Data Security Mechanisms and their Respective Algorithms

The Advanced Encryption Standard (AES) is the newest symmetric-key encryption standard adopted by the U.S. government. The standard comprises three block ciphers, AES-128, AES-192 and AES-256, adopted from a larger collection originally published as Rijndael. Each of these ciphers 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).

AES was announced by National Institute of Standards and Technology (NIST) as U.S. FIPS PUB 197 (FIPS 197) on November 26, 2001 after a 5-year standardization process in which fifteen competing designs were presented and evaluated before Rijndael was selected as the most suitable. It became effective as a Federal government standard on May 26, 2002 after approval by the Secretary of Commerce. It is available in many different encryption packages. AES is the first publicly accessible and open cipher approved by the NSA for top secret information.

 If different keys are used for encryption and decryption, the algorithm is called an asymmetric algorithm. The most well-known asymmetric algorithm is RSA, named after its three inventors (Rivest, Shamir, and Adleman). This algorithm uses two keys, called the private key. These keys are mathematically linked. Here is a diagram that illustrates an asymmetric algorithm. Asymmetric algorithms involve extremely complex mathematics typically involving the factoring of large prime numbers. Asymmetric algorithms are typically stronger than a short key length symmetric algorithm. But because of their complexity they are used in signing a message or a certificate. They not ordinarily used for data transmission encryption.