About MURMUR3C hash
MurmurHash is a family of non-cryptographic hash functions developed by Austin Appleby, and Murmur3 is a specific variant within this family known for its speed and efficiency in generating well-distributed hash values. Murmur3 has two main variants: Murmur3A and Murmur3B. Murmur3C, however, does not typically refer to a distinct variant of MurmurHash. It's possible there might be confusion or misinformation regarding Murmur3C.
To clarify:
Murmur3A: This variant processes data in 32-bit (4 bytes) or 64-bit (8 bytes) chunks and is designed for generating a 32-bit or 64-bit hash output, respectively. It uses a seed value for initialization and incorporates a mix of bitwise rotations, XOR operations, and multiplication with a prime constant to achieve good dispersion of hash values.
Murmur3B: This variant of Murmur3 is optimized for 128-bit hash output. It improves upon Murmur3A by adding a finalization step that mixes the bits further to enhance the avalanche effect and distribution of the hash values.
Characteristics of Murmur3A