The code is placed under public domain by Kazuho Oku <kazuhooku@gmail.com>.

The MD5 implementation is based on a public domain implementation written by
Solar Designer <solar@openwall.com> in 2001, which is used by Dovecot.

The SHA1 implementation is based on a public domain implementation written
by Wei Dai and other contributors for libcrypt, used also in liboauth.

The SHA224/SHA256 implementation is based on a public domain implementation
by Sam Hocevar <sam@hocevar.net> for LibTomCrypt.