 |
 NWT Coach Cardinal Outline Signature Compact Umbrella $67.99 Time Remaining: 2d 6m Buy It Now for only: $67.99 |
Outline Signature
Open Transactions (Metafilter)
Open Transactions is an anonymous digital cash system based upon the Lucre
anonymized cache cryptographic library.
Anonymous digital cash system involve a _mint_ who blind signs a coin for the
purchasing user. Afaik, all blind signing protocols are implemented using a
multiplicatively homomorphic public-key crypto-system such as unpadded RSA
(previously). In principle, the mint cannot conspire with venders to correlate
a users transactions without using side channel information, like usernames,
IP addresses, etc. (example)
In outline, the user hashes and encrypts a well chosen serial number x to
obtain x', the mint then signs x' to obtain y', and the user decrypts y' using
their private-key to obtain a signature y for x, the coin is the pair (x,y).
Anyone may use the mint's public key to verify that (x,y) is indeed a coin
signed by the mint. The mint prevent double spending/redemption by ensuring
that each serial number x only gets used once. A priori, the need for users to
choose x means the mint must rotate private keys and/or limit a coin duration.
Lucre itself is designed to avoid the digital cash patents held by David
Chaum, which perhaps retarded the development of digital ...
Best Quality Coach Signature Outline Op Art Maggie Shoulder Bag Purse 16153 Khaki