Which of the following algorithms is found to be suitable for both digital signature and encryption?
A.
SHA-1
B.
MD5
C.
AES
D.
RSA
Explanation:
RSA (which stands for Rivest, Shamir, and Adleman) is an algorithm for public-key
cryptography. It is the first algorithm known to be suitable
for signing as well as encryption, and one of the first great advances in public key cryptography. RSA
is widely used in electronic commerce
protocols, and is believed to be secure given sufficiently long keys and the use of up-to-date
implementations.
Answer option B is incorrect. Message Digest 5 (MD5) is a cryptographic hash function designed by
Ron Rivest. As an Internet standard (RFC
1321), MD5 has been employed in a wide variety of security applications, and is also commonly used
to check the integrity of files.
Answer option A is incorrect. SHA-1 produces a 160-bit digest from a message with a maximum
length of (264 – 1) bits. SHA-1 is based on
principles similar to those used by Ronald L. Rivest of MIT in the design of the MD4 and MD5
message digest algorithms, but has a more
conservative design.
Answer option C is incorrect. The Advanced Encryption Standard (AES) is an encryption standard
adopted by the U.S. government. The
standard comprises three block ciphers, AES-128, AES-192, and AES-256. Each AES cipher has a 128-
bit block size, with key sizes of 128, 192,
and 256 bits, respectively. The AES ciphers have been analyzed extensively and are now used
worldwide, as was the case with its
predecessor, the Data Encryption Standard (DES).