ISO/IEC 29150:2011 情報技術—セキュリティ技術—署名暗号化 | ページ 6

3.1

asymmetric cipher

alternative term for asymmetric encryption system

[SOURCE:ISO/IEC 18033-1:2005]

3.2

asymmetric cryptographic technique

cryptographic technique that uses two related transformations, a public transformation (defined by the public key) and a private transformation (defined by the private key)

[SOURCE:ISO/IEC 11770-1:2010]

3.3

asymmetric encryption system

system based on asymmetric cryptographic techniques whose public transformation is used for encryption and whose private transformation is used for decryption

[SOURCE:ISO/IEC 9798-1:2010]

3.4

asymmetric key pair

pair of related keys where the private key defines the private transformation and the public key defines the public transformation

[SOURCE:ISO/IEC 9798-1:2010]

3.5

block

string of bits of a defined length

3.6

block cipher

symmetric encryption system with the property that encryption operates on a block of plaintext, i.e. a string of bits of a defined length, to yield a block of ciphertext, and decryption operates on the ciphertext to yield the original plaintext

[SOURCE:ISO/IEC 18033-1:2005]

3.7

cipher

alternative term for encryption system

[SOURCE:ISO/IEC 18033-1:2005]

3.8

ciphertext

data which has been transformed to hide its information content

[SOURCE:ISO/IEC 10116:2006]

3.9

cleartext

alternative term for plaintext

3.10

collision-resistant hash-function

hash-function satisfying the following property: it is computationally infeasible to find any two distinct inputs which map to the same output

[SOURCE:ISO/IEC 10118-1:2000]

3.11

data element

integer or bit string or set of integers or set of bit strings

3.12

decryption

reversal of encryption by a cryptographic algorithm to produce a plaintext

3.13

decryption algorithm

process which transforms a ciphertext into a plaintext

[SOURCE:ISO/IEC 18033-1:2005]

3.14

domain

set of entities operating under a single security policy

[SOURCE:ISO/IEC 14888-1:2008]

3.15

domain parameter

data element which is common to and known by or accessible to all entities within the domain

[SOURCE:ISO/IEC 14888-1:2008]

3.16

encryption

(reversible) transformation of data by a cryptographic algorithm to produce a ciphertext, i.e. to hide the information content of the data

Note 1 to entry: Adapted from ISO/IEC 9797-1:2011.

3.17

encryption algorithm

process which transforms a plaintext into a ciphertext

[SOURCE:ISO/IEC 18033-1:2005]

3.18

encryption system

cryptographic technique used to protect the confidentiality of data, and which consists of three component processes: a method for generating keys, an encryption algorithm and a decryption algorithm

3.19

full domain cryptographic hash function

function that maps strings of bits to integers in a fixed range, satisfying the properties of (1) for a given output, it is computationally infeasible to find an input which maps to this output, and (2) for a given input, it is computationally infeasible to find a second input which maps to the same output

Note 1 to entry: A full domain cryptographic hash function is similar to a standard cryptographic hash function with the exception that the former outputs an integer rather than a bit string; see 7.2.2.

3.20

identification data

sequence of data elements, including the distinguishing identifier for an entity, assigned to an entity and used to identify it

Note 1 to entry: The identification data can additionally contain data elements such as identifier of the signature process, identifier of the signature key, validity period of the signature key, restrictions on key usage, associated security policy parameters, key serial number, or domain parameters.

[SOURCE:ISO/IEC 14888-1:2008]

3.21

key

sequence of symbols that controls the operation of a cryptographic transformation (e.g. encryption, decryption)

[SOURCE:ISO/IEC 11770-1:2010]

3.22

key pair

pair consisting of a public key and a private key associated with an asymmetric cipher

3.23

keystream

pseudorandom sequence of symbols, intended to be secret, used by the encryption and decryption algorithms of a stream cipher

Note 1 to entry: If a portion of the keystream is known by an attacker, then it is computationally infeasible for the attacker to deduce any information about the remainder of the keystream.

3.24

message

string of bits of any length

3.25

n-bit block cipher

block cipher with the property that plaintext blocks and ciphertext blocks are n bits in length

[SOURCE:ISO/IEC 10116:2006]

3.26

one-way hash function

[SOURCE:ISO/IEC 10118-1:2000]

3.27

parameter

integer or bit string or function

3.28

plaintext

unencrypted information

[SOURCE:ISO/IEC 10116:2006]

3.29

private key

that key of a key pair associated with an entity’s asymmetric cipher which is kept secret and used by that entity only

[SOURCE:ISO/IEC 11770-1:2010]

3.30

public key

that key of a key pair associated with an entity’s asymmetric cipher which can be made public and used by any entity

[SOURCE:ISO/IEC 11770-1:2010]

3.31

secret key

key used with symmetric cryptographic techniques by a specified set of entities

[SOURCE:ISO/IEC 11770-3:2008]

3.32

signature

one or more data elements resulting from the signature process

3.33

signature key

set of private data elements specific to an entity and usable only by this entity in the signature process

[SOURCE:ISO/IEC 14888-1:2008]

3.34

signature process

process which takes as inputs the message, the signature key and the domain parameters, and which gives as output the signature

3.35

signcrypt

to apply signcryption on a plaintext

3.36

signcryption

(reversible) transformation of data by a cryptographic algorithm to produce a ciphertext from which no information about the original data can be recovered (except possibly its length), nor can a new ciphertext be forged by an unauthorized entity without detection, that is, it provides data confidentiality, data integrity, data origin authentication, and non-repudiation

Note 1 to entry: Unforgeability implies data integrity, data origin authentication, and non-repudiation.

3.37

signcryption algorithm

one of the three component algorithms of a signcryption mechanism which takes as input a plaintext, a sender’s public and private key pair, a recipient’s public key and other data, outputs a ciphertext after performing a sequence of specified operations on the input

3.38

signcryption mechanism

cryptographic technique used to protect the confidentiality and simultaneously guarantee the origin, integrity and non-repudiation of data, and which consists of three component algorithms: a key generation algorithm, a signcryption algorithm and a unsigncryption algorithm

3.39

signed message

set of data elements consisting of the signature, the part of the message which cannot be recovered from the signature, and an optional text field

[SOURCE:ISO/IEC 14888-1:2008]

3.40

symmetric cipher

cipher based on symmetric cryptographic techniques that uses the same secret key for both the encryption and decryption algorithms

[SOURCE:ISO/IEC 18033-1:2005]

3.41

symmetric cryptographic technique

cryptographic technique that uses the same secret key for both the originator’s and the recipient’s transformation

Note 1 to entry: Without knowledge of the secret key, it is computationally infeasible to compute either the originator’s or the recipient’s transformation.

Note 2 to entry: Examples of symmetric cryptographic techniques include symmetric ciphers and Message Authentication Codes (MACs). In a symmetric cipher, the same secret key is used to encrypt and decrypt data. In a MAC, the same secret key is used to generate and verify MACs.

3.42

unsigncrypt

to apply unsigncryption on a ciphertext

3.43

unsigncryption

verification and decryption of a ciphertext by a cryptographic algorithm

3.44

unsigncryption algorithm

one of the three component algorithms of a signcryption mechanism which takes as input a ciphertext, a recipient’s public and private key pair, a sender’s public key and other data, outputs a pair consisting of either a symbolic value ACCEPT and a plaintext, or a symbolic value REJECT and the null string

3.45

verification key

set of public data elements which is mathematically related to an entity's signature key and which is used by the verifier in the verification process

[SOURCE:ISO/IEC 14888-1:2008]

3.46

verification process

process which takes as input the signed message, the verification key and the domain parameters, and which gives as output the result of the signature verification: valid or invalid

[SOURCE:ISO/IEC 14888-1:2008]