>>>>> "Justin" == Justin Guyett <justin-hashcash@xxxxxxxx> writes: [...] Justin> What's the point of including the bitcount? That seems like a Justin> completely inconsequential piece of information. It could be a Justin> lie, or a spammer could set it to the actual number of bits. Since the bitcount is part of the token, you can't change the bitcount without messing up the hash. (i.e. the leading bits won't be 0 any more.) Justin> Why give end users the opportunity to create draconian mail Justin> filtering rules? If I send a stamp with a claimed value of 26 Justin> bits but there are only 24, and the recipient requires 22, what Justin> are they going to do? It's my fault for lying, but is the Justin> hashcash header supposed to weed out compulsive liars or merely Justin> test for proof of work? It is to ensure that, if you require 22, and the sender creates a 20 bit stamp, but gets lucky and gets a 22 bit stamp, the stamp will be treated as only 20 bits. (There is a 50% chance that a generated stamp will be longer than the length attempted.) There is no reason anyone would try to claim that the stamp is longer than it really is. Justin> This example is v0 with an advisory reverse-postage and sender Justin> address/hostname added: Justin> X:date:recip_resource:sender_postage:sender_resource:random Justin> X:20040531062557:hashcash@xxxxxxxxxxxxx:25:sender@xxxxxxxxxxxxxx:asdlkfj1325ASDFJ Justin> Is that really so lacking due to exclusion of an options field, Justin> hash value/multi-puzzle indicator, and counter? The 25 is Justin> advisory only, and indicates the reverse-postage to the sender. Justin> It's mentioned on the camram page. Why is it not in hashcash v1 Justin> stamps? You can add it using the extensions field. I assume it's not in v1 because it's not required for proper operation of hashcash, and is optional. -- 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.