Square (cipher)

{{Short description|Block cipher invented by Joan Daemen and Vincent Rijmen}}

{{Infobox block cipher

| name = Square

| image =

| caption =

| designers = Joan Daemen, Vincent Rijmen

| publish date = 1997

| derived from =

| derived to = AES, CRYPTON, Twofish, Serpent

| key size = 128 bits

| block size = 128 bits

| structure = substitution–permutation network

| rounds = 8

| cryptanalysis =

}}

In cryptography, Square (sometimes written SQUARE) is a block cipher invented by Joan Daemen and Vincent Rijmen. The design, published in 1997, is a forerunner to Rijndael, which has been adopted as the Advanced Encryption Standard. Square was introduced together with a new form of cryptanalysis discovered by Lars Knudsen, called the "Square attack".

The structure of Square is a substitution–permutation network with eight rounds, operating on 128-bit blocks and using a 128-bit key.

Square is not patented.