Differential cryptanalysis can break 46 rounds of Simon128/128 with 2125.6 data, 240.6 bytes memory and time complexity of 2125.7 with success rate of 0.632.
Simon is a family of lightweight block ciphers publicly released by the NSA in June 2013. Simon has been optimized for performance in hardware implementations, while its sister algorithm, Speck, has been optimized for software implementations. Simon is a balanced Feistel cipher.
Simon supports the following combinations of block sizes, key sizes and number of rounds: