Encryption & Prime Numbers

[Mark Brownell]

On Monday, September 6, 2004, at 06:06 PM, Alex Tweedly wrote:
>
> Don't know about Blowfish specifically; it's a private-key algorithm, 
> so may have no requirement on primes.

It has none. It uses a symmetric key encryption process.

> In general public/private key systems depend on the inability to 
> decompose very large numbers into their prime factors. So to generate 
> a suitable private key, you generate a number of primes, and multiply 
> them together; if someone could easily decompose that, they would be a 
> large part of the way towards discovering your private key.

Interesting. After checking out the AES algorithm the variable length 
key and variable block size look like they were designed to work well 
with RSA.  If this weakness has been discovered by a mathematician  
then they will need to come up with a suitable private key system. 
There appears to be no tricks out there to clobber AES or Blowfish 
other than a brute force attack.

Thanks for the info on RSA,

Mark