Adam Back wrote:
i know. i was mentioning the 2 cases where one has to calculate both blocks, and that these don't happen for every attempt.I think the issue is that SHA1 is chained thru the 5x 32-bit (160-bit) chaining/state variables A,B,C,D,E. So in the 2nd case you have to recompute the 2nd block even though the 2nd data doesn't change.
(It would be nice to find a way to remove the -Z options, we tried before, and failed so far).
Adam
On Wed, Dec 07, 2005 at 11:19:11PM +0100, bas wrote:
[...]
changes which would require calculation of both blocks are
1: the string becoming longer (because the counter becomes longer), so it becomes 2 blocks
2: a char of the counter, other than the least significant, changes, which is in the first block.
what does the padding refer to? what am i missing?
i think if its possible at all to optimize -Z2 so it's like 1.1 slowdown, and not 2x, this is a good idea and it should become the default, and the existing -Z1 setting becomes obsolete.
