Advanced Encryption Standard

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What Does Advanced Encryption Standard Mean?

The Advanced Encryption Standard (AES) is a symmetric-key block cipher algorithm and U.S. government standard for secure and classified data encryption and decryption.

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In December 2001, the National Institute of Standards (NIST) approved the AES as Federal Information Processing Standards Publication (FIPS PUB) 197, which specifies application of the Rijndael algorithm to all sensitive classified data.

The Advanced Encryption Standard was originally known as Rijndael.

Techopedia Explains Advanced Encryption Standard

The AES has three fixed 128-bit block ciphers with cryptographic key sizes of 128, 192 and 256 bits. Key size is unlimited, whereas the block size maximum is 256 bits. The AES design is based on a substitution-permutation network (SPN) and does not use the Data Encryption Standard (DES) Feistel network. These days the majority of VPN providers use some form of AES.

In 1997, the NIST initiated a five-year algorithm development process to replace the DES and Triple DES. The NIST algorithm selection process facilitated open collaboration and communication and included a close review of 15 candidates. After an intense evaluation, the Rijndael design, created by two Belgian cryptographers, was the final choice.

The AES replaced the DES with new and updated features:

  • Block encryption implementation
  • 128-bit group encryption with 128, 192 and 256-bit key lengths
  • Symmetric algorithm requiring only one encryption and decryption key
  • Data security for 20-30 years
  • Worldwide access
  • No royalties
  • Easy overall implementation
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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.