+ + Cypherpunks don't care if you don't like the + software they write. Cypherpunks know that + software can't be destroyed. Cypherpunks know + that a widely dispersed system can't be shut + down. + -- the cypherpunk manifesto + (cypherpunks-request@toad.com) ++++++++++++++++++++++++++++++++++++++++++++++++ Here's a short piece from Scientific American on RSA, PEM, PGP etc. Notice towards the end this article says "The U.S. is the only nation that permits the patenting of mathematical algorithms." That threw me at first -- it's not *supposed* to be permitted, but in practice, it is. So I suppose this is a true statement. (The cover article of this Sci Am is on a team at the Science Museum in London that did a 3-ton implementation of Babbage's Difference Engine.) -- strick ________________________________________________________________________ ________________________________________________________________________ Source: Scientific American, February 1993, beginning at the 30th page. For fair use only. Electronic Envelopes? The uncertainty of keeping e-mail private Recent legislative efforts to mandate remote wiretapping attachments for every telephone system and computer network in the U.S. may have been the best thing that every happened for encryption software. "We have mostly the FBI to thank," says John Gilmore of Cygnus Support in Palo Alto, Calif. Gilmore is an entrepreneur, hacker and electronic civil libertarian who helped to found the Electronic Frontier Foundation (EFF). He is now watching closely the development of two competing techniques for keeping electronic mail private. As matters now stand, computers transmit messages from one user to another in plain text. If a geneticist in Boston sends e-mail to a molecular biologist in San Diego, any of the half a dozen or so intermediary machines that forward the letter could siphon off a copy -- and so could any of the dozens of workstations that might be attached to the local-area network at the sender's or recipient's university or company. The Electronic Privacy Act of 1986 prohibits snooping by public e-mail carriers or law-enforcement officials, except by court order. Nevertheless, many people are becoming uncomfortable with the electronic equivalent of mailing all their correspondence on postcards and relying on people to refrain from reading it. They are turning to public-key encryption, which allows anyone to encode a message but only the recipient to decode it. Each user has a public key, which is made widely available, and a closely guarded secret key. Messages encrypted with one key can be decrypted only with each other, thus also making it possible to "sign" messages by encrypting them with the private key [see "Achieving Electronic Privacy," by David Chaum; Scientific American, August 1992]. Two programs -- and two almost diametrically opposed viewpoints embodied in them -- are competing for acceptance. Privacy Enhanced Mail (PEM) is the long-awaited culmination of years of international standard setting by computer scientists. Pretty Good Privacy (PGP) is a possibly illegal work of "guerilla freeware" originally written by software consultant Philip Zimmermann. The philosophies of PEM and PGP differ most visibly with respect to key management, the crucial task of ensuring that the public keys that encode messages actually belong to the intended recipient rather than a malevolent third party. PEM relies on a rigid hierarchy of trusted companies, universities and other institutions to certify public keys, which are then stored on a "key server" accessible over the Internet. To send private mail, one asks the key server for the public key of the addressee, which has been signed by the appropriate certification authorities. PGP, in contrast, operates on what Zimmermann calls "a web of trust": people who wish to correspond privately can exchange keys directly or through trusted intermediaries. The intermediaries sign the keys that they pass on, thus certifying their authenticity. PGP's decentralized approach has gained a wide following since its initial release in June 1991, according to Hugh E. Miller of Loyola University in Chicago, who maintains an electronic mailing list for discussion among PGP users. His personal "keyring" file contains public keys for about 100 correspondents, and others have keyrings containing far more. As of the end of 1992, meanwhile, a final version of PEM has not been officially released. Gilmore, who subscribes to the electronic mailing list for PEM developers, says he has seen "only five or 10" messages actually encrypted using the software. Although PGP's purchase price is right -- it is freely available over the Internet and on electronic bulletin boards throughout the world -- it does carry two liabilities that could frighten away potential users. First, U.S. law defines cryptographic hardware and software as "munitions." So anyone who is caught making a copy of the program could run afoul of export-control laws. Miller calls this situation "absurd," citing the availability of high-quality cryptographic software on the streets of Moscow. Worse yet, RSA Data Security in Redwood City, Calif., holds rights to a U.S. patent on the public-key encryption algorithm, and D. James Bidzos, the company's president, asserts that anyone using or distributing PGP could be sued for infringement. The company has licensed public-key software to corporations and sells its own encrypted-mail package (the algorithm was developed with federal support, and so the government has a royalty-free license). When Bidzos's attorneys warned Zimmermann that he faced a suit for developing PGP, he gave up further work on the program. Instead PGP's ongoing improvements are in the hands of an international team of software developers who take advice from Zimmermann by e-mail. The U.S. is the only nation that permits the patenting of mathematical algorithms, and so programmers in the Netherlands or New Zealand apparently have little to fear. U.S. residents who import the program could still face legal action, although repeated warnings broadcast in cryptography discussion groups on computer networks have yet to be superseded by legal filings. Meanwhile, Gilmore says, the only substantive effect of the patent threat is that development and use of cryptographic tools have been driven out of the U.S. into less restrictive countries -- Paul Wallich ________________________________________________________________________ ________________________________________________________________________ The SURFPUNK Technical Journal is a dangerous multinational hacker zine originating near BARRNET in the fashionable western arm of the northern California matrix. Quantum Californians appear in one of two states, spin surf or spin punk. Undetected, we are both, or might be neither. ________________________________________________________________________ Send postings to , subscription requests to . MIME encouraged. Xanalogical archive access soon. Cypherpunks love to practice. ________________________________________________________________________ ________________________________________________________________________ #define DA_MD2 3 #define DA_MD5 5 #define MIN_RSA_MODULUS_BITS 508 #define MAX_RSA_MODULUS_BITS 1024 #define MAX_RSA_MODULUS_LEN ((MAX_RSA_MODULUS_BITS + 7) / 8) #define MAX_RSA_PRIME_BITS ((MAX_RSA_MODULUS_BITS + 1) / 2) #define MAX_RSA_PRIME_LEN ((MAX_RSA_PRIME_BITS + 7) / 8)