In cryptography, an HMAC (sometimes expanded as either keyed-hash message authentication code or hash-based message authentication code) is a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key.

Feb 8, 2010 · A keyed hash produces an output that depends both on the input data, and a key. If it is cryptographically secure, then it satisfies the above properties of a non-keyed hash, and in addition: There are no known ways faster than bruteforce to find the key used, given a set of input and output pairs produced with that key;

Aug 7, 2023 · What are keyed hash functions? How keyed hash functions work? Imagine you're holding a box with a unique lock, and the only key to open it is a special sequence of numbers and letters. That's pretty much what keyed hash functions are about in the digital world.

Jul 16, 2008 · This Standard describes a keyed-hash message authentication code (HMAC), a mechanism for message authentication using cryptographic hash functions. HMAC can be used with any iterative Approved cryptographic hash function, in combination with a shared secret key.

Nov 14, 2019 · Keyed hashing is usually used to build message authentication codes (MACs), the most common of which is the hashed-based MAC (HMAC). MACs are basically cryptographic checksums. They are used to detect when an attacker has tampered with a message.

Jun 21, 2024 · A keyed-hash function, also known as a message authentication code (MAC), is a cryptographic algorithm that uses a secret key to generate a fixed-size output, or hash value, from a variable-size message.

Jun 28, 2024 · This NIST Special Publication (whose current version is an initial public draft) specifies the keyed-hash message authentication code (HMAC) construction, which is a MAC scheme that uses a cryptographic hash function as a building block.

An algorithm that creates a message authentication code based on both a message and a secret key shared by two endpoints. Also known as a hash message authentication code algorithm. Sources: NIST SP 800-77 Rev. 1

Jan 30, 2013 · However, it so happens that HMAC is built over hash functions, and can be considered as a "keyed hash" -- a hash function with a key. A key is not a salt (keys are secret, salts are not).

Hash function: a mathematical function that maps a string of arbitrary length (up to a pre-determined maximum size) to a fixed length string. Keyed-hash message authentication code (HMAC): a message authentication code that uses a cryptographic key in conjunction with a …