Eric Blossom <eb@comsec.com> (CSC) writes:
Communication Security Corporation CS8191 Triple-DES Telephone Privacy Device [...] Specifications:
Modem
* ITU V.32bis (14,400 bits/sec)
* International standard GSM 06.10 full rate speech transcoding (13,000 bits/sec)
Cryptographic Details:
* Unique session key generated for each conversation using Diffie-Hellman exponential key exchange (2048 bit modulus) (U.S. Patent No. 4,200,770 licensed by Cylink Corporation)
* Defense against "man in the middle" active attack using interleave protocol combined with voice verification of six digit key name derived from the public exponentials
* Hardware Random number generator based on Johnson noise
* Three Key Triple-DES (168 bit key), operating in modified counter mode.
To anyone who's read the PGPfone docs, this sounds very similar, PGPfone uses 3DES (as one option: also CAST, Blowfish), but it's a 2 key 3DES rather than 3 key (I think). PGPfone works with 9600/14400/28800 modems, uses Diffie Hellman key exchange, uses a commitment to exchanges by passing the hashes of the exchanges prior to traditional dh key-exchange (we'll see if this compares to what is described here as an `interleave protocol'). PGPfone offers several GSM codecs. Do you see any barrier to PGPfone being able to interoperate with your product once your specs are published? (Aside from a fast PC/MAC to keep up -- 3DES is the most computationaly expensive encryption algorithm used by PGPfone). Also I believe I read somewhere in your announce that upgrades are possible -- can these happen in software only? Flash BIOS upgrade? If it is software upgradable are you releasing the programming specs also? A very nice product, sure beats the hell out of clipper based phones, and the various snake oil offerings, Adam -- #!/bin/perl -sp0777i<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<j]dsj $/=unpack('H*',$_);$_=`echo 16dio\U$k"SK$/SM$n\EsN0p[lN*1 lK[d2%Sa2/d0$^Ixp"|dc`;s/\W//g;$_=pack('H*',/((..)*)$/)