AES (Advanced Encryption Standard)
The Advanced Encryption Standard, commonly known as AES, is a symmetric encryption algorithm selected by the National Institute of Standards and Technology (NIST) in 2001 after a five-year competition to find a replacement for the aging Data Encryption Standard (DES). Here are some key points about AES:
History
- The development of AES was initiated in 1997 when NIST announced the need for a new encryption standard due to vulnerabilities in DES.
- In 1998, NIST received proposals from various organizations and individuals, including Rijndael, the algorithm that eventually became AES.
- After a series of evaluations, Rijndael, designed by Joan Daemen and Vincent Rijmen, was selected as the winner in October 2000.
- AES was officially published as FIPS PUB 197 on November 26, 2001.
Features of AES
- Symmetric Encryption: AES uses the same key for both encryption and decryption.
- Block Cipher: It operates on a fixed block size of 128 bits, with key sizes of 128, 192, or 256 bits.
- Rounds: The number of transformation rounds depends on the key size:
- 10 rounds for 128-bit keys
- 12 rounds for 192-bit keys
- 14 rounds for 256-bit keys
- Operations: Each round consists of several steps including SubBytes, ShiftRows, MixColumns, and AddRoundKey.
Security
- AES has been subject to extensive cryptanalysis, with no practical attacks found to date that can break AES with full rounds when used with appropriate key sizes.
- It is considered secure against both known plaintext and chosen plaintext attacks when properly implemented.
- The security level of AES is considered to be equivalent to its key size; for example, AES-128 is believed to offer 128-bit security.
Applications
- AES is used in various security protocols like TLS, IPsec, and Wi-Fi Protected Access (WPA).
- It's widely implemented in software and hardware, including smart cards, ATMs, and secure communications systems.
- AES is also part of many encryption products and services, including file encryption software, disk encryption, and secure messaging apps.
Standards and Certification
- AES is part of numerous international standards, including ISO/IEC 18033-3.
- It has been approved by various governments and organizations for securing sensitive data.
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