This proposal to register keys was also mentioned in the July, 1992 Communications of the ACM, in an article by Ron Rivest, one of the creators of the RSA algorithm. He was mostly criticizing the proposed government Digital Signature Standard, stating that he thought that the NSA was purposely trying to get "weak" cryptography installed as the standard. Then he goes on to say, "Are there technical alternatives that would satisfy all parties? Perhaps. It is certainly the case that the formulation of the problem to be solved has never been made explicit for the cryptographic community to work on. I suspect that a solution based on 'escrowed secret keys' might be workable, wherein each user is legally required to depost his or her secret key with a trusted third party, such as the user's bank. Cryptographic hardware and software would only operate with public keys that were certified to having their corres- ponding secret keys appropriately escrowed. A federal agency could then obtain the secret key, or its use, with an appropriate warrant. Once their secret keys were escrowed, multinational corporations could even operate across borders with a high degree of authentication and privacy (except perhaps from court-ordered wiretaps). Cryptographic hardware and software manufactured in the U.S. would not operate abroad without public keys suitably certified as having their secret counterparts escrowed in the U.S. In an extension of this approach, users can escrow their secret keys with several trusted third parties in a 'secret-sharing' manner, so that no single third party can com- promise the user's key. While this approach may have its own difficulties, it does illustrate that weak cryptography is not the only technical approach available. There may be much better techniques for achieving a compromise between a number of conflicting national concerns." At the time that I read this, I thought it was largely a rhetorical device, making the point that if the government wants to infringe on people's privacy, it should come out in the open and do so, rather than skulking about. (Like saying, "if the government _really_ wants to stop sexual immorality it would have to put a TV camera in every bedroom".) And of course (I thought) this kind of proposal would never be taken seriously. I'm shocked that Denning is now advocating it openly. This proposal makes it illegal for people to communicate so secretly that the government can't find out what they are saying. It could apply to postal mail as well as email - it would be illegal to send a message via post which the government couldn't interpret. If this is really the government's purpose, then it should also require that all private conversations be recorded, and the resulting tapes be "escrowed" similarly in case the government needed to find out what was said, for which it would have to get a court order. As Tim suggested, this is probably a "trial balloon" being floated to see what the reaction is. Let's see that it gets shot down. Hal 74076.1041@compuserve.com