a free cross platform checksum utility, supports 58+ hash algorithms
...Jacksum 1.7.0 is a platform independent checksum utility (written entirely in Java) for computing and verifying (integrity check) checksums, CRC and hashes (fingerprints). It supports 58 popular hash algorithms and a lot of unique features.
OpenChord is an open source implementation of the Chord distributed hash table as described in the paper by Ion Stoica et al. "Chord: A scalable peer-to-peer lookup service for internet applications". It is available under GNU GPL.