host
of reasons. This could be due to: 1) human rights are sometimes in
conflict with each other; 2) it is simply not possible to mitigate
the human right violation through the Internet protocol; 3) it is not
obvious for the engineers in advance how the Internet protocol
contributes to enabling human rights protections, or precisely what
they ought to do; 4) the protocol is already there, but market, law,
and a host of other societal and political issues do not allow for
widespread implementation.
IETF did not purposefully take a long time to adopt and implement
protocols that enabled human rights. There were technical and
political issues that created barriers. For example, as WHOIS was
not capable of accommodating a tiered-access option, the IETF
community attempted a few times before to create a protocol that
would disclose the necessary information of IP holders and domain
name registrants while at the same time protecting their data (Cross
Registry Internet Service Protocol (CRISP) and later on Internet
Registry Information Service (IRIS) are the examples). However, IRIS
was technically very difficult to implement. It was not until RDAP
was developed and the General Data Protection Regulation (GDPR) was
enacted that Internet Corporation for Assigned Names and Numbers had
to consider instructing registries and registrars to implement RDAP
and its community had to come up with a privacy-compliant policy.
Overall, a host of regulatory and market incentives can halt or slow
down the implementation of human-rights-enabling protocols and
implementation could depend on other organizations with their own
political and stakeholder conflicts. Sometimes the protocol is
available, but the regulatory framework and the market do not allow
for implementation. Sometimes the surrounding context includes
practical dimensions that are easy to overlook in a purely
engineering-focused argument.
A curious example of this is sanctions regimes that target
transactions involving economically valuable assets. As a result,
sanctions might limit sanctioned nations' and entities' access to
IPv4 resources (because the existence of a resale market for these
addresses causes acquiring them to be interpreted as buying something
of value), though the same consideration may not apply to IPv6
address resources. But IPv6 adoption itself depends on a host of
complex factors that are by no means limited to technical comparisons
of the properties of IPv4 and IPv6. Someone focused only on
technical features of protocols may devise an elegant solution but be
surprised both by deployment challenges and unintended downstream
effects. Sometimes there are arguments over implementation of a
protocol because as it is perceived, while it can protect freedom of
expression and reduce surveillance, it can hamper other human rights.
For instance, the technical community and some network operators
still have doubts about the implementation of DNS over HTTPS, despite
its potential to circumvent censorship and its ability to encrypt DNS
queries. The arguments against implementation of DoH include
protection of children online and lack of law enforcement access to
data.
We must acknowledge that sometimes the technical solutions that we
use that protect one right (for example, encryption to protect the
right to privacy or to prevent surveillance) could potentially affect
technical and policy solutions that try to protect other human rights
(for example, encryption could prevent financial institutions from
monitoring employees' network activities to detect fraudulent
behavior). Acknowledging and identifying these conflicts can help us
come up with alternative techniques that could protect human rights
while not hampering other technical solutions such as encryption.
Where such alternative techniques are not possible, acknowledging the
shortcoming could clarify and bring to light the trade-offs that we
have accepted in our Internet system.
Ironically, we advocate for connectivity and believe expressing
oneself on the Internet is a human right, but when a war erupts, we
resort to tools that impact that very concept. For example, some
believe that, by imposing sanctions on critical properties of the
Internet, we can punish the perpetrators of a war. The Regional
Internet Registries that are in charge of registration of IP
addresses have shown resilience to these requests. However, some
tech companies (for example, Cogent [Roth2022]) decided not to serve
sanctioned countries and overcomplied with sanctions. Overcompliance
with sanctions could hamper ordinary people's access to the Internet
[Badii2023].
Perhaps we can solve some of these problems by undertaking a thorough
impact assessment and contextualization to reveal how and why
Internet protocols affect human rights (something Fidler and I argued
for [Badii2021]). Contextualization and impact assessment can reveal
how each Internet protocol or each line of code, in which systems,
have an impact on which and whose human rights.
The HRPC RG (which I am a part of) and the larger human rights and
policy analyst communities are still struggling to analyze legal,
social, and market factors alongside the protocols to have a good
understanding of what has an impact and what has to be changed. It
is hard, but it is not impossible. If we thoroughly document and
research the lifecycle of an Internet protocol and contextualize it,
we might have a better understanding of which parts of the protocol
to fix and how to fix them in order to protect human rights.
