1. Nov 9, 2004

### Zurtex

I'm working on encrypting a small message using RSA. Are there any types of primes or primes of particular property that would make RSA decryption particularly difficult?

Furthermore are there any better ways that just randomly trying to factorise to break RSA encryption or is there some particularly good way?

2. Nov 9, 2004

### TenaliRaman

Check here,
http://www.rsasecurity.com/rsalabs/node.asp?id=2213

RSA is getting weaker by the day. There are algos like Elliptic Curve Factorisation and pollards rho techniques (this is getting modified by the day to give more and improved pollard rho techniques .... ). Impressive isn't it ?? once the most hardest encryption system is losing ground .... (People are now reverting to Diffie Hellman and El-Gamal these days .... as u can see from the PGP system)

Check here for,
Elliptic Curve Factorisation :
http://www.alpertron.com.ar/ECM.HTM
(brilliant java piece)

Check here for,
Pollard Rho techniques :
http://mathworld.wolfram.com/PollardRhoFactorizationMethod.html
http://planetmath.org/encyclopedia/PollardsRhoMethod.html

-- AI

3. Nov 9, 2004

### Zurtex

Wow! Thanks, I don't have to worry too much as I am a Freshmen who is far more in to maths than any of my fellow class mates, so with a bit of luck the only algorthm they'll use to test for primes is the very traditional brute force.

The program is very impressive, it can factorise quicker than matlab can multiply the factors.

I’m still a little unsure about RSA though, will I be factorising pq or (p-1)(q-1)? Still grappling with the understanding the theory a bit (mind you I’m reading several weeks ahead of the lectures so no big deal yet).

Edit: Dosn't really matter, I'll read it all up. Thanks again

Last edited: Nov 10, 2004
4. Nov 13, 2004

### antevante

If you want to decode it without knowing the keys you will factorise pq since it is public (p-1)(q-1) is not public.
I'm in the Ib diploma program and I'm thinking of writing an extended essey about RSA. Do you have any tips?
/Andreas