ISO 18033-3 pdf download – lnformation technology -Security techniques – Encryption algorithms一Part 3: Block ciphers

ISO 18033-3 pdf download – lnformation technology -Security techniques – Encryption algorithms一Part 3: Block ciphers.
2.4
key
sequence of symbols that controls the operation of a cryptographic transformation (eg. encipherment, decipherment). LISO/IEC 11770-1:1996)
NOTE — In all the ciphers specified in this part of ISO11EC1BO33, keys consist of a sequence of bits.
2.5
n-bit block cipher
block cipher with the property that pla.ntext blocks and clphertext blocks are n bits In length
[tSO/IEC 101161997]
2.6
plaintext
unenciphered information. (ISO/I EC 9797-1:19991
3 Symbols
n — plaintext/ciphertext bit length for a block cipher.
E – encryption function with key K.
– decryption function with key K.
Nr — the number of rounds for the AES algorithm, which is 10, 12cr 14 for the choices of key length 128, 192 or 256 bits respectively.
Nk — the number of 32-bit words comprising a key for the AES algorithm, which is 4, 6 or 8 for the choices of key length 128. 192 or 256 bits respectively.
— the bit-wise logical exclusive-OR operation on bit-strings, I.e. if A. B are strings of the same length then A B Is the string equal to the bit-wise logical exclusive-OR of A and B.
A —the bit-wise logical AND operation on bit-strings. ie., If A, B are strings ol the same length then A AB is
the string equal to the bit-wise logical AND of A and B.
V — the bit-wise logical OR operation on bit-strings. I.e., If A. B are strings of the same length then A VB Is
the string equal to the bit-wise logical OR of A and B II — concatenation of bit strings.
• — finite field multiplicatIon.
<<‘C — the left circular rotation of the operand by i hits. >>> — the right circular rotation of the operand by i bits.
— the bitwise complement of x.
4 64-bit block ciphers
In this clause, three 64-bit block ciphers are speci1ied TDEA (or ‘Triple DES’) in clause 4.1, MISTYI In cLause 4.2 and CAST-128 m clause 4.3.
Users authorized to access data that has been enciphered must have the key that was used to encipher the data in order to decipher it. The algorithm is designed to encipher and decipher blocks of data consisting 0(64 bits under control of a 128- (or 192-) hit key. Deciphering must be accomplished using the same key as for enciphenng.