ARIA is a general-purpose block cipher algorithm developed by Korean cryptographers in 2003.ARIA is an iterated block cipher with 128-, 192- and 256-bit keys and encrypts 12-bit blocks in 12, 14 and 16 rounds depending on key size. ARIA is secure and suitable for most software and hardware implementations on 32-bit and 8-bit processors. The ARIA algorithm uses a substitution-permutation network structure based on AES. 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”. All the rules of this algorithm are given in RFC 5794.

An ARIA encryption/decryption apparatus for encrypting and decrypting input data by repeating a plurality of rounds. The ARIA encryption/decryption apparatus comprises of:

  • A first register storing input data according to a first control signal.
  • A second register storing an input round key for every round.
  • An exclusive OR operation unit performing its operation on the values stored in first and second registers.
  • A substitution unit substituting a result of the exclusive OR of an ARIA diffusion algorithm if a current round is not a final round
  • A control unit outputting the first control signals so that the output of the diffusion unit is used as the intermediate calculation value if the current round is not the final round.

Steps Involved in ARIA Algorithm

  • Key Scheduling Part: Here a master key is selected and left and right keys are given bit ranges.
  • Data Randomizing Part: Data Randomizing Part of ARIA algorithm consists of encryption and decryption process. The encryption and decryption processes use functions FO, FE, A, SL1 and SL2.

Advantages of ARIA Encryption Algorithm

  • ARIA Algorithm offers a considerable security margin.
  • The use of ARIA Algorithm within Secure Real Time Transport Protocol provides confidentiality for RTP traffic and also controls RTP traffic.