Common use of Key Agreement Clause in Contracts

Key Agreement. The agreement of symmetric key is accomplished by public key system. As shown in Figure 4, ▇▇▇▇▇ encodes her public key kp into acoustic signal and transmits the signal to Bob. The encoded acoustic signal from ▇▇▇▇▇ should preserve the channel ACR features. Bob decodes ▇▇▇▇▇’s public key after verified whether it is from ▇▇▇▇▇ using ACR features. The message coding should be efficient and be able to tolerate errors in the channel. Then, Bob generates a session key ks and encrypts it using ▇▇▇▇▇’s public key kp. Assume the encrypted session key is Ekp (ks), Bob encodes Ekp (ks) into acoustic signal and transmits the signal to ▇▇▇▇▇. ▇▇▇▇▇ verifies the signal source is from Bob. Then she decodes Ekp (ks) and uses her private key to obtain ks. Then the session key ks can be used by ▇▇▇▇▇ and ▇▇▇ for further communication. In this progress, the attackers have no opportunity for spoofing due to the identity verification by ACR, and the public key system prevents attackers from deriving the session key ks.