Openwall

You're allowed to do whatever you like with this software (including
re-distribution in source and/or binary form, with or without
modification), provided that credit is given where it is due and any
modified versions are marked as such.  There's absolutely no warranty.

[Note that you don't have to re-distribute this software under these
same relaxed terms.  In particular, you're free to place modified
versions under (L)GPL, thus disallowing further re-distribution in
binary-only form.]