CRY303c

Message authentication is a mechanism or service used to verify the integrity of a message. True False True Joseph Mauborgne proposed an improvement to the Vernam cipher that uses a random key that is as long as the message so that the key does not need to be repeated. The key is used to encrypt and decrypt a single message and then is discarded. Each new message requires a new key of the same length as the new message. This scheme is known as a(n) __________ .

An original intelligible message fed into the algorithm as input is known as _________ , while the coded message produced as output is called the __________ .

The MAC does not provide a digital signature because both sender and receiver share the same key. True False True Restoring the plaintext from the ciphertext is __________ .

A __________ attack involves trying every possible key until an intelligible translation of the ciphertext is obtained.

One means of forming a MAC is to combine a cryptographic hash function in some fashion with a secret key. True False True Techniques used for deciphering a message without any knowledge of the enciphering details is ___________ .

The ___________ takes the ciphertext and the secret key and produces the original plaintext. It is essentially the encryption algorithm run in reverse.