How Does the International Data Encryption Algorithm (IDEA) Work?
IDEA works as a block cipher that uses a 128-bit key that is capable of encrypting data into blocks of 64-bits. Consistent with other conventional encryption methods, it begins with two inputs – plaintext and a key. The IDEA algorithm breaks down the inputs into four 16-bit sized blocks. These blocks are then mixed together in multiple rounds. These produce the output blocks, which are then transformed into fifty-two sub-keys. The remaining four 16-bit blocks are then linked to form the ciphertext. Put simply, text is converted into a cipher using 16-bit blocks that are mixed together using multiplication and addition operations. The final result of these operations turns the blocks into garbled code that cannot be deciphered without the use of the fifty-two subkeys.
