This document specifies three block ciphers suitable for applications requiring lightweight cryptographic implementations:— PRESENT: a lightweight block cipher with a block size of 64 bits and a key size of 80 or 128 bits;— CLEFIA: a lightweight block cipher with a block size of 128 bits and a key size of 128, 192 or 256 bits;— LEA: a lightweight block cipher with a block size of 128 bits and a key size of 128, 192 or 256 bits.