5 ms·

Battle of the Clipper Chip (1994)

65 points by Cieplak 9y ago

pmoriarty 9y ago
How does the Clipper Chip compare to more modern technologies like the Intel Management Engine?
- schoen 9y ago
  They have very little in common. The Clipper Chip was designed by the government to be used in phones in order to give people communications security—but not too much communications security against government entities—and to pre-empt and outcompete other cryptographic voice privacy solutions that people might want to adopt. The IME is designed by Intel to allow remote management of PCs. It creates risks of unauthorized access to those computers, including by increasing the attack surface outside of (one might say "beneath") ordinary operating system security features. I guess the parallel is that both are hardware-implemented device functionality that many users might not want and that could expose their data to risks they don't appreciate.
- excitom 9y ago
  "Cryptography is the silver bullet by which we can hope to reclaim our privacy. The solution, however, has one drawback: cryptography shields the law abiding and the lawless equally. Law-enforcement and intelligence agencies contend that if strong codes are widely available, their efforts to protect the public would be paralyzed. So they have come up with a compromise, a way to neutralize such encryption. That's the Clipper chip and that compromise is what the war is about." So there it is, a government-mandated encryption device that has a backdoor built in. The IME is a well-intended system management feature that can be turned to nefarious purposes since it can go around all operating system security features, e.g. read or update all of the system's memory.
  - jacobush 9y ago
    The Clipper Chip was also well intended. It's just that it put the emphasis of trust somewhere most of us are not happy with.
  - Nullabillity 9y ago
    If the IME was well-intentioned then it would have been easy to disable, and the source code would have been public.
    - pjc50 9y ago
      Firmware is never public, it's just proprietary code. Closedness tells us almost nothing about intent.
deleted 9y ago
[deleted]
oceanghost 9y ago
This article only hints at what was well known at the time-- that this was simply the first step in an attempt to outlaw cryptography altogether. The next step was to either pass a law requiring key disclosure, our outlaw cryptography alltoegether. If you think that sounds far fetched... remember at the time this article was written they were trying to jail Phill Zimmerman for writing PGP.
- Fnoord 9y ago
  Seems many EU and FVEY countries went with the key disclosure laws [1]. [1] https://en.wikipedia.org/wiki/Key_disclosure_law https://en.wikipedia.org/wiki/Key_disclosure_law
- delinka 9y ago
  "...they were trying to jail Phill Zimmerman for writing PGP." Writing it or exporting it? Sure, their motivations may have been due to the former (is there even documentation for that?), but IIRC the technical reason was that, because it'd been made available online for anyone on the planet to download, they tried to pin "export of munitions" on Phil.
  - oceanghost 9y ago
    What method would you propose could be used to allow only US citizens to use a piece of software? The law is pretty damn clear. Create strong encryption, go to jail.
    - delinka 9y ago
      It's not the author's job to prevent use of his software by specific individuals as deemed by the US government. It is, however, any citizen's responsibility not to break the law by sending or carrying stuff outside the US. And indeed, the law is pretty clear: export "munitions" (according to a list - at the time "strong encryption" was on the list) and you'll feel the wrath of Uncle Sam. But they dropped their case against Zimmerman. Never filed charges. Probably because there was no evidence that he was the one to export PGP.
Cieplak 9y ago
Thought it was interesting that plans for the Clipper Chip were canceled around the time the recently discovered CPU vulnerabilities were introduced. Extremely unlikely that there was some conspiracy given the number of vendors affected, but a possibility given the magnitude of the military budget and the value of being able to decrypt enemy communications via side-channel attacks.
- Fnoord 9y ago
  Does SELinux mitigate Meltdown and/or Spectre?
  - pjc50 9y ago
    No, it's just a (hard to use) capability system.
pjc50 9y ago
Operation of Clipper: http://www.crypto.com/papers/escrow-acsac11.pdf http://www.crypto.com/papers/escrow-acsac11.pdf "Clipper was intended as a drop- in replacement for a standard DES chip, but with a new symmetric-key cipher algorithm, called Skipjack , designed by the National Security Agency and using an 80 bit key. But before any two Clipper chips could communicate, they would first exchange a Law Enforcement Access Field (LEAF) that contained a copy of the current session key, itself en- crypted with an “escrowed” Unit Key held by the govern- ment. Any Clipper-encrypted communication could thus be decrypted by government agents without needing to break the (presumably strong) Skipjack cipher. The agents would be able to recover the session key simply by decrypting the copy in the LEAF (which they would intercept along with the ciphertext) using their escrowed copy of the unit key" It had a fatal flaw: a 16-bit checksum that could be brute-forced.
corysama 9y ago
The documentary “The Century of the Self” has a section on the Clipper chip. It showed video of a Clinton campaign manager explaining to volunteers that “Yeah, we know this is stupid, but it’s an important part of our message that we are here to protect your children.” The documentary is excellent all around. Highly recommended. Possibly available on YouTube.
- Fnoord 9y ago
  That's a documentary by Adam Curtis [0]. Various of his documentaries are generally available on Archive.org, including this one. Its 4 parts [1] [2] [3] [4]. I've seen The Power Of Nightmares and The Century Of The Self. Both highly recommended though I didn't remember Clipper chip was mentioned. [0] https://en.wikipedia.org/wiki/Adam_Curtis https://en.wikipedia.org/wiki/Adam_Curtis [1] https://archive.org/details/TheCenturyOfTheSelfPart1 https://archive.org/details/TheCenturyOfTheSelfPart1 [2] https://archive.org/details/TheCenturyOfTheSelfPart2 https://archive.org/details/TheCenturyOfTheSelfPart2 [3] https://archive.org/details/TheCenturyOfTheSelfPart3 https://archive.org/details/TheCenturyOfTheSelfPart3 [4] https://archive.org/details/TheCenturyOfTheSelfPart4 https://archive.org/details/TheCenturyOfTheSelfPart4

