Which of the following symmetric key algorithms are examples of block ciphers? (Select THREE).
A. RC4 B. 3DES C. AES D. MD5 E. PGP F. Blowfish
Answer: B,C,F
Explanation: B: Triple DES (3DES) is the common name for the Triple Data Encryption Algorithm (TDEA or Triple DEA) symmetric-key block cipher, which applies the Data Encryption Standard (DES) cipher algorithm three times to each data block.
C: Advanced Encryption Standard (AES) is a block cipher that has replaced DES as the current standard, and it uses the Rijndael algorithm. It was developed by Joan Daemen and Vincent Rijmen. AES is the current product used by U.S. governmental agencies.
F: Blowfish is an encryption system invented by a team led by Bruce Schneier that performs a 64bit block cipher at very fast speeds.