[*] This material is based on work supported by the National Science Foundation under cooperative agreement IRI-9411299. Additional support for Camp and Tygar was received from ARPA contract F33615-93-1-1330, a contract from the US Postal Service, and an equipment grant from IBM. This work is the opinion of the authors and does not necessarily reflect the opinion of any funding sponsors or the US Government.

[1]A recent working paper from the Cross-Industry Working Team for the National Information Infrastructure has produced a similar list of properties which they list under the following headings: stability of monetary value, exchangeability, retrievably, tamper-resistance. They also list as desirable properties of transactions: non-refutable, accessible, reliable, private, protected. See http://cnri.reston.va.us:3000/XIWT/public.html

[2]For example, law enforcement access to information is conditional upon the ability to obtain a warrant.

[3]This is a constraint on government receipt of information, not bank disclosure. Fourth Amendment protection applies to personal records held by banks.

[4]Law enforcement may have access to full information about a purchase if the merchant keeps records.

[5]If a payor's bank does not report to the payee's bank that the payor has insufficient funds in a timely manner the payor's bank becomes responsible for making good the check.