-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/04/2010 12:09 PM, Scott McMurray wrote:
I wrote up some SHA message hashers recently, which came out rather nicely using templates to handle the commonalities between SHA-1/256/384/512.
I realize I'm still new here, but having written a large library of hashing functions myself several years ago (purely for fun, never used... I was thinking of proposing it for Boost inclusion after XInt), I feel that I have a little experience to contribute.
The one issue that came up is how to handle retrieving the hash from the accumulator. [...]
Here are a couple of options:
1) The hash() function is non-const, and it appends the passing and length, calculates the hash, and resets the accumulator to be ready for the next message. This is perhaps the most efficient interface. [...]
I think I like (1) best, because it allows the user to copy it and get (2) if they'd rather, and doesn't have the potential call sequencing problem of (3).
Any opinions, suggestions, alternatives, or comments?
I agree with your opinion, with a slight variation: don't reset the accumulator until the user explicitly requests it. It seems counterintuitive, though I'm sure it could be made obvious with the proper function naming.
P.S. Yes, the point here is to create Boost.MD and Boost.SHA libraries. [...]
Is there a particular reason to separate the two (conceptually)? A Boost.CryptographicHash library, covering those and several other commonly used ones, seems more appealing. They would, of course, still be *logically* separate, they'd just be under the same umbrella name, and share the same interface. I'll contribute code for several more formats (MD2, RIPEMD 128/160/256/320, Tiger 128/160/192, Tiger2 128/160/192, and Whirlpool, all byte-oriented only), if you're interested. They probably need some work (they were written several years ago), but the core code is sound. I'm pretty sure none of them are patent-encumbered, but of course I'd make certain. - -- Chad Nelson Oak Circle Software, Inc. * * * -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAku58wkACgkQp9x9jeZ9/wT/BACcCF6oLl4NdoDfIGYT3//V9bof 5egAoJPJaZxIGBggCJlioBYLEdQeJF+R =7am8 -----END PGP SIGNATURE-----