>>>>> "Malcolm" == Malcolm Howell <hashcash@xxxxxxxxxxxxxxxxxxx> writes: [...] Malcolm> Also, if you're concerned about the leading zeros which are Malcolm> guaranteed to be in the SHA-1 hash of a valid stamp, you could Malcolm> hash the stamp without including the counter. Yes, or add a salt (e.g. add an extra '0' or other known character at the beginning, or some other similar perturbation). It shouldn't be too hard to work around, as long as you always do it in a consistent way. -- Hubert Chan <hubert@xxxxxxxxx> - http://www.uhoreg.ca/ PGP/GnuPG key: 1024D/124B61FA Fingerprint: 96C5 012F 5F74 A5F7 1FF7 5291 AF29 C719 124B 61FA Key available at wwwkeys.pgp.net. Encrypted e-mail preferred.