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Chapter 7 PKI and Cryptographic Applications

Written Lab

  1. Explain the process Bob should use if he wants to send a confidential message to Alice using asymmetric cryptography.

    Use Alice's public key to encrypt the message.

  2. Explain the process Alice would use to decrypt the message Bob sent in question 1.

    Use her private key to decrypt the message sent by Bob.

  3. Explain the process Bob should use to digitally sign a message to Alice.

    Bob should generate a message digest from the plaintext message using a hash function. He should then encrypt the message digest using his own private key to create the digital signature. Finally, he should append the digital signature to the message and transmit it to Alice.

  4. Explain the process Alice should use to verify the digital signature on the message from Bob in question 3.

    Alice should decrypt the digital signature in Bob's message using Bob's public key. She should then create a message digest from the plaintext message using the same hashing algorithm Bob used to create the digital signature. Finally, she should compare the two message digests. If they are identical, the signature is authentic.