Overall, the revelations did, to some extent, contribute to the
evolution of our ideas and perspectives. Our next step should be to
undertake research on the impact of Internet systems (including
Internet protocols) on human rights, promote the implementation of
protocols good for human rights through policy and advocacy, and
focus on which technical parts we can standardize to help with more
widespread implementation of human-rights-enabling Internet
protocols.
5. Steven M. Bellovin: Governments and Cryptography: The Crypto Wars
5.1. Historical Background
It's not a secret: many governments in the world don't like it when
people encrypt their traffic. More precisely, they like strong
cryptography for themselves but not for others, whether those others
are private citizens or other countries. But the history is longer
and more complex than that.
For much of written history, both governments and individuals used
cryptography to protect their messages. To cite just one famous
example, Julius Caesar is said to have encrypted messages by shifting
letters in the alphabet by 3 [Kahn1996]. In modern parlance, 3 was
the key, and each letter was encrypted with
C[i] = (P[i] + 3) mod 23
(The Latin alphabet of his time had only 23 letters.) Known Arabic
writings on cryptanalysis go back to at least the 8th century; their
sophistication shows that encryption was reasonably commonly used.
In the 9th century, Abū Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī
developed and wrote about frequency analysis as a way to crack
ciphers [Borda2011] [Kahn1996].
In an era of minimal literacy, though, there wasn't that much use of
encryption, simply because most people could neither read nor write.
Governments used encryption for diplomatic messages, and
cryptanalysts followed close behind. The famed Black Chambers of the
Renaissance era read messages from many different governments, while
early cryptographers devised stronger and stronger ciphers
[Kahn1996]. In Elizabethan times in England, Sir Francis
Walsingham's intelligence agency intercepted and decrypted messages
from Mary, Queen of Scots; these messages formed some of the
strongest evidence against her and eventually led to her execution
[Kahn1996].
This pattern continued for centuries. In the United States, Thomas
Jefferson invented the so-called wheel cipher in the late 18th
century; it was reinvented about 100 years later by Étienne Bazeries
and used as a standard American military cipher well into World War
II [Kahn1996]. Jefferson and other statesmen of the late 18th and
early 19th centuries regularly used cryptography when communicating
with each other. An encrypted message was even part of the evidence
introduced in Aaron Burr's 1807 trial for treason [Kerr2020]
[Kahn1996]. Edgar Allan Poe claimed that he could cryptanalyze any
message sent to him [Kahn1996].
The telegraph era upped the ante. In the US, just a year after
Samuel Morse deployed his first telegraph line between Baltimore and
Washington, his business partner, Francis Smith, published a codebook
to help customers protect their traffic from prying eyes [Smith1845].
In 1870, Britain nationalized its domestic telegraph network; in
response, Robert Slater published a more sophisticated codebook
[Slater1870]. On the government side, Britain took advantage of its
position as the central node in the world's international telegraphic
networks to read a great deal of traffic passing through the country
[Headrick1991] [Kennedy1971]. They used this ability strategically,
too -- when war broke out in 1914, the British Navy cut Germany's
undersea telegraph cables, forcing them to use radio; an intercept of
the so-called Zimmermann telegram, when cryptanalyzed, arguably led
to American entry into the war and thence to Germany's defeat. Once
the US entered the war, it required users of international telegraph
lines to deposit copies of the codebooks they used for compression,
so that censors could check messages for prohibited content
[Kahn1996].
In Victorian Britain, private citizens, often lovers, used encryption
in newspapers' personal columns to communicate without their parents'
knowledge. Charles Wheatstone and Charles Babbage used to solve
these elementary ciphers routinely for their own amusement
[Kahn1996].
This pattern continued for many years. Governments regularly used
ciphers and codes, while other countries tried to break them; private
individuals would sometimes use encryption but not often, and rarely
well. But the two World Wars marked a sea change, one that would
soon reverberate into the civilian world.
