US 2004/0165727 A1 · SYSTEM FOR ON-LINE AND OFF-LINE DECRYPTION

Abstract

A secure communication system wherein message decryption may be performed while off-line, or optionally while on-line. A sender encrypts a message based on the message key and sends it to the recipient. An envelope containing a message key is created by encrypting the message key based on a verifier, where the verifier is based on a secret of the recipient. The recipient is provided the envelope, along with the message or separately, from the sender or from another party, contemporaneous with receipt of the message or otherwise. The recipient can then open the envelope while off-line, based on their secret, and retrieve the message key from the envelope to decrypt the message. In the event the recipient cannot open the envelope, optional on-line access permits obtaining assistance that may include obtaining an alternate envelope that the recipient can open.

Claims56

Dependent claims

A method for secure communication of a message from a sender to a recipient, the method comprising the steps of:

creating an envelope containing a message key by encrypting said message key based on a verifier that is based on a secret of the recipient;
providing said message key to the sender;
at the sender, encrypting the message based on said message key;
sending the message from the sender to the recipient;
providing said envelope to the recipient;
and
at the recipient:
opening the envelope based on said secret of the recipient;
retrieving said message key from the envelope;
and
decrypting the message based on said message key.

8 more elements

Dependencies are inferred from the claim text.

System for on-line and off-line decryption

Life of this patent

System for on-line and off-line decryption

Life of this patent

Abstract

Claims56