Greetings,
The concept of "receipts" for email messages is one that is certainly used in
various environments with varying degrees of protection for the parties. I am
not convinced that any existing system currently implements receipt capability
with the "strongest" level of protection for both the sender and recipient.
That>strong level can be described as:
Alice wants to send message, M, to Bob. She wants to get a receipt proving
that>Bob received M from Alice. She does not want Bob to see or read M before
she is>capable of having the receipt.
Very interesting. The first part is what I call the draft notification problme.
[I might as well pretend to be British. My fingers just won't type those
characters in the right order.]
Bob wants to make sure that if he signs a receipt, that Alice will let him see
the message M.
Maybe this is the Ed McMann problem? I don't want to sign a receipt and then
not get to read the secret PIN that allows me to claim my millions of dollars
sweepstakes winnings.
This is possible and is discussed in depth in "Certified Electronic Mail" by
Professor Doug Tygar and myself presented at ISOC 94. (see www.eit.com/~ali)
I wouldn't have thought this was possible without a trusted computer system.
This must involve some secret sharing scheme, or perhaps a zero-knowledge
proof? Have you been consorting with David Chaum again?
This capability is very useful especially in electronic commerce.
I don't immediately see the applicability to electronic commerce?
Bob
Robert R. Jueneman
GTE Laboratories
1-617-466-2820 Office
1-508-264-0485 Telecommuting