The first World War featured vast troop movements by all parties;
this in turn required a lot of encrypted communications, often by
telegraph or radio. These messages were often easily intercepted in
bulk. Furthermore, the difficulty of encrypting large volumes of
plaintext led to the development of a variety of mechanical
encryption devices, including Germany's famed Enigma machine. World
War II amplified both trends. It also gave rise to machine-assisted
cryptanalysis, such as the United Kingdom's bombes (derived from an
earlier Polish design) and Colossus machine, and the American's
device for cracking Japan's PURPLE system. The US also used punch
card-based tabulators to assist in breaking other Japanese codes,
such as the Japanese Imperial Navy's JN-25 [Kahn1996] [Rowlett1998].
These developments set the stage for the postwar SIGINT (Signals
Intelligence) environment. Many intragovernmental messages were sent
by radio, making them easy to intercept; advanced cryptanalytic
machines made cryptanalysis easier. Ciphers were getting stronger,
though, and government SIGINT agencies did not want to give up their
access to data. While there were undoubtedly many developments, two
are well known.
The first involved CryptoAG, a Swedish (and later Swiss) manufacturer
of encryption devices. The head of that company, Boris Hagelin, was
a friend of William F. Friedman, a pioneering American cryptologist.
During the 1950s, CryptoAG sold its devices to other governments;
apparently at Friedman's behest, Hagelin weakened the encryption in a
way that let the NSA read the traffic [Miller2020].
The story involving the British is less well-documented and less
clear. When some of Britain's former colonies gained their
independence, the British government gave them captured, war-surplus
Enigma machines to protect their own traffic. Some authors contend
that this was deceptive, in that these former colonies did not
realize that the British could read Enigma-protected traffic; others
claim that this was obvious but that these countries didn't care:
Britain was no longer their enemy; it was neighboring countries they
were worried about. Again, though, this concerned governmental use
of encryption [Kahn1996] [Baldwin2022]. There was still little
private use.
5.2. The Crypto Wars Begin
The modern era of conflict between an individual's desire for privacy
and the government desires to read traffic began around 1972. The
grain harvest in the USSR had failed; since relations between the
Soviet Union and the United States were temporarily comparatively
warm, the Soviet grain company -- an arm of the Soviet government, of
course -- entered into negotiations with private American companies.
Unknown to Americans at the time, Soviet intelligence was
intercepting the phone calls of the American negotiating teams. In
other words, private companies had to deal with state actors as a
threat. Eventually, US intelligence learned of this and came to a
realization: the private sector needed strong cryptography, too, to
protect American national interests [Broad1982] [Johnson1998]. This
underscored the need for strong cryptography to protect American
civilian traffic -- but the SIGINT people were unhappy at the thought
of more encryption that they couldn't break.
Meanwhile, the US was concerned about protecting unclassified data
[Landau2014]. In 1973 and again in 1974, the National Bureau of
Standards (NBS) put out a call for a strong, modern encryption
algorithm. IBM submitted Lucifer, an internally developed algorithm
based on what has become known as a 16-round Feistel network. The
original version used a long key. It seemed quite strong, so NBS
sent it off to the NSA to get their take. The eventual design, which
was adopted in 1976 as the Data Encryption Standard (DES), differed
in some important ways from Lucifer. First, the so-called S-boxes,
the source of the cryptologic strength of DES, were changed, and were
now demonstrably not composed of random integers. Many researchers
alleged that the S-boxes contained an NSA back door. It took nearly
20 years for the truth to come out: the S-boxes were in fact
strengthened, not weakened. Most likely, IBM independently
discovered the attack now known as differential cryptanalysis, though
some scholars suspect that the NSA told them about it. The nonrandom
S-boxes protected against this attack. The second change, though,
was clearly insisted on by the NSA: the key size was shortened, from
Lucifer's 112 bits to DES's 56 bits. We now know that the NSA wanted
a 48-bit key size, while IBM wanted 64 bits; they compromised at 56
bits.
Whitfield Diffie and Martin Hellman, at Stanford University, wondered
about the 56-bit keys. In 1979, they published a paper demonstrating
that the US government, but few others, could afford to build a
brute-force cracking machine, one that could try all 2^56 possible
keys to crack a message. NSA denied tampering with the design; a
Senate investigating committee found that assertion to be correct,
but did not discuss the shortened key length issue.
