key_management/algorithms

9 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.

NIST cryptographic hash function standards

According to NIST SP 800-57 Part 1, hash functions are used in digital signature algorithms (FIPS186), Keyed-Hash Message Authentication Codes HMAC (FIPS198), key-derivation functions/methods (NIST SP 800-56A, 800-56B, 800-56C and 800-108), and random number generators (NIST SP 800-90A). Approved hash functions are defined in FIPS180.

NIST approved cryptographic algorithm classes

NIST SP 800-57 Part 1 recognizes three basic classes of approved cryptographic algorithms: hash functions, symmetric-key algorithms and asymmetric-key algorithms, defined by the number of cryptographic keys used in conjunction with the algorithm.

NSA Commercial National Security Algorithm Suite 2.0

The NSA released the Commercial National Security Algorithm Suite 2.0 which lists cryptographic algorithms expected to remain strong even with advances in quantum computing.

Cryptographic hash functions characteristics and uses

Cryptographic hash functions do not require keys. They generate a relatively small digest from a possibly large input in a way that is fundamentally difficult to reverse. Hash functions are used as building blocks for key management: (1) To provide data authentication and integrity services through message authentication codes, (2) To compress messages for digital signature generation and verification, (3) To derive keys in key-establishment algorithms, (4) To generate deterministic random numbers.

Symmetric-key algorithm characteristics

Symmetric-key algorithms (secret-key algorithms) transform data in a way fundamentally difficult to undo without knowledge of a secret key. The same key is used for a cryptographic operation and its inverse (e.g., encryption and decryption). Symmetric keys are often known by more than one entity; however, the key shall not be disclosed to unauthorized entities. Symmetric key algorithms provide: (1) Data confidentiality where the same key encrypts and decrypts data, (2) Authentication and integrity services as Message Authentication Codes (MACs) using the same key, (3) Support for key-establishment processes, (4) Deterministic random number generation.

Asymmetric-key algorithm characteristics

Asymmetric-key algorithms (public-key algorithms) use two related keys (a key pair): a public key and a private key. The public key may be known by anyone; the private key should be under sole control of the entity that owns the key pair. Knowledge of the public key does not reveal the private key. Asymmetric algorithms are used for: (1) Computing digital signatures, (2) Establishing cryptographic keying material, (3) Generating random numbers.

Message Authentication Codes (MACs) purpose and use

Message Authentication Codes (MACs) provide data authentication and integrity. A MAC is a cryptographic checksum on data used to provide assurance that data has not changed and that the MAC was computed by the expected entity. MACs using approved cryptographic mechanisms prevent alteration by adversaries. MACs provide recipients with assurance that the originator is a key holder (entity authorized to have the key). MACs often authenticate the originator to recipient when only those two parties share the MAC key.

Digital signatures standard and purpose

Digital signatures provide authentication, integrity and non-repudiation. They are used with hash functions and computed on data of any length up to a limit determined by the hash function. FIPS186 specifies algorithms approved for digital signature computation.

Key Encryption Keys purpose

Symmetric key-wrapping keys encrypt other keys using symmetric-key algorithms. Key-wrapping keys are also known as key encrypting keys.

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