eralha Posted March 9, 2009 at 12:17 PM Report Share #249358 Posted March 9, 2009 at 12:17 PM We need a encoding key(e) and a decoding key(d). We start with E, E should be coprime to (p-1*q-1) The security of RSA does not depend on E, we can check the primes against (p-1*q-1) until we find one. 3, 5, 7 etc (the security of RSA depends on how hard it is factoring the number we choose as modulus). 3 is coprime to 4265, lets choose 3 as our E. In order to calculate D we must do an inverse mod operation like so E^-1 mod (p-1*q-1). Inverse mod can be found on any good calculator and is often shown as M^-1 i am using Hexprobe Multibyte Calculator so 3^-1 mod 4265 is 2843(d) now take 3 as our encoding key(e) and 2843 as our decoding key(d). The RSA rules are now C = P^E mod m P = C^D mod m P = Plain Text C = Cipher Text 1000^E(3) mod m(4399) = C(1724) 1000 encrypts to 1724, lets decode it now. 1724^D(2843) mod m(4399) = P(1000) Boas pessoal estou a tentar perceber esta logica, o que nao entendi bem foi como gerar a chave de desencriptação, dame sempre valores esquisitos, as contas que estou a fazer são em action script, mas o meu problema está na matemática. var modulus:Number = 4399; var eKey:Number = 3; var dKey:Number = (eKey^-1)%4265; var c:Number = Math.pow(1000,eKey)%modulus; var p:Number = Math.pow(c, dKey)%modulus; trace("EKEY: "+eKey+" Cypher "+c+" DKEY: "+dKey+" Plain: "+p); OUTPUT: EKEY: 3 Cypher 1724 DKEY: -4 Plain: 1.1320118003091641e-13 Link to comment Share on other sites More sharing options...
Rui Carlos Posted March 10, 2009 at 04:52 PM Report Share #249687 Posted March 10, 2009 at 04:52 PM Provavelmente precisas de implementar tu a operação de exponenciação... É que a implementação da linguagem não deve estar a fazer exponenciação modular. Além disso, os tipos de dados do ActionScript têm precisão suficiente para suportar estas operações? Rui Carlos Gonçalves Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now