This, however, was not Diffie and Hellman's greatest contribution to
cryptology. A few years earlier, they had published a paper
inventing what is now known as public key cryptography. (In fact,
public key encryption had been invented a few years earlier at UK
Government Communications Headquarters (GCHQ), but they kept their
discovery classified until 1997.) In 1978, Ronald Rivest, Adi
Shamir, and Leonard Adleman devised the RSA algorithm, which made it
usable. (An NSA employee, acting on his own, sent a letter warning
that academic conferences on cryptology might violate US export
laws.)
Around the same time, George Davida at the University of Wisconsin
applied for a patent on a stream cipher; the NSA slapped a secrecy
order on the application. This barred him from even talking about
his invention. The publicity was devastating; the NSA had to back
down.
The Crypto Wars had thus begun: civilians were inventing strong
encryption systems, and the NSA was tampering with them or trying to
suppress them. Bobby Inman, the then-director of the NSA, tried
creating a voluntary review process for academic papers, but very few
researchers were interested in participating [Landau1988].
There were few major public battles during the 1980s because there
were few new major use cases for civilian cryptography during that
time. There was one notable incident, though: Shamir, Amos Fiat, and
Uriel Feige invented zero-knowledge proofs and applied for a US
patent. In response, the US Army slapped a secrecy order on the
patent. After a great deal of public outrage and intervention by, of
all organizations, the NSA, the order was lifted on very narrow
grounds: the inventors were not American, and they had been
discussing their work all over the world [Landau1988].
In the 1990s, though, everything changed.
5.3. The Battle Is Joined
There were three major developments in cryptography in the early
1990s. First, Phil Zimmermann released PGP (Pretty Good Privacy), a
package to encrypt email messages. In 1993, AT&T planned to release
the TSD-3600, an easy-to-use phone encryptor aimed at business
travelers. Shortly after that, the Netscape Communications
Corporation released SSL (Secure Socket Layer) as a way to enable
web-based commerce using their browser and web server. All of these
were seen as threats by the NSA and the FBI.
PGP was, at least arguably, covered by what was known as ITAR, the
International Trafficking in Arms Regulations -- under American law,
encryption software was regarded as a weapon, so exports required a
license. It was also alleged to infringe the patents on the RSA
algorithm. Needless to say, both issues were problematic for what
was intended to be open source software. Eventually, the criminal
investigation into Zimmermann's role in the spread of PGP overseas
was dropped, but the threat of such investigations remained to deter
others [Levy2001].
The TSD-3600 was another matter. AT&T was a major corporation that
did not want to pick a fight with the US government, but
international business travelers were seen as a major market for the
device. At the government's "request", the DES chip was replaced
with what was known as the Clipper chip. The Clipper chip used
Skipjack, a cipher with 80-bit keys; it was thus much stronger
against brute-force attacks than DES. However, it provided "key
escrow". Without going into any details, the key escrow mechanism
allowed US government eavesdroppers to consult a pair of (presumably
secure) internal databases and decrypt all communications protected
by the chip. The Clipper chip proved to be extremely unpopular with
industry; that AT&T Bell Labs' Matt Blaze found a weakness in the
design [Blaze1994], one that let you use Skipjack without the key
escrow feature, didn't help its reputation.
The third major development, SSL, was even trickier. SSL was aimed
at e-commerce, and of course Netscape wanted to be able to sell its
products outside the US. That would require an export license, so
they made a deal with the government: non-American users would
receive a version that used 40-bit keys, a key length far shorter
than what the NSA had agreed to 20 years earlier. (To get ahead of
the story: there was a compromise mode of operation, wherein an
export-grade browser could use strong encryption when talking to a
financial institution. This hybrid mode led to cryptographic
weaknesses discovered some 20 years later [Adrian2015].)
