Exam 3: Public-Key Cryptography and Message Authentication

The two most widely used public key algorithms are RSA and _________ .

The key exchange protocol is vulnerable to a man-in-the-middle attack because it does not authenticate the participants.

The security of the Diffie-Hellman key exchange lies in the fact that, while it is relatively easy to calculate exponentials modulo a prime, it is very easy to calculate discrete logarithms.

The __________ approach has two advantages: it provides a digital signature as well as message authentication and it does not require the distribution of keys to communicating parties.

In addition to providing authentication, a message digest also provides data integrity and performs the same function as a frame check sequence.

The key algorithmic ingredients of __________ are the AES encryption algorithm, the CTR mode of operation, and the CMAC authentication algorithm.

Using an algorithm that is designed to provide only the digital signature function, the _________ makes use of the SHA-1 and cannot be used for encryption or key exchange.

The __________ algorithm accepts the ciphertext and the matching key and produces the original plaintext.

The __________ property is the "one-way" property and is important if the authentication technique involves the use of a secret value.

The _________ was developed by NIST and published as a federal information processing standard in 1993.

The strength of a hash function against brute-force attacks depends solely on the length of the hash code produced by the algorithm.

Like the MAC, a __________ accepts a variable size message M as input and produces a fixed size message digest H(M) as output.Unlike the MAC, it does not take a secret key as input.

The two important aspects of encryption are to verify that the contents of the message have not been altered and that the source is authentic.

Message encryption alone provides a secure form of authentication.

Because of the mathematical properties of the message authentication code function it is less vulnerable to being broken than encryption.

A _________ is when two sides cooperate to exchange a session key.

The main advantage of HMAC over other proposed hash based schemes is that HMAC can be proven secure, provided that the embedded hash function has some reasonable cryptographic strengths.

The __________ property guarantees that it is impossible to find an alternative message with the same hash value as a given message, thus preventing forgery when an encrypted hash code is used.

__________ is a term used to describe encryption systems that simultaneously protect confidentiality and authenticity (integrity) of communications.

Cryptographic hash functions generally execute slower in software than conventional encryption algorithms such as DES.