artbj
Newbie
Posts: 1


« on: April 01, 2006, 02:25:48 PM » 

factoring large numbers is hard. However, with the advances in number theory and computing power, it is getting easier. In 1977 Ron Rivest said that factoring a 125digit number would take 40 quadrillion years. In 1994 RSA129 was factored using about 5000 MIPSyears of effort from idle CPU cycles on computers across the Internet for eight months. In 1995 the Blacknet key (116 digits) was factored using about 400 MIPSyears of effort (1 MIPSyear is a 1,000,000 instruction per second computer running for one year) from several dozen workstations and a MasPar for about three months. Given current trends the keysize that can be factored will only increase as time goes on. The table below estimates the effort required to factor some common PGPbased RSA publickey modulous lengths using the General Number Field Sieve:
KeySize MIPSyears required to factor  512 30,000 768 200,000,000 1024 300,000,000,000 2048 300,000,000,000,000,000,000