Technologists and American industry pushed back. The IETF adopted
the Danvers Doctrine, described in [RFC3365]:
| At the 32cd [sic] IETF held in Danvers, Massachusetts during April
| of 1995 the IESG asked the plenary for a consensus on the strength
| of security that should be provided by IETF standards. Although
| the immediate issue before the IETF was whether or not to support
| "export" grade security (which is to say weak security) in
| standards the question raised the generic issue of security in
| general.
|
| The overwhelming consensus was that the IETF should standardize on
| the use of the best security available, regardless of national
| policies. This consensus is often referred to as the "Danvers
| Doctrine".
Then American companies started losing business to their overseas
competitors, who did not have to comply with US export laws. All of
this led to what seemed like a happy conclusion: the US government
drastically loosened its export rules for cryptographic software.
All was well -- or so it seemed...
5.4. The Hidden Battle
Strong cryptography was here to stay, and it was no longer an
American monopoly, if indeed it ever was. The Information Assurance
Directorate of the NSA, the part of the agency that is supposed to
protect US data, was pleased by the spread of strong cryptography.
When the Advanced Encryption Standard (AES) competition was held,
there were no allegations of malign NSA interference; in fact, the
winning entry was devised by two Europeans, Joan Daemen and Vincent
Rijmen. But the NSA and its SIGINT needs did not go away -- the
agency merely adopted other techniques.
I have often noted that one doesn't go through strong security, one
goes around it. When strong encryption became more common and much
more necessary, the NSA started going around it, by targeting
computers and the software that they run. And it seems clear that
they believe that AES is quite strong; they've even endorsed its use
for protecting TOP SECRET information. But there was an asterisk
attached to that endorsement: AES is suitable if and only if properly
used and implemented. Therein lies the rub.
The first apparent attempt to tamper with outside cryptographic
mechanisms was discovered in 2007, when two Microsoft researchers,
Dan Shumow and Niels Ferguson, noted an odd property of a NIST-
standardized random number generator, DUAL_EC_DRBG. (The NBS had
been renamed to NIST, the National Institute of Standards and
Technology.) Random numbers are vital for cryptography, but Shumow
and Ferguson showed that if certain constants in DUAL_EC_DRBG were
chosen in a particular way with a known-but-hidden other number,
whoever knew that number could predict all future random numbers from
a system given a few sample bytes to start from [Kostyuk2022]. These
sample bytes could come from known keys, nonces, or anything else.
Where did the constants in DUAL_EC_DRBG come from and how were they
chosen or generated? No one who knows is talking. But although
cryptographers and security specialists were very suspicious -- Bruce
Schneier wrote in 2007, before more facts came out, that "both NIST
and the NSA have some explaining to do"; I assigned my students
reading on the topic -- the issue didn't really get any traction
until six years later, when among the papers that Edward Snowden
disclosed was the information that the NSA had indeed tampered with a
major cryptographic standard, though published reports did not
specifically name DUAL_EC_DRBG or explain what the purpose was.
The revelations didn't stop there. There have been allegations that
the NSA paid some companies to use DUAL_EC_DRBG in their products.
Some people have claimed that there were attempts to modify some IETF
standards to make enough random bytes visible, to aid in exploiting
the random number generator. A major vendor of networking gear,
Juniper, did use DUAL_EC_DRBG in some of its products, but with
different constants [Checkoway2016]. Where did these come from?
Were they from the NSA or some other government? Could their source
tree have been hacked by an intelligence agency? There was a
different hack of their code at around the same time [Moore2015]. No
one is talking.
The Snowden revelations also included data suggesting that the NSA
had a worldwide eavesdropping network and a group that tried very
specific, targeted hacks on very specific targets' systems. In
retrospect, neither is surprising: "spies gonna spy". The NSA's
business is signals intelligence; of course they're going to try to
intercept traffic. Indeed, the DUAL_EC_DRBG tampering is useless to
anyone who has not collected messages to decrypt. And targeted hacks
are a natural way around strong encryption: collect the data before
it is encrypted or after it is decrypted, and don't worry about the
strength of the algorithms.
