Question

One of the oldest of the modern symmetric ciphers is________. It was a block cipher developed by IBM in the early 1970s and used as a U.S. government standard until the 1990s. IBM had originally developed a cipher called Lucifer, which was designed by Horst Feistel. When the U.S. government began seeking a standardized encryption algorithm, IBM worked with the National Security Agency (NSA) to alter Lucifer to fit the government's needs, thus it was created. As you may guess, it is a Feistel cipher. A) DES (Data Encryption Standard)

B) AES (Advanced Encryption Standard)

C) RSA (Rivest–Shamir–Adleman)

D) Blowfish

Answer 1

The oldest of the modern symmetric ciphers mentioned is DES (Data Encryption Standard), developed by IBM and modified in collaboration with the NSA to become the U.S. government encryption standard from the 1970s until the 1990s.

Step-by-step explanation:

One of the oldest of the modern symmetric ciphers is DES (Data Encryption Standard). Developed by IBM in the early 1970s, DES was a block cipher that became a U.S. government standard for encryption until it was succeeded by the Advanced Encryption Standard (AES) in the late 1990s. As a Feistel cipher, DES employs a technique where the plaintext is iteratively run through several rounds of permutation and substitution, which comprise the Feistel structure. IBM's initial cipher, called Lucifer, was the precursor to DES and was altered in collaboration with the NSA to meet the U.S. government's specifications for encryption.