Abstract: A communication network (10) includes any number of interconnected nodes (20), including a sending node (22), a sending gateway (24), a receiving gateway (26), and a destination node (28). A low capacity or expensive communication channel (30) resides between the sending and receiving gateways (24, 26). An original digitally signed message is sent from the sending node (22) toward the destination node (28). When the original message arrives at the sending gateway (24), the original signature is verified. If verified, the sending gateway (24) shrinks the original message into a reduced message and re-signs the message with a gateway digital signature before sending the message onward through the communication channel (30) toward the destination node (28). The destination node (28) verifies the gateway digital signature against the reduced message and is not required to de-compress the reduced message into a precise duplicate of the original message.

Abstract: A key management system includes a hierarchy (10) of independent key arbitration centers (KAC) for providing access to a user's session keys through key management centers (KMC). When a court order is issued for a user's session keys, a message requesting the keys is transferred down through hierarchy until a terminal KAC (16,36) is reached. Each KAC in the hierarchy adds its ID and signs (116) the message, verifying prior signatures (114). The user's ID is encrypted with the terminal KAC's public key. The terminal KAC engages in a blind key access procedure (129) with the KMC (18,38) to receive the user's session key. The key is provided encrypted with the requesting party's or agency's public key. Accordingly, privacy is assured because only the KMC and the requesting agency have access to the actual key value, and only the terminal KAC and requesting agency have access to the user's ID.