Differences Between Rijndael and AES

Question

I'm investigating encryption algorithms - can someone give me a quick rundown of the differences between Rijndael and AES?

Answer 1

AES is a United States federal standard, FIPS 197, which is a subset of Rijndael:

AES has a fixed block size of 128 bits and a key size of 128, 192, or 256 bits, whereas Rijndael can be specified with block and key sizes in any multiple of 32 bits, with a minimum of 128 bits and a maximum of 256 bits.

From Advanced Encryption Standard on Wikipedia.

Answer 2

Strictly speaking, the Advanced Encryption Standard (AES) is not an algorithm. AES is a specification defined by the National Institute of Standards & Technology of the United States (NIST). AES is the successor of the Data Encryption Standard (DES).

AES has been announced in FIPS PUB 197 on November 26, 2001. Federal Information Processing Standards Publications (FIPS PUB) are issued by NIST after approval by the US Secretary of Commerce.

Rijndael is a symmetric key encryption algorithm created by Joan Daemen and Vincent Rijmen. It is a block cipher, with variable block size, variable key length & variable round number. Block length and key length can be independently specified to any multiple of 32 bits from 128 bits to 256 bits.

The Rijndael cipher as been selected as the Advanced Encryption Standard (AES).

In the Rijndael AES variant the block size is restricted to 128 bits and key length to 128, 192 or 256 bits only.

• NIST document on naming for AES/Rijndael
• NIST FIPS PUB 197

Answer 3

Actually in the crisis of 3DES(Triple Data Encryption Standard) NIST decided to establish a new standard. AES is the standard actually taken by the algorithm based on Rijndael algo which is nothing but the combination of two research scientists name Dr. Rijmen and Dr. Daemen according to the algo they fixed the size of the block length to 128bits and the key size also 128 or 256 bit. Later at standardization it is mentioned in Advanced Encryption Technique (AES) that the symmetric block cipher with 128 bits can support 128,192 and 256 bits or 16,24 and 32 byte

Answer 4

AES is a reduced version of Rijndael where it is only defined for block sizes of 128 bit whereas Rijndael is defined for block sizes of 128, 192 and 256 bit. If a different block size between encryption and decryption is used, then it is not possible to recover the original plaintext.

Rijndael-256 and Rijndael-192 must be seen as completely different algorithms from AES (Rijndael-128). They are inherently incompatible.