Discuss how the asymmetric encryption algorithm can be used to achieve the following goals:
a) Authentication: the receiver knows that only the sender could have generated the message.
b) Secrecy: only the receiver can decrypt the message.
c) Authentication and secrecy: only the receiver can decrypt the message, and the receiver knows that only the sender could have generated the message.
Assymetric encryption can be done through PKI (Public Key Infrastructure). An application PKI encryption is that of digital signature schemes. Digital signature schemes can be used for sender authentication and non-repudiation. A user who wants to send a message creates a digital signature for this message, and then sends this digital signature (together with the message) to the intended receiver. Digital signature schemes have the property that signatures can be computed only with the knowledge of the correct private key. To verify that a message has been signed by a user and has not been modified, the receiver needs to only know the corresponding public key. ...