Stephen Sprunk wrote: > Thus spake "Richard Levitte - VMS Whacker" <[EMAIL PROTECTED]> > >>lee_dilkie> (the other thing to remember is that CTR can be used with >>lee_dilkie> any block cipher, it's not limited to AES) >> >>Absolutely. However, since it's currently very obviously an >>experimental field, and it was originally requested for AES, that's >>where we currently have it. Of course, if we had general mode >>implementation instead of having them implemented with each algorithm, >>things would be easier. Unfortunately, we get bit by performance hits >>if we do that (I think it was Steve who said he'd experimented with >>things like that some time ago). > > > I tested a bunch of different mode implementations, yes. Since some > libcrypto ciphers implement the round function directly inside the mode > loops (e.g. IDEA), there is no way to generalize modes and maintain > performance. Others, such as AES, issue a function call and could be > generalized, but the extra cost of calling a function pointer (vs a real > function) is enough to outweigh the code savings.
This is why most of the ciphers don't have generalised modes, of course! Cheers, Ben. -- http://www.apache-ssl.org/ben.html http://www.thebunker.net/ "There is no limit to what a man can do or how far he can go if he doesn't mind who gets the credit." - Robert Woodruff ______________________________________________________________________ OpenSSL Project http://www.openssl.org Development Mailing List [EMAIL PROTECTED] Automated List Manager [EMAIL PROTECTED]
