This lesson introduces AES, its origins, and the standards that define and govern its use. These foundations explain why AES became a widely adopted encryption standard.
The Advanced Encryption Standard (AES) is a specification for encrypting electronic data. It is a symmetric-key algorithm: the same secret key is used to encrypt plaintext and decrypt the resulting ciphertext. The sender and recipient therefore need a secure way to share or establish that key.
All flashcards
What is AES?
AES is a standardized symmetric-key block cipher for encrypting electronic data. It uses a 128-bit block and keys of 128, 192, or 256 bits.
What does symmetric-key mean?
It means the same secret key is used to encrypt plaintext and decrypt ciphertext.
Who created Rijndael?
Joan Daemen and Vincent Rijmen, Belgian cryptographers, designed the Rijndael cipher family.
Which standards define AES?
AES is defined in NIST's FIPS PUB 197 and is included in ISO/IEC 18033-3, the block-cipher standard.
How did AES replace DES?
After a five-year NIST selection process evaluating 15 designs, Rijndael was selected and standardized as AES to supersede DES.
Quiz questions
What does it mean that AES is a symmetric-key algorithm?Answer: The same secret key is used for encryption and decryption.
Who designed the Rijndael cipher family on which AES is based?Answer: Belgian cryptographers Joan Daemen and Vincent Rijmen.
Which organization selected Rijndael as the basis for AES?Answer: The US National Institute of Standards and Technology (NIST).
What role does SubBytes play in AES encryption?Answer: It replaces each state byte using a fixed S-box, adding non-linearity.
Why does publication of AES as a standard not, by itself, prove that a product is approved for government use?Answer: A product's cryptographic module and implementation may need separate validation or approval.