Exec summary: - We chose to compute twice as many tables that are half as high. The computational effort does not change much but the coverage will be better (at the cost of increased attack time).
- Once a table reaches 4,320 MB it is done and you should start the next table with new parameters. - If you are still using the old round function (table generation started before Oct 25th) you should start a new table regardless of the current size. On Nov 23, 2009, at 2:29 PM, sascha wrote: > Dear list, > > after analyzing test data, we had to update our calculations on the > table > parameters. > Right now, after 270 million chains have been generated, for every > new unique chains produced, one merging chain is also produced. > It makes sense to stop at this point where the ratio is 50/50. > The new policy is to generate 270 million chains per table, which > will contain 190 million unique chains (=2^27.5). > Because of that 2^9.5 instead of 2^8.5 table must be generated and > the lookup complexity also doubles. > This table parameter is the recommended value. The effect of producing > a table with more chains is that it takes longer to generate it not > only because more chains are needed, but also because the ratio of > chains to merges is lower. The advantage of having a table with 2^28.5 > unique chains is that it takes half the time to do a lookup with it > than with two tables of size 2^27.5 > So in a sense we are trading lookup complexity for generation > complexity > here. The lookup performance can also be improved later when all > tables > are generated by appending new chains to the existing tables. > This will be an option if there is a need to perfect the tables and > can > be decided then. > Instructions on the handling of finished tables will be posted when > time permits. Until then you can just let the data lay around. > > _______________________________________________ > A51 mailing list > [email protected] > http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51 _______________________________________________ A51 mailing list [email protected] http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
