1. A well-defined computational procedure that takes variable inputs, including a cryptographic key, and produces an output.
Source(s):
CNSSI 4009-2015 under cryptographic algorithm (crypto-algorithm) from NIST SP 800-57 Part 1 Rev. 3

  2. Well-defined procedure or sequence of rules or steps, or a series of mathematical equations used to describe cryptographic processes such as encryption/decryption, key generation, authentication, signatures, etc.
Source(s):
CNSSI 4009-2015 under cryptographic algorithm (crypto-algorithm) from NSA/CSS Manual Number 3-16 (COMSEC)

  A well-defined computational procedure that takes variable inputs, often including a cryptographic key, and produces an output.
Source(s):
NIST SP 800-133 [Superseded]
NIST SP 800-133 Rev.1 [Superseded]
NIST SP 800-152

  A well-defined computational procedure that takes variable inputs, including a cryptographic key, and produces an output.
Source(s):
NIST SP 800-57 Part 1 Rev. 4 [Superseded]
NIST SP 800-57 Part 1 Rev. 5
NIST SP 800-57 Part 1 Rev. 3 [Superseded]

  A well-defined computational procedure that takes variable inputs, including a cryptographic key (if applicable), and produces an output.
Source(s):
NIST SP 800-175B Rev. 1