Richard received a message from Matthew that was encrypted using a symmetric cryptosystem. What key should Richard use to decrypt the message? a. Matthew’s public key b. Matthew’s private key c....

Richard received a message from Matthew that was encrypted using a symmetric cryptosystem. What key should Richard use to decrypt the message? a. Matthew’s public key b. Matthew’s private key c. Richard’s public key d. Richard’s private key e. Shared secret key Which of the following cryptographic concepts has been widely discredited among the information security community? a. Confidentialit b. Nonrepudiation c. Security through obscurity d. Integrity e. Authentication