ISO/IEC 18033-3:2010

Information technology — Security techniques — Encryption algorithms — Part 3: Block ciphers

ISO/IEC 18033 specifies encryption systems (ciphers) for the purpose of data confidentiality. ISO/IEC 18033-3:2010 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 18033-3:2010 specifies following algorithms: 64-bit block ciphers: TDEA, MISTY1, CAST-128, HIGHT; 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 needs to be 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.

Technologies de l'information — Techniques de sécurité — Algorithmes de chiffrement — Partie 3: Chiffrement par blocs

General Information

• Status: Published
• Publication Date: 13-Dec-2010
• ICS: 35.030 - IT Security
• ICS: 35.040 - Information coding
• Technical Committee: ISO/IEC JTC 1/SC 27 - Information security, cybersecurity and privacy protection
• Drafting Committee: ISO/IEC JTC 1/SC 27/WG 2 - Cryptography and security mechanisms
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 06-Feb-2020

Relations

• Amended By: ISO/IEC 18033-3:2010/Amd 1:2021 - Information technology — Security techniques — Encryption algorithms — Part 3: Block ciphers — Amendment 1: SM4
• Effective Date: 01-Jan-2022
• Revises: ISO/IEC 18033-3:2005 - Information technology — Security techniques — Encryption algorithms — Part 3: Block ciphers
• Effective Date: 30-May-2009

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 18033-3
Second edition
2010-12-15


Information technology — Security
techniques — Encryption algorithms —
Part 3:
Block ciphers
Technologies de l'information — Techniques de sécurité — Algorithmes
de chiffrement
Partie 3: Chiffrement par blocs




Reference number
ISO/IEC 18033-3:2010(E)
©
ISO/IEC 2010

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ISO/IEC 18033-3:2010(E)
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©  ISO/IEC 2010
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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ii © ISO/IEC 2010 – All rights reserved

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ISO/IEC 18033-3:2010(E)
Contents Page
Foreword . v
1 Scope . 1
2 Terms and definitions . 1
3 Symbols . 2
4 64-bit block ciphers . 3
4.1 Introduction . 3
4.2 TDEA . 3
4.2.1 The Triple Data Encryption Algorithm . 3
4.2.2 TDEA encryption/decryption . 3
4.2.3 TDEA keying options . 4
4.3 MISTY1 . 4
4.3.1 The MISTY1 algorithm . 4
4.3.2 MISTY1 encryption . 4
4.3.3 MISTY1 decryption . 5
4.3.4 MISTY1 functions . 5
4.3.5 MISTY1 key schedule . 10
4.4 CAST-128 . 11
4.4.1 The CAST-128 algorithm . 11
4.4.2 CAST-128 encryption . 11
4.4.3 CAST-128 decryption . 11
4.4.4 CAST-128 functions . 11
4.4.5 CAST-128 key schedule . 18
4.5 HIGHT. 20
4.5.1 The HIGHT algorithm . 20
4.5.2 HIGHT encryption . 21
4.5.3 HIGHT decryption . 22
4.5.4 HIGHT functions . 23
4.5.5 HIGHT key schedule . 23
5 128-bit block ciphers . 24
5.1 Introduction . 24
5.2 AES . 24
5.2.1 The AES algorithm . 24
5.2.2 AES encryption . 24
5.2.3 AES decryption . 25
5.2.4 AES transformations . 26
5.2.5 AES key schedule . 30
5.3 Camellia . 32
5.3.1 The Camellia algorithm . 32
5.3.2 Camellia encryption . 32
5.3.3 Camellia decryption . 34
5.3.4 Camellia functions . 37
5.3.5 Camellia key schedule . 43
5.4 SEED . 47
5.4.1 The SEED algorithm . 47
5.4.2 SEED encryption . 47
5.4.3 SEED decryption . 47
5.4.4 SEED functions . 48
5.4.5 SEED key schedule . 50
Annex A (normative) Description of DES . 52
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ISO/IEC 18033-3:2010(E)
A.1 Introduction . 52
A.2 DES encryption . 52
A.3 DES decryption . 52
A.4 DES functions . 52
A.4.1 Initial permutation IP . 52
-1
A.4.2 Inverse initial permutation IP . 54
A.4.3 Function f . 54
A.4.4 Expansion permutation E . 55
A.4.5 Permutation P . 55
A.4.6 S-Boxes . 56
A.5 DES key schedule . 57
Annex B (normative) Object identifiers . 60
Annex C (informative) Algebraic forms of MISTY1 and Camellia S-boxes . 62
C.1 Introduction . 62
C.2 MISTY1 S-boxes . 62
C.2.1 The S-boxes S and S . 62
7 9
C.2.2 MISTY1 S-box S . 62
7
C.2.3 MISTY1 S-box S . 62
9
C.3 Camellia S-boxes . 63
Annex D (informative) Test vectors . 64
D.1 Introduction . 64
D.2 TDEA test vectors . 64
D.2.1 TDEA encryption . 64
D.2.2 DES encryption and decryption . 65
D.3 MISTY1 test vectors . 66
D.4 CAST-128 test vectors . 67
D.5 HIGHT test vectors . 67
D.6 AES test vectors . 67
D.6.1 AES encryption . 67
D.6.2 Key expansion example . 68
D.6.3 Cipher example . 70
D.7 Camellia test vectors . 73
D.7.1 Introduction . 73
D.7.2 Camellia encryption . 73
D.8 SEED test vectors . 75
Annex E (informative) Feature table . 77
Bibliography . 78

