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In cryptography, ARIA is a block cipher designed in 2003 by a large group of South Korean researchers. In 2004, the Korean Agency for Technology and Standards selected it as a standard cryptographic technique.

First published 2003
Derived from AES
Certification South Korean standard
Cipher detail
Key sizes 128, 192, or 256 bits
Block sizes 128 bits
Structure Substitution-permutation network
Rounds 12, 14, or 16
Best public cryptanalysis
Meet-in-the-middle attack on 8 rounds with data complexity 256

The algorithm uses a substitution-permutation network structure based on AES. The interface is the same as AES: 128-bit block size with key size of 128, 192, or 256 bits. The number of rounds is 12, 14, or 16, depending on the key size. ARIA uses two 8×8-bit S-boxes and their inverses in alternate rounds; one of these is the Rijndael S-box.

The key schedule processes the key using a 3-round 256-bit Feistel cipher, with the binary expansion of 1/π as a source of "nothing up my sleeve numbers".


  • KATS
    • KS X 1213:2004
  • IETF
    • Algorithm
      • RFC 5794: A Description of the ARIA Encryption Algorithm
    • TLS/SSL
      • RFC 6209: Addition of the ARIA Cipher Suites to Transport Layer Security (TLS)


External linksEdit