First published 2013 Structure ARX | Related to | |
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Designers Ray Beaulieu, Douglas Shors, Jason Smith, Stefan Treatman-Clark, Bryan Weeks, Louis Wingers NSA Key sizes 64, 72, 96, 128, 144, 192 or 256 bits Block sizes 32, 48, 64, 96 or 128 bits | ||
Speck is a family of lightweight block ciphers publicly released by the National Security Agency (NSA) in June 2013. Speck has been optimized for performance in software implementations, while its sister algorithm, Simon, has been optimized for hardware implementations. Speck is an add-rotate-xor (ARX) cipher.
Speck supports a variety of block and key sizes. A block is always two words, but the words may be 16, 24, 32, 48 or 64 bits in size. The corresponding key is 2, 3 or 4 words. The round function consists of two rotations, adding the right word to the left word, xoring the key into the left word, then and xoring the left word to the right word. The number of rounds depends on the parameters selected, as follows:
The key schedule uses the same round function as the main block cipher.