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ISO/IEC 18033-3:2010(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members
of ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication
as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 18033-3 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 27, IT Security techniques.
This second edition cancels and replaces the first edition (ISO/IEC 18033-3:2005), which has been
technically revised. It also incorporates the Technical Corrigenda ISO/IEC 18033-3:2005/Cor.1:2006,
ISO/IEC 18033-3:2005/Cor.2:2007 and ISO/IEC 18033-3:2005/Cor.3:2008.
ISO/IEC 18033 consists of the following parts, under the general title Information technology — Security
techniques — Encryption algorithms:
⎯ Part 1: General
⎯ Part 2: Asymmetric ciphers
⎯ Part 3: Block ciphers
⎯ Part 4: Stream ciphers
© ISO/IEC 2010 — All rights reserved v

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INTERNATIONAL STANDARD ISO/IEC 18033-3:2010(E)

Information technology — Security techniques — Encryption
algorithms —
Part 3:
Block ciphers
1 Scope
This part of ISO/IEC 18033 specifies block ciphers. A block cipher maps blocks of n bits to blocks of n bits,
under the control of a key of k bits. A total of seven different block ciphers are defined. They are
categorized in 98H96H96H96HTable 1.
Table 1 — Block ciphers specified
Block length Algorithm name  (see #) Key length
  TDEA (97H97H97H4.2) 128 or 192 bits
   MISTY1 (98H98H98H4.3)
64 bits
  CAST-128 (99H99H99H4.4) 128 bits
  HIGHT (100H100H100H4.5)
  AES (101H101H101H5.2)
128, 192 or 256 bits
128 bits   Camellia (102H102H102H5.3)
  SEED (103H103H103H5.4)
128 bits

The algorithms specified in this part of ISO/IEC 18033 have been assigned object identifiers in accordance
with ISO/IEC 9834. The list of assigned object identifiers is given in Annex B. Any changes to the
specification of the algorithms resulting in a change of functional behaviour will result in a change of the
object identifier assigned to the algorithm.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
block
string of bits of defined length
NOTE In this part of ISO/IEC 18033, the block length is either 64 or 128 bits.
[ISO/IEC 18033-1:2005]
2.2
block cipher
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 18033-1:2005]
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ISO/IEC 18033-3:2010(E)

2.3
ciphertext
data which has been transformed to hide its information content
[ISO/IEC 9798-1:1997]
2.4
key
sequence of symbols that controls the operation of a cryptographic transformation (e.g. encipherment,
decipherment)
NOTE In all the ciphers specified in this part of ISO/IEC 18033, keys consist of a sequence of bits.
[ISO/IEC 11770-1:1996]
2.5
n-bit block cipher
block cipher with the property that plaintext blocks and ciphertext blocks are n bits in length
[ISO/IEC 10116:2006]
2.6
plaintext
unenciphered information
[ISO/IEC 9797-1:1999]
3 Symbols
n  plaintext/ciphertext bit length for a block cipher
E  encryption function with key K
K
D  decryption function with key K
K
Nr the number of rounds for the AES algorithm, which is 10, 12 or 14 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
4
⊗ multiplication of two polynomials (each with degree < 4) modulo x + 1
∧ the bit-wise logical AND 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 AND of A and B
∧
∨ the bit-wise logical 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 OR of A and B
||  concatenation of bit strings
•  finite field multiplication
<<<  the left circular rotation of the operand by i bits
i
>>> the right circular rotation of the operand by i bits
i
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ISO/IEC 18033-3:2010(E)
x  the bitwise complement of x
a mod n for integers a and n, (a mod n) denotes the (non-negative) remainder obtained when a is
divided by n. Equivalently if b = a mod n, then b is the unique integer satisfying:
(i) 0 ≤ b < n, and
(ii) (b-a) is an integer multiple of n
 addition in modular arithmetic, i.e., if A, B are t-bit strings then A B is defined to equal (A+B
t
mod 2 )
 subtraction in modular arithmetic, i.e., if A, B are t-bit strings then A B is defined to equal (A-B
t
mod 2 )

4 64-bit block ciphers
4.1  Introduction
In this clause, four 64-bit block ciphers are specified; TDEA (or ‘Triple DES’) in 104H104H104H4.2, MISTY1 in 105H105H105H4.3,
CAST-128 in 4.4, and HIGHT in 4.5.
Users authorized to access data that has been enciphered shall have the key that was used to encipher the
data in order to decipher it. The algorithm for any cipher in this clause is designed to encipher and decipher
blocks of data consisting of 64 bits under control of a 128- (or 192-) bit key. Deciphering shall be
accomplished using the same key as for enciphering.

