the wiretap chip clones and secure key exchange u uicvm uic edu writes the cryptographic algorythm must be kept secret or private individuals could make clipperclones with which they could transmit messages which the feds would not have ready access to not necessarily i ve been thinking about this and if this chip scheme is to provide any real security there must be some sort of key exchange either using a public key encryption scheme or using a key exchange scheme like diffie hellman if there s an out of band transmission of a shared session key then what protects that band from eavesdropping if the phone company or some other online central authority generates a session key and sends it to both users then what s the point of going to the trouble of having some complicated key depositories just ask the phone company for a copy of the session key for each call now it s probably not practical for each user to keep an online copy of every public key used by anyone anywhere right so probably there will be some way of getting these keys verified this might be a digitally signed by the chip manufacturer copy of the public key in this unit stored by this unit it might also be an online directory with access to everyone s public keys this would introduce another weakness to the security of the scheme of course presumably if you don t use your designated key you can t get a verified connection to other standard chips it might be useful to have a modified chip which would allow you to use either the original public private key pair or some other key pair and verification scheme unfortunately this would not allow you to call most people and establish secure communications john kelsey i hope somebody starts doing this soon after the first ones are released
