43 | | 9. The estimates given here are in terms of work factor, i.e. they are products of machine size and attack time. See [http://cr.yp.to/snuffle/bruteforce-20050425.pdf this paper by Dan Bernstein] for discussion of parallel brute-force attacks, including attacks against multiple keys at once. Note that the applicability of these multiple-key attacks depends on the encryption mode. CTR mode with a fixed IV would be particularly vulnerable, so I (David-Sarah) think we should use a variable IV. (Bernstein prefers simply to make the key longer, which would be good advice for most protocols, but most protocols don't have the usability constraint of the key length contributing to URL length.) |
| 43 | 9. The estimates given here are in terms of work factor, i.e. they are products of machine size and attack time. See [http://cr.yp.to/snuffle/bruteforce-20050425.pdf this paper by Dan Bernstein] for discussion of parallel brute-force attacks, including attacks against multiple keys at once. Note that the applicability of these multiple-key attacks depends on the encryption mode. CTR mode with a fixed IV would be particularly vulnerable, so I (Daira) think we should use a variable IV. (Bernstein prefers simply to make the key longer, which would be good advice for most protocols, but most protocols don't have the usability constraint of the key length contributing to URL length.) |