17 Dec
2003
17 Dec
'03
11:17 p.m.
Mark M. <markm@voicenet.com> writes:
The normal key-length recommendation was 96 bits. 64 bits and 80 bits are equivalent to 512 bits and 768 bits respectively. I would guess that a 1024-bit key is about as strong as an 96-bit key. The first two numbers are from _Applied Cryptography_; my estimate is an extrapolation from the data = in AC.
These number should be qualified with the date on which the estimate was determined. New factoring techniques increase the number of RSA key bits required to make factoring work equivalent to a given brute-force search. Also, I would think that the NFS makes 512 bit RSA key factoring easier than brute-forcing 64-bits of key space... andrew