[net.crypt] Public Key Crypto-Systems

mcg@aat.UUCP (11/30/83)

Could someone give me a reference (or even better, *code*, or an
algorithm description) for a public-key encryption system. To the
best of my knowledge, these systems are based on the distribution
of very large pseudo-prime numbers, i.e. large numbers with
exactly two large prime factors. The psuedo-prime can be distributed
in a "phonebook", but the factors are kept secret. The sender
encrypts the outgoing message using the pseudo-prime, but the factors
are required to decode it.  It has a side benefit of unforgeably
identifying the sender of any given message.  I am interested in
implementing one such system for UNIX.

The National Security Agency has been trying to supress scholarly
discussion on this topic, reportedly because this is an encryption
system that even they do not have the resources to break (unlike DES).
[This from the recent book, "The Puzzle Palace"].

S. McGeady
cbosg!cbosgd!aat!mcg
tektronix!psu-cs!aat!mcg

mark@umcp-cs.UUCP (12/03/83)

Berkeley Unix already has a public key encryption system used
to send secret mail.  It is called xsend and xget, and has been
around for several years at least.  (I don't know if
it originated at Bell or not--all I know it is here on our vax.)

Secret mail to each person is encrypted with their public key and
kept in a spool directory, but then can of course only be read
by that person themselves, who is the only holder of the private key.
-- 
spoken:	mark weiser
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!mark
CSNet:	mark@umcp-cs
ARPA:	mark.umcp-cs@CSNet-Relay

smb@ulysses.UUCP (12/10/83)

Folks interested in a technical introduction to cryptography should start
with the December, 1979 issue of Computing Surveys.  Among other things,
it has pointers to things like Rivest, Shamir, and Adelson's paper in CACM
on their public-key cryptosystem.  Folks interested in a non-technical
introduction should read David Kahn's "The Codebreakers", preferably the
hard-cover edition.

bae@astrovax.UUCP (Brian Ehrmantraut ) (12/10/83)

	A good introductory book is :

		Cryptography and Data Security, Dorothy E. R. Denning,
		Addison-Wesley, 1983


			Brian Ehrmantraut
			allegra!{fisher, astrovax, twiggy}!bae