Common use of Send Clause in Contracts

Send. Upon receiving (send, sid, Pi, Pj, m) where m ∈ {0, 1}A, send (sent, sid) to Pi and (receipt, sid, m) to Pj and ▇. In this setting, we are interested in key agreement protocols with an additional property that we call emulatability. A key agreement protocol π is emulatable if, 1 In the remainder of this section, we interchangeably call the parties Alice, Bob, ▇▇▇ or respectively P1, P2, A. in addition to implementing the key agreement functionality as it should, the role of Bob can be simulated by some entity E , the emulator, that learns no information about the messages transmitted through C, other than their lengths, and neither ▇▇▇▇▇ nor ▇▇▇ can distinguish whether ▇▇▇▇▇ is interacting with Bob or with E . We formalize this below. We first define a functionality DC that models a dummy channel whose task is to erase every information sent through the channel FC except for the length of the messages. Functionality FDC (Dummy channel) FDC runs with message size A and parties P1, P2 as follows: Send: Upon receiving (send, sid, m) from P1 where m ∈ {0, 1}A: If no such command has already been sent, send (sent, sid, |1|A) to P2. Otherwise, ignore the command.

Send. Upon receiving (send, sid, Pi, Pj, m) where m ∈ {0, 1}A, send (sent, sid) to Pi and (receipt, sid, m) to Pj and ▇. In this setting, we are interested in key agreement protocols with an additional property that we call emulatability. A key agreement protocol π is emulatable if, 1 In the remainder of this section, we interchangeably call the parties Alice, Bob, ▇▇▇ or respectively P1, P2, A. in addition to implementing the key agreement functionality as it should, the role of Bob can be simulated by some entity E , the emulator, that learns no information about the messages transmitted through C, other than their lengths, and neither ▇▇▇▇▇ nor ▇▇▇ can distinguish whether ▇▇▇▇▇ is interacting with Bob or with E . We formalize this below. We first define a functionality DC that models a dummy channel whose task is to erase every information sent through the channel FC except for the length of the messages. Functionality FDC (Dummy channel) FDC runs with message size A l and parties P1, P2 as follows: Send: Upon receiving (send, sid, m) from P1 where m ∈ {0, 1}A: If no such command has already been sent, send (sent, sid, |1|A) to P2. Otherwise, ignore the command.