... protocol run(c) off-lineon-line[optional][optional]AAAin-lineTTPTTPTTPoff-lineFigure 13.2:In-line, on-line, and off-line third parties.In-line third parties are of particular interest ... properties of escrow systems include:1. applicability to store-and-forward vs. real-time user communications2. capability of real-time decryption of user traffic3. requirement of tamper-resistant ... be an on-line third party, but the certificationauthority is not.13.4 Remark (pros and cons: in-line, on-line,off-line) Protocols with off-linethird parties usu-ally involve fewer real-time message...