News for hackers. Stuff that matters.

A comment on RSA-210 factored.

Re:RSA-210 factored by mrcactu5 on Monday October 07, 2013 @08:36AM (#6507758)
how did they know it was the product of two primes in the 1st place?
[ Parent | on HN ]
Re:RSA-210 factored by tgb on Monday October 07, 2013 @08:53AM (#6507854)
It's a competition set up with prizes for factoring some 'semiprimes' (numbers with exactly two prime divisors). So unless the challenge organizers had messed up, they were guaranteed this.

[1] https://en.wikipedia.org/wiki/RSA_Factoring_Challenge

[ Parent | on HN ]
Re:RSA-210 factored by bjornorn on Monday October 07, 2013 @09:22AM (#6508023)
Checking if a number is a prime or not is much easier than actually factoring it (if it is not a prime).

http://en.wikipedia.org/wiki/Primality_test

[ Parent | on HN ]