17 Dec
2003
17 Dec
'03
11:17 p.m.
Karl Lui Barrus wrote:
Hm.... I don't think you reduce the keyspace all that much. The restriction on e (and d) is they must be relatively prime to phi(n), and if n = p q = (2p' + 1) (2q' + 1) then phi(n) = 4p'q', in which case e (and d) can't be 2, 4, p', q', 2p', 2q', 4p', 4q', or 4p'q', a total of 9 numbers out of the total possible. I don't remember the
Argh, I left out p'q' and 2p'q', which brings the total to 11 unusable numbers. -- Karl L. Barrus: klbarrus@owlnet.rice.edu keyID: 5AD633 hash: D1 59 9D 48 72 E9 19 D5 3D F3 93 7E 81 B5 CC 32 "One man's mnemonic is another man's cryptography" - my compilers prof discussing file naming in public directories