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Ian Brown <I.Brown@cs.ucl.ac.uk> writes:
William Geiger wrote:
This is a stereotypical Strawman. "Even if PGP avoids GAK some other 3rd party can modify it to be Gakware." Every version of PGP had the ability to encrypt to multiple recipients. As I stated in my previous posts I can get PGP 2.6.x to do everything 5.5 does with a couple of scripts.
Yes, but as Adam says, the average Mr. Windows can not. In any case, this is not a narrow technical argument. Of course any system with multiple recipients can be turned into GAKware. The point is that we don't want to make it ANY easier for anyone to do so.
Agree. What I am proposing is to make GAK enabled systems non-interoperable with the OpenPGP standard on the sending end (ie to define that when you receive a message it won't dictate to you that you should use GAK compliancy, and to define that if flags indicating message snooping is ocurring this won't be enforced by your mail being bounced if you don't, and won't be implemented with encrypting to a special snooping crypto recipient). What PGP is proposing with PGP 5.5 is to implement enforcement on end users to send to GAK (or corporate snooping) enabled keys using the snooping key. They claim that it's ok, because the user is empowered, as he can override the sending to the snooping key. But, if you enable the sender of a message you receive to state (in syntax defined as part of the OpenPGP standard, or even if it is not) that if you don't encrypt to this corporate snooping key (or technically equivalent functionality: government GAKking key) the message will bounce, how is this user empowerment, or choice in any meaningful way. How is this user empowered to choose when 80% of businesses end up using this feature? Or when the government mandates this feature.
No this is not mandatory GAK compliance. Mandatory GAK compliance would be if every copy of PGP came with a government key and the program *forced* the user to encrypt all his messages with it.
Again, as Adam says, how long would it take for a government to introduce legislation making this mandatory once PGP 5.5-type systems took off? Or, more insiduously, using its purchasing power - "Federal agencies will only buy CAK-enabled systems" - to ensure the vast majority of systems did so.
Bingo!
Ok Adam here is a challenge for you:
-- Explain why Corporations do not have the right to access *their* documents in whatever form they may be in.
Can I take this one up ;-)
You beat me to it ... my reply crossed in the mail :-)
The point is, with *communication* keys, corporations will have full access to the plaintext because it will be decrypted by the recipient as soon as it arrives. I appreciate your point about corporations being able to read *their* documents - although doing so by snooping, without the sender's knowledge, is rather unethical to say the least - but I don't think they have the right to snoop on all *incoming* communications, whoever they may be from. This is the really scary part of PGP 5.5...
Even if you do argue that they do have the right to snoop incoming messages (and there may be a case for this even if some of us find it a bit little brotherish), this can still be just as easily catered for, without building GAK compliance into the IETF OpenPGP standard by having the user's client software decrypt and store their mail folder in plain text, or encrypted to a company escrowed storage key. Such a system would not be at all GAK compliant.
William Simpson wrote:
Let us decide _what_ the goals are, _how_ to solve the problems, and _then_ decide the protocol details and formats to match the solution.
Absolutely. Can we start with Adam and William's proposal that we should have three separate types of key: communication, signature, and storage.
(I am glad that you managed to persuade William that this was necessary, I didn't notice him agree :-) William should however be credited for the useful contribution that you can just as easily implement corporate snooping with the existing multiple crypto recipients functions of pgp2.x. (Without the GAK compliancy baggage).
This would be very simple to implement; probably the easiest and most backward-compatible way would be to define a new packet type specifying a key's usage.
I'll go for this idea. X509 v3 certificates have such an extension, and it seems like a very useful functionality for OpenPGP to include. Re. the argument about separating key functionality leading to more consistent and secure designs, if people don't like 3 keys, you should see some of the Norwegian standards stuff which was relayed to me at a eurpean medical messaging standarisation meeting... they reportedly have 5 key usages defined: 1. storage 2. signatures 3. encryption 4. certificates 5. authentication
Why have a communication enforcement filter, when the only usage is supposed to be for recovering archival storage?
Absolutely. I can see the point, and appreciate the difficulties faced by PGP Inc., in most of the CAK features of PGP 5.5. But I just can *not* see how the twisted idea of the SMTP snooper ever came about.
It came about I suspect because the real unstated feature they are trying to implement is message snooping, and not stored email folder access as the "data recovery" badge used by Jon in his first post may lead one to assume. Of course the reason they think they are able to use the argument that "email is both storage and communications" to justify this is largely because they haven't yet digested the meme that you should have separate storage keys. I also heartily agree with William Allen Simpson's comments. Adam -- Now officially an EAR violation... Have *you* exported RSA today? --> http://www.dcs.ex.ac.uk/~aba/rsa/ print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<> )]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`