Part 1: General - Computer Security Resource Center - National ...

Cryptographic key
(key)
March, 2007
A parameter used in conjunction with a cryptographic algorithm that
determines its operation in such a way that an entity with knowledge of
the key can reproduce or reverse the operation, while an entity without
knowledge of the key cannot. Examples include:
1. The transformation of plaintext data into ciphertext data,
2. The transformation of ciphertext data into plaintext data,
3. The computation of a digital signature from data,
4. The verification of a digital signature,
5. The computation of an authentication code from data,
6. The verification of an authentication code from data and a
received authentication code,
7. The computation of a shared secret that is used to derive keying
material.
Cryptographic key One of at least two parameters that have the same security properties
component (key (e.g., randomness) as a cryptographic key; parameters are combined in
component) an Approved security function to form a plaintext cryptographic key
before use.
Cryptographic module The set of hardware, software, and/or firmware that implements
Approved security functions (including cryptographic algorithms and
key generation) and is contained within the cryptographic boundary.
Cryptomodule See cryptographic module.
Cryptoperiod The time span during which a specific key is authorized for use or in
which the keys for a given system or application may remain in effect.
Data integrity A property whereby data has not been altered in an unauthorized
manner since it was created, transmitted or stored.
In this recommendation, the statement that a cryptographic algorithm
"provides data integrity" means that the algorithm is used to detect
unauthorized alterations.
Decryption The process of changing ciphertext into plaintext using a cryptographic
algorithm and key.
Deterministic random An algorithm that produces a sequence of bits that are uniquely
bit generator (DRBG) determined from an initial value called a seed. The output of the DRBG
“appears” to be random, i.e., the output is statistically indistinguishable
from random values. A cryptographic DRBG has the additional
property that the output is unpredictable, given that the seed is not
known. A DRBG is sometimes also called a Pseudo Random Number
Generator (PRNG) or a deterministic random number generator.
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