65 points by Cieplak 9y ago

pmoriarty 9y ago

How does the Clipper Chip compare to more modern technologies like the Intel Management Engine?

schoen 9y ago
They have very little in common. The Clipper Chip was designed by the government to be used in phones in order to give people communications security—but not too much communications security against government entities—and to pre-empt and outcompete other cryptographic voice privacy solutions that people might want to adopt. The IME is designed by Intel to allow remote management of PCs. It creates risks of unauthorized access to those computers, including by increasing the attack surface outside of (one might say "beneath") ordinary operating system security features. I guess the parallel is that both are hardware-implemented device functionality that many users might not want and that could expose their data to risks they don't appreciate.
excitom 9y ago
"Cryptography is the silver bullet by which we can hope to reclaim our privacy. The solution, however, has one drawback: cryptography shields the law abiding and the lawless equally. Law-enforcement and intelligence agencies contend that if strong codes are widely available, their efforts to protect the public would be paralyzed. So they have come up with a compromise, a way to neutralize such encryption. That's the Clipper chip and that compromise is what the war is about." So there it is, a government-mandated encryption device that has a backdoor built in. The IME is a well-intended system management feature that can be turned to nefarious purposes since it can go around all operating system security features, e.g. read or update all of the system's memory.
- jacobush 9y ago
  The Clipper Chip was also well intended. It's just that it put the emphasis of trust somewhere most of us are not happy with.
- Nullabillity 9y ago
  If the IME was well-intentioned then it would have been easy to disable, and the source code would have been public.
  - pjc50 9y ago
    Firmware is never public, it's just proprietary code. Closedness tells us almost nothing about intent.

deleted 9y ago

[deleted]

oceanghost 9y ago

This article only hints at what was well known at the time-- that this was simply the first step in an attempt to outlaw cryptography altogether. The next step was to either pass a law requiring key disclosure, our outlaw cryptography alltoegether. If you think that sounds far fetched... remember at the time this article was written they were trying to jail Phill Zimmerman for writing PGP.

