Below is a list of potentially desirable properties for an internet payment system.
- Security: The digital cash cannot be copied and reused.
- Independence: The security of the digital cash is not dependent on any physical location. The cash can be transferred through computer networks.
- Unlinkable: Separate transactions by the same user cannot be linked together.
- Anonymous: The user cannot be linked to any of her transactions.
- Off-line: When a user pays a merchant, the transaction can complete without either of them communicating with a third party.
- Equality: Users and merchants are equal and interchangeable. That is, any user can behave as a merchant and accept payments.
- Divisibility: A piece of digital cash in a given amount can be subdivided into smaller pieces of cash in smaller amounts. (Of course, everything has to total up properly in the end.)
- Integer: The amount of money transferred in a payment is represented as an integer multiple of some smallest possible denomination. For example, every payment in US cash must be an integer multiple of 1 cent.
- Cryptographic: The transaction protocols rely on cryptography and heavy computation.
- Plaintext: The transaction protocols do not rely on cryptography or any computation.
References:
AppliedCryptography: p. 146