About 29,200 results
Open links in new tab
  1. 12

    HMAC (Hash-based Message Authentication Code) is a cryptographic technique that ensures data integrity and authenticity using a hash function and a secret key. It is widely used in secure communication protocols like HTTPS, SFTP, and FTPS.

    How HMAC Works

    HMAC involves two passes of hash computation. Initially, the secret key is used to derive two keys: an inner key and an outer key. The first pass of the hash algorithm produces an internal hash derived from the message and the inner key. The second pass produces the final HMAC code derived from the inner hash result and the outer key.

    Here is a simplified pseudocode for HMAC:

    def hmac(key, message, hash_func, block_size):
    if len(key) > block_size:
    key = hash_func(key)
    if len(key) < block_size:
    key = key.ljust(block_size, b'\0')

    o_key_pad = bytearray((x ^ 0x5c) for x in key)
    i_key_pad = bytearray((x ^ 0x36) for x in key)

    return hash_func(o_key_pad + hash_func(i_key_pad + message))
    Copied!

    Example Usage in Python

    Feedback
  2. Wikipedia
    https://en.wikipedia.org › wiki › HMAC

    HMAC - Wikipedia

    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. As with any MAC, it …
    Details

    Any cryptographic hash function, such as SHA-2 or SHA-3, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMAC-x, where x is the hash function used (e.g. HMAC-SHA256 or HMAC-SHA3-512). The cryptographic …

    Implementation

    The following pseudocode demonstrates how HMAC may be implemented. The block size is 512 bits (64 bytes) when using one of the following hash functions: SHA-1, MD5, RIPEMD-128.

    Design principles

    The design of the HMAC specification was motivated by the existence of attacks on more trivial mechanisms for combining a key with a hash function. For example, one might assume the same security that HMAC provides could be achieved with …

    Wikipedia text under CC-BY-SA license
    Feedback
  3. GeeksForGeeks
    https://www.geeksforgeeks.org › computer-network…

    What is HMAC (Hash based Message …

    Jul 12, 2025 · HMAC (Hash-Based Message Authentication Code) is a cryptographic technique that ensures data integrity and authenticity using …

  5. Medium
    https://medium.com › @short_sparrow › how-hmac-…

    How HMAC works, step-by-step explanation | Medium

    Dec 17, 2023 · HMAC (Hash Message Authentication Code) is an approach for creating digital signatures using different hash algorithms like MD5, …

  6. Okta
    https://www.okta.com › hmac

    HMAC (Hash-Based Message Authentication Codes) Definition

    • Nearly every company has sensitive information. If you take in payments of any sort, for example, you likely have credit card data at your fingertips. And if you have employees, you have Social Security numbers that could be stolen. But some companies have even deeper issues. If you're in a heavily regulated environment, such as health care, or you...
    See more on okta.com
  7. People also ask
    Unable to load answer

    Feedback
  8. Peerlist
    https://peerlist.io › jagss › articles › understanding-h…

    Understanding HMAC: A Deep Dive into Hash-Based …

    Jun 11, 2025 · HMAC stands for Hash-based Message Authentication Code. It is a construction that combines a cryptographic hash function with a …

  9. TutorialsPoint
    https://www.tutorialspoint.com › hashed-message-a…

    Hashed Message Authentication Code (HMAC)

    Jan 10, 2023 · HMAC (short for "Keyed-Hash Message Authentication Code") is a cryptographic hash function that uses a secret key as input to the …

  10. NIST Computer Security Resource Center
    https://csrc.nist.gov › projects › message-authentication-codes

    Message Authentication Codes | CSRC

    Jan 4, 2017 · The message authentication code (MAC) is generated from an associated message as a method for assuring the integrity of the message and the authenticity of the source of the …

  11. supertechman.com.au
    https://supertechman.com.au › understanding-mess…

    Understanding Message Authentication Code …

    Aug 18, 2025 · HMAC stands for Hash-based Message Authentication Code. It combines a cryptographic hash function (such as SHA-256, SHA-3, or …

  12. TechTarget
    https://www.techtarget.com › ... › Hash-based-Messa…

    What is HMAC (Hash-Based Message …

    Jun 16, 2025 · Hash-based message authentication code (HMAC) is a message encryption method that uses a cryptographic key with a hash …

  13. Kinde
    https://www.kinde.com › ... › hash-based-message-a…

    What is Hash-Based Message Authentication Codes …

    Aug 11, 2025 · HMAC is a message-based authentication code that uses a …

    • Reviews: 40
    Content was generated with AI. Learn more