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| Authored by: bugstomper on Tuesday, January 29 2013 @ 04:41 PM EST |
@Anonymous: Sorry about the extra 12 zeroes typo. I copy and pasted, multiplied
the 128 by 32, then swiped and deleted 9 zeroes. Unfortunately I copied the
wrong line, the one before dividing by a trillion.
But I agree with your point that the moral question is not answered by looking
only at the technology. I was just pointing out to RAS that the technology
really does mean that it is not possible to crack a 128 bit random key through
strictly brute force. So you cannot bring in ease of cracking it compared to 10
years ago as one of your arguments whatever side you are arguing for.
@RAS: That link is about cracking a 932 bit RSA key, which is not the same
problem as brute-forcing a 128-bit random key of a symmetric cipher like AES.
Cracking an 932-bit RSA key is a problem in calculating the two prime factors of
a 932 bit number. 128 bit keys refer to ciphers like AES where the key is just a
random number that has to be found by trying every possibility, not by
performing a hard calculation such as factoring large numbers.
According to the wikipedia article http://en.wikipedia.org/wiki/Key_size as of
2003 the company RSA Security estimated that 1024-bit RSA keys are equivalent in
strength to 80-bit symmetric keys, 2048-bit RSA keys to 112-bit symmetric keys
and 3072-bit RSA keys to 128-bit symmetric keys. In other words, the best known
algorithms for factoring large prime numbers can be used to crack a 3072 bit RSA
key in roughly the amount of time it would take to brute-force crack a 128-bit
symmetric key.
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