4.2  TDEA
4.2.1 The Triple Data Encryption Algorithm
The Triple Data Encryption Algorithm (TDEA) is a symmetric cipher that can process data blocks of 64 bits,
using cipher keys with length of 128 (or 192) bits, of which 112 (or 168) bits can be chosen arbitrarily, and
the rest may be used for error detection. The TDEA is commonly known as Triple DES (Data Encryption
Standard).
A TDEA encryption/decryption operation is a compound operation of DES encryption and decryption
operations, where the DES algorithm is specified in Annex A. A TDEA key consists of three DES keys.
4.2.2 TDEA encryption/decryption
4.2.2.1 Encryption/decryption definitions
The TDEA is defined in terms of DES operations, where E is the DES encryption operation for the key K
K
and D is the DES decryption operation for the key K.
K
4.2.2.2 TDEA encryption
The transformation of a 64-bit block P into a 64-bit block C is defined as follows:
C = E (D (E (P))) .
K K K
3 2 1

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ISO/IEC 18033-3:2010(E)
4.2.2.3 TDEA decryption
The transformation of a 64-bit block C into a 64-bit block P is defined as follows:
P = D (E (D (C))) .
K K K
1 2 3
4.2.3 TDEA keying options
This part of ISO/IEC 18033 specifies the following keying options for TDEA. The TDEA key comprises the
triple (K , K , K ).
1 2 3
1. Keying Option 1: K , K and K are different DES keys;
1 2 3
2. Keying Option 2: K and K are different DES keys and K = K .
1 2 3 1
NOTE The option that K = K = K , the single-DES equivalent, is not recommended. Furthermore, the use of
1 2 3
keying option 1 is preferred over keying option 2 since it provides additional security at the same performance level
(see [3] for further details).
4.3  MISTY1
4.3.1 The MISTY1 algorithm
The MISTY1 algorithm is a symmetric block cipher that can process data blocks of 64 bits, using a cipher
key with length of 128 bits.
4.3.2 MISTY1 encryption
The encryption operation is as shown in Figure 1. The transformation of a 64-bit block P into a 64-bit block C
is defined as follows (KL, KO and KI are keys):
(1) P = L || R
0 0
KL = KL || KL || … || KL
1 2 10
KO = KO || KO || … || KO
1 2 8
KI = KI || KI || … || KI
1 2 8
(2) for i = 1, 3, …, 7 (increment in steps of 2 because the loop body consists of two rounds):
R = FL(L , KL )
i i-1 i
    L = FL(R , KL ) ⊕ FO(R , KO , KI )
i i-1 i+1 i i i
    L = R ⊕ FO(L , KO , KI )
i+1 i i i+1 i+1
    R = L
i+1 i
for i = 9:
     R = FL(L , KL )
i i-1 i
     L = FL(R , KL )
i i-1 i+1
(3) C = L || R
9 9
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ISO/IEC 18033-3:2010(E)
4.3.3 MISTY1 decryption
The decryption operation is as shown in Figure 2, and is identical in operation to encryption apart from the
following two modifications.
-1
(1) All FL functions are replaced by their inverse functions FL .
(2) The order in which the subkeys are applied is reversed.
4.3.4 MISTY1 functions
4.3.4.1 MISTY1 function definitions
-1
The MISTY1 algorithm uses a number of functions, namely S , S , FI, FO, FL and FL , which are now
7 9
defined.
4.3.4.2 Function FL
The FL function is used in encryption only and is shown in Figure 3. The FL function is defined as follows (X
and Y are data, KL is a key):
(1) X = X || X , KL = KL || KL
32 L R i iL iR
(2) Y = (X ∧ KL ) ⊕ X
R L iL R
(3) Y = X ⊕ (Y ∨ KL )
L L R iR
(4) Y = Y || Y
32 L R
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ISO/IEC 18033-3:2010(E)
Plaintext Ciphertext


