Lightweight Micro-cash for the Internet

Abstrac t . We propose a micro-cash technique based on a one-time signature scheme: signing a message more than once leads to disclosure of the signer's private key. In addition to usual cash properties such as off-fine bank for payment and spender's anonymity, the technique also provides a number of useful features. These include: identifying double spender with strong proof, cash revocable for identified double spender, independent of using tamper-resistant devices, coin sub-divisible to smaller denominations, and system simplicity in terms of small-sized data for cash representation as well as simple protocols for cash withdrawal, payment and deposit. We reason that these features support a lightweight cash system suitable for handling very low value payment transactions, such as information purchases on the Internet.