The privacy community, worldwide, was appalled, though perhaps they
shouldn't have been. It calls to mind the line that Claude Rains'
character uttered in the movie Casablanca [Curtiz]: "I'm shocked,
shocked to find that gambling is going on in here." The immediate
and continuing reaction was to deploy more encryption. The standards
have long existed; what was missing was adoption. One barrier was
the difficulty and expense of getting certificates to use with TLS,
the successor to SSL; that void was filled by Let's Encrypt [LE],
which made free certificates easy to get online. Today, most HTTP
traffic is encrypted, so much so that Google's search engine down-
ranks sites that do not use it. Major email providers uniformly use
TLS to protect all traffic. Wi-Fi, though a local area issue, now
uses much stronger encryption. (It's important to remember that
security and insecurity have economic components. Security doesn't
have to be perfect to be very useful, if it raises the attackers'
costs by enough.)
The news on the software side is less good. Not a day goes by when
one does not read of organizations being hit by ransomware. It goes
without saying that any threat actor capable of encrypting disks is
also capable of stealing the information on them; indeed, that is a
frequent accompanying activity, since the threat of disclosure is
another incentive to pay for those sites that do have good enough
backups. Major vendors have put a lot of effort into securing their
software, but bugs and operational errors by end-user sites persist.
5.5. Whither the IETF?
Signal intelligence agencies, not just the NSA, but its peers around
the globe -- most major countries have their own -- are not going to
go away. The challenges that have beset the NSA are common to all
such agencies, and their solutions are likely the same. The question
is what should be done to protect individual privacy. A number of
strong democracies, such as Australia and the United Kingdom, are, in
a resumption of the Crypto Wars, moving to restrict encryption.
Spurred on by complaints from the FBI and other law enforcement
agencies, the US Congress frequently considers bills to do the same.
The IETF has long had a commitment to strong, ubiquitous encryption.
This is a good thing. It needs to continue, with cryptography and
other security features designed into protocols from the beginning.
But there is also a need for maintenance. Parameters such as key
lengths and modulus sizes age; a value that is acceptable today may
not be 10 years hence. (We've already seen apparent problems from
1024-bit moduli specified in an RFC, an RFC that was not modified
when technology improved enough that attacking encryption based on
them had become feasible [Adrian2015].) The IETF can do nothing
about the code that vendors ship or that sites use, but it can alert
the world that it thinks things have changed.
Cryptoagility is of increasing importance. In the next very few
years, we will have so-called post-quantum algorithms. Both
protocols and key lengths will need to change, perhaps drastically.
Is the IETF ready? What will happen to, say, DNSSEC if key lengths
become drastically longer? Backwards compatibility will remain
important, but that, of course, opens the door to other attacks.
We've long thought about them; we need to be sure that our mechanisms
work -- we've been surprised in the past [BellovinRescorla2006].
We also need to worry more about metadata. General Michael Hayden,
former director of both the NSA and the CIA, once remarked, "We kill
people based on metadata" [Ferran2014]. But caution is necessary;
attempts to hide metadata can have side effects. To give a trivial
example, Tor is quite strong, but if your exit node is in a different
country than you are in, web sites that use IP geolocation may
present their content in a language foreign to you. Some sites even
block connections from known Tor exit nodes. More generally, many
attempts to hide metadata involve trusting a different party; that
party may turn out to be untrustworthy or it may itself become a
target of attack. As another prominent IETFer has remarked,
"Insecurity is like entropy; you can't destroy it, but you can move
it around." The IETF has done a lot; it needs to do more. And
remember that the risk here is not just governments acting directly,
it's also private companies that collect the data and sell it to all
comers.
Finally, the IETF must remember that its middle name is
"Engineering". To me, one of the attributes of engineering is the
art of picking the right solution in an over-constrained environment.
Intelligence agencies won't go away, nor will national restrictions
on cryptography. We have to pick the right path while staying true
to our principles.
6. Security Considerations
Each or any of the authors may have forgotten or omitted things or
gotten things wrong. We're sorry if that's the case, but that's in
the nature of a look-back such as this. Such flaws almost certainly
won't worsen security or privacy, though.
7. IANA Considerations
This document has no IANA actions.
8. Informative References
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[LE] Aas, J., Barnes, R., Case, B., Durumeric, Z., Eckersley,
P., Flores-López, A., Halderman, A., Hoffman-Andrews, J.,
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Networks", Work in Progress, Internet-Draft, draft-ietf-
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IETF", IETF 88 Proceedings, November 2013,
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Engineering Task Force", November 2013,
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[Refs-to-7258]
IETF, "References to RFC7258",
<https://datatracker.ietf.org/doc/rfc7258/referencedby/>.
[RFC1984] IAB and IESG, "IAB and IESG Statement on Cryptographic
Technology and the Internet", BCP 200, RFC 1984,
DOI 10.17487/RFC1984, August 1996,
<https://www.rfc-editor.org/info/rfc1984>.
[RFC3365] Schiller, J., "Strong Security Requirements for Internet
Engineering Task Force Standard Protocols", BCP 61,
RFC 3365, DOI 10.17487/RFC3365, August 2002,
<https://www.rfc-editor.org/info/rfc3365>.
[RFC6462] Cooper, A., "Report from the Internet Privacy Workshop",
RFC 6462, DOI 10.17487/RFC6462, January 2012,
<https://www.rfc-editor.org/info/rfc6462>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>.
[RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 7480, DOI 10.17487/RFC7480, March 2015,
<https://www.rfc-editor.org/info/rfc7480>.
[RFC7481] Hollenbeck, S. and N. Kong, "Security Services for the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 7481, DOI 10.17487/RFC7481, March 2015,
<https://www.rfc-editor.org/info/rfc7481>.
[RFC7687] Farrell, S., Wenning, R., Bos, B., Blanchet, M., and H.
Tschofenig, "Report from the Strengthening the Internet
(STRINT) Workshop", RFC 7687, DOI 10.17487/RFC7687,
December 2015, <https://www.rfc-editor.org/info/rfc7687>.
[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "Specification for DNS over Transport
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
2016, <https://www.rfc-editor.org/info/rfc7858>.
[RFC8056] Gould, J., "Extensible Provisioning Protocol (EPP) and
Registration Data Access Protocol (RDAP) Status Mapping",
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<https://www.rfc-editor.org/info/rfc8056>.
[RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu,
"Recommendation on Stable IPv6 Interface Identifiers",
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[RFC8280] ten Oever, N. and C. Cath, "Research into Human Rights
Protocol Considerations", RFC 8280, DOI 10.17487/RFC8280,
October 2017, <https://www.rfc-editor.org/info/rfc8280>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8461] Margolis, D., Risher, M., Ramakrishnan, B., Brotman, A.,
and J. Jones, "SMTP MTA Strict Transport Security (MTA-
STS)", RFC 8461, DOI 10.17487/RFC8461, September 2018,
<https://www.rfc-editor.org/info/rfc8461>.
[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/info/rfc8484>.
[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981,
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[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
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[RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access
Protocol (RDAP) Query Format", STD 95, RFC 9082,
DOI 10.17487/RFC9082, June 2021,
<https://www.rfc-editor.org/info/rfc9082>.
[RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the
Registration Data Access Protocol (RDAP)", STD 95,
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<https://www.rfc-editor.org/info/rfc9083>.
[RFC9113] Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
DOI 10.17487/RFC9113, June 2022,
<https://www.rfc-editor.org/info/rfc9113>.
[RFC9224] Blanchet, M., "Finding the Authoritative Registration Data
Access Protocol (RDAP) Service", STD 95, RFC 9224,
DOI 10.17487/RFC9224, March 2022,
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Acknowledgments
Susan Landau added many valuable comments to Steve Bellovin's essay.
We thank Carsten Bormann, Brian Carpenter, Wendy Grossman, Kathleen
Moriarty, Jan Schaumann, Seth David Schoen, and Paul Wouters for
comments and review of this text, though that of course doesn't mean
that they necessarily agree with the text.
This document was created at the behest of Eliot Lear, who also cat
herded and did some editing.
Authors' Addresses
Stephen Farrell
Trinity College, Dublin
Ireland
Email: stephen.farrell@cs.tcd.ie
Farzaneh Badii
Digital Medusa
Email: farzaneh.badii@gmail.com
Bruce Schneier
Harvard University
United States of America
Email: schneier@schneier.com
Steven M. Bellovin
Columbia University
United States of America
Email: smb@cs.columbia.edu