KL1 KL2 KL10 KL9
-1 -1

FL FL
FL FL
KO1,KI1 KO8,KI8


FO FO

KO2,KI2 KO7,KI7


FO FO

KL3 KL4 KL8 KL7
-1 -1

FL FL
FL FL
KO3,KI3 KO6,KI6


FO FO

KO4,KI4 KO5,KI5


FO FO

KL5 KL6 KL6 KL5
-1 -1
FL FL
FL FL
KO5,KI5 KO4,KI4


FO FO

KO6,KI6 KO3,KI3


FO FO

KL7 KL8 KL4 KL3
-1 -1
FL FL FL FL
KO7,KI7 KO2,KI2


FO FO

KO8,KI8 KO1,KI1


FO FO

KL9 KL10 KL2 KL1
-1 -1

FL FL
FL FL



Ciphertext Plaintext

Figure 1 — The Encryption Procedure    Figure 2 — The Decryption Procedure

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ISO/IEC 18033-3:2010(E)
-1
4.3.4.3 Function FL
-1
The FL function, which is the inverse to the FL function, is used in decryption only and is shown in Figure 4.
-1
The FL function is defined as follows (X and Y are data, KL is a key):
(1) Y = Y || Y , KL = KL || KL
32 L R i iL iR
(2) X = Y ⊕ (Y ∨ KL )
L L R iR
(3) X = (X ∧ KL ) Y
⊕
R L iL R
(4) X = X || X
32 L R
4.3.4.4 Function FO
The FO function is used in encryption and decryption, and is shown in Figure 5. The FO function is defined
as follows (X and Y are data, KO and KI are keys):
(1) X = L || R
32 0 0
KO = KO || KO || KO || KO , KI = KI || KI || KI
i i1 i2 i3 i4 i i1 i2 i3
(2) for j = 1 to 3 :
R = FI(L ⊕ KO , KI ) ⊕ R
j j-1 ij ij j-1
L = R
j j-1
(3) Y = (L ⊕ KO ) || R
32 3 i4 3
4.3.4.5 Function FI
The FI function is used for encryption, decryption and the key schedule, and is shown in Figure 6, where
Extnd is the operation zero-extended from 7 bits to 9 bits by the concatenation of two bits on the left side,
and Trunc is the operation truncated by two bits on the left side. The FI function is defined as follows (X and
Y are data, KI is a key):
(1) X = L (9 bits) || R (7 bits), KI = KI || KI
16 0 0 ij ijL ijR
(2) R = S (L ) ⊕ Extnd(R )
1 9 0 0
(3) L =R
1 0
(4) R = S7(L ) ⊕ Trunc(R ) ⊕ KI
2 1 1 ijL
(5) L = R ⊕ KI
2 1 ijR
(6) R = S (L ) ⊕ Extnd(R )
3 9 2 2
(7) L = R
3 2
(8) Y = L || R
16 3 3
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ISO/IEC 18033-3:2010(E)

X32 Y32
X X Y Y
L R L R

KLiL KLiR


KLiR KLiL




YL YR XL XR
Y32 X32

-1
Figure 3 — The Function FL          Figure 4 — The Function FL



X32 X16
L R L R
0 0 0 0

KO
i1

KI
i1 FI S9

Extnd


KOi2


KIi2 FI S
7

Trunc

KIijL KIijR


KOi3

KI FI S
i3 9

Extnd



KOi4


Y32 Y16

Figure 5 — The Function FO          Figure 6 — The Function FI

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ISO/IEC 18033-3:2010(E)
4.3.4.6 Lookup Tables S and S
7 9
S is a bijective lookup table that accepts a 7-bit input and yields a 7-bit output. S is a bijective lookup table
7 9
that accepts a 9-bit input and yields a 9-bit output. Tables 2 and 3 define these lookup tables in a
hexadecimal form. S and S can be also described in a simple algebraic form over GF(2) as shown in
7 9
clause C.2.
For example, if the input to S is {53}, then the substitution value would be determined by the intersection of
7
the row with index ‘5’ and the column with index ‘3’ in Table 2. This would result in S having a value of {57}.
7

Table 2 — S
7
0 12 3 4 56789a bcd e f
0 1b 32 33 5a 3b 10 17 54 5b 1a 72 73 6b 2c 66 49
1 1f 24 13 6c 37 2e 3f 4a 5d 0f 40 56 25 51 1c 04
2 0b 46 20 0d 7b 35 44 42 2b 1e 41 14 4b 79 15 6f
3 0e 55 09 36 74 0c 67 53 28 0a 7e 38 02 07 60 29
4 19 12 65 2f 30 39 08 68 5f 78 2a 4c 64 45 75 3d
5 59 48 03 57 7c 4f 62 3c 1d 21 5e 27 6a 70 4d 3a
6 01 6d 6e 63 18 77 23 05 26 76 00 31 2d 7a 7f 61
7 50 22 11 06 47 16 52 4e 71 3e 69 43 34 5c 58 7d

Table 3 — S
9
0 1 2 3 4 5 6 7 8 9 a b c d e f
00 1c3 0cb 153 19f 1e3 0e9 0fb 035 181 0b9 117 1eb 133 009 02d 0d3
01 0c7 14a 037 07e
...