scope:

ISO/IEC 18033 specifies encryption systems (ciphers) for the purpose of data confidentiality. ISO/IEC 18033-3:2005 specifies block ciphers. A block cipher is a symmetric encipherment system with the property that the encryption algorithm operates on a block of plaintext, i.e. a string of bits of a defined length, to yield a block of ciphertext. ISO/IEC 18033-3:2005 specifies the following algorithms.____ ________64-bit block ciphers: TDEA, MISTY1, CAST-128._________128-bit block ciphers: AES, Camellia, SEED.__________ ___NOTE The primary purpose of encryption (or ___encipherment____) techniques is to protect the confidentiality of stored or transmitted data. An encryption algorithm is applied to data (often called ___plaintext____ or ___cleartext____) to yield encrypted data (or ___ciphertext____); this process is known as ___encryption____. The encryption algorithm is designed so that the ciphertext yields no information about the plaintext except, perhaps, its length. Associated with every encryption algorithm is a corresponding ___decryption algorithm____, which transforms ciphertext back into its original plaintext.