Am Dienstag, 9. Dezember 2014 02:29:30 UTC+1 schrieb James Kelvin: > > Thank you very much for your Threefish implementation. > > However it doesn't work as I expected . > > I have encountered a problem with key size. Regarding specification: Key > sizes are 256, 512 or 1024 bits (key size is equal to block size). > > For example - your implementation of 1024bit version refuses 128B key and > demands 144B (1152bit): > /struct Threefish1024_Info : public *FixedKeyLength<144>*, public > FixedBlockSize<128>, public FixedRounds<80>/ > > So I'm little confused - don't know maybe I have missed something. > > > -- > View this message in context: > http://crypto-users.996303.n3.nabble.com/Threefish-tp4700p5250.html > Sent from the Crypto++ Users mailing list archive at Nabble.com. >
First I want to clarify that the only work I did was to take Skein3Fish's code and adapt if for Crypto++; you might've read that I was using this code for private purposes and shared it because there was a need, so I didn't document where those extra 16 Bytes come from. You might or might not know that Threefish normally accepts 4 Parameters: Key- (and Block-)size, Key, IV (if any) and Tweak. As there's no standard in Crypto++ concerning tweakable blockciphers (to which Threefish belongs) I took the standard I found and did my best to integrate Threefish into it. The purpose of those 16 extrabytes for every single blocksize is, that they're the tweak. So you're essentially specifying (is that spelled right?) Key||Tweak (or other way around, don't remember). So the tweak is basically taken as part of the key because I think that's the best way - besides implementing a whole new concept - of integrating Threefish. BR JPM -- -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [email protected]. More information about Crypto++ and this group is available at http://www.cryptopp.com. --- You received this message because you are subscribed to the Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