Fnoord 9y ago
Seems many EU and FVEY countries went with the key disclosure laws [1]. [1] https://en.wikipedia.org/wiki/Key_disclosure_law https://en.wikipedia.org/wiki/Key_disclosure_law
delinka 9y ago
"...they were trying to jail Phill Zimmerman for writing PGP." Writing it or exporting it? Sure, their motivations may have been due to the former (is there even documentation for that?), but IIRC the technical reason was that, because it'd been made available online for anyone on the planet to download, they tried to pin "export of munitions" on Phil.
- oceanghost 9y ago
  What method would you propose could be used to allow only US citizens to use a piece of software? The law is pretty damn clear. Create strong encryption, go to jail.
  - delinka 9y ago
    It's not the author's job to prevent use of his software by specific individuals as deemed by the US government. It is, however, any citizen's responsibility not to break the law by sending or carrying stuff outside the US. And indeed, the law is pretty clear: export "munitions" (according to a list - at the time "strong encryption" was on the list) and you'll feel the wrath of Uncle Sam. But they dropped their case against Zimmerman. Never filed charges. Probably because there was no evidence that he was the one to export PGP.

Cieplak 9y ago

Thought it was interesting that plans for the Clipper Chip were canceled around the time the recently discovered CPU vulnerabilities were introduced. Extremely unlikely that there was some conspiracy given the number of vendors affected, but a possibility given the magnitude of the military budget and the value of being able to decrypt enemy communications via side-channel attacks.

Fnoord 9y ago
Does SELinux mitigate Meltdown and/or Spectre?
- pjc50 9y ago
  No, it's just a (hard to use) capability system.

pjc50 9y ago

Operation of Clipper: http://www.crypto.com/papers/escrow-acsac11.pdf http://www.crypto.com/papers/escrow-acsac11.pdf "Clipper was intended as a drop- in replacement for a standard DES chip, but with a new symmetric-key cipher algorithm, called Skipjack , designed by the National Security Agency and using an 80 bit key. But before any two Clipper chips could communicate, they would first exchange a Law Enforcement Access Field (LEAF) that contained a copy of the current session key, itself en- crypted with an “escrowed” Unit Key held by the govern- ment. Any Clipper-encrypted communication could thus be decrypted by government agents without needing to break the (presumably strong) Skipjack cipher. The agents would be able to recover the session key simply by decrypting the copy in the LEAF (which they would intercept along with the ciphertext) using their escrowed copy of the unit key" It had a fatal flaw: a 16-bit checksum that could be brute-forced.

corysama 9y ago

The documentary “The Century of the Self” has a section on the Clipper chip. It showed video of a Clinton campaign manager explaining to volunteers that “Yeah, we know this is stupid, but it’s an important part of our message that we are here to protect your children.” The documentary is excellent all around. Highly recommended. Possibly available on YouTube.

Fnoord 9y ago
That's a documentary by Adam Curtis [0]. Various of his documentaries are generally available on Archive.org, including this one. Its 4 parts [1] [2] [3] [4]. I've seen The Power Of Nightmares and The Century Of The Self. Both highly recommended though I didn't remember Clipper chip was mentioned. [0] https://en.wikipedia.org/wiki/Adam_Curtis https://en.wikipedia.org/wiki/Adam_Curtis [1] https://archive.org/details/TheCenturyOfTheSelfPart1 https://archive.org/details/TheCenturyOfTheSelfPart1 [2] https://archive.org/details/TheCenturyOfTheSelfPart2 https://archive.org/details/TheCenturyOfTheSelfPart2 [3] https://archive.org/details/TheCenturyOfTheSelfPart3 https://archive.org/details/TheCenturyOfTheSelfPart3 [4] https://archive.org/details/TheCenturyOfTheSelfPart4 https://archive.org/details/TheCenturyOfTheSelfPart4