XXH32 hash

 

About XXH32 hash

XXH32 (or xxHash32) is a non-cryptographic hash function known for its extremely fast hashing speed while maintaining good distribution of hash values. It belongs to the xxHash family developed by Yann Collet and is designed to provide a 32-bit hash output.

Characteristics of XXH32

  1. Output Size:

    • XXH32 produces a fixed-length output of 32 bits (4 bytes).

  2. Initialization Value:

    • XXH32 uses an initial seed value (seed) for hash calculation. This seed can be any arbitrary value chosen by the user to control the starting point of the hash computation.

  3. Hash Calculation:

    • XXH32 processes the input data in blocks of 4 bytes (32 bits) at a time.
    • It applies a mix of bitwise rotations, XOR operations, and multiplications with prime constants to each block of data.
    • The hash state is updated iteratively for each processed block until all data is processed.

  4. Properties:

    • XXH32 is optimized for speed and efficiency, making it suitable for applications requiring rapid computation of hash values.
    • It is deterministic and produces the same hash value for identical input data and seed.
    • XXH32 is not designed for cryptographic purposes due to its predictable nature and vulnerability to collision attacks.

Usage

  • Applications: XXH32 is commonly used in applications where fast hash computation is crucial, such as hash tables, data deduplication, checksums, and non-cryptographic hash-based operations.

  • Implementation: Implementing XXH32 is straightforward due to its simple algorithm and efficient in terms of computational resources.

Example Calculation

Given a sequence of bytes data and an initial seed seed, the XXH32 hash XXH32(data, seed) is calculated as follows:

  • Initialize the hash value hash with the seed value.
  • Process each 4-byte block of data using specific mixing operations.
  • Finalize the hash value to ensure good dispersion and avalanche effect.
  • The final XXH32 hash value after processing all data blocks is returned.

Security Considerations

  • XXH32 is not suitable for cryptographic purposes due to its vulnerability to collision attacks and its predictable nature.
  • It should only be used in scenarios where speed and good distribution of hash values are more critical than cryptographic security.

Summary

XXH32 (xxHash32) is a fast and efficient non-cryptographic hash function designed for rapid computation of 32-bit hash values. It is widely adopted in various software applications and systems where quick hash computation with good dispersion properties is required. However, it should not be used for cryptographic applications where strong security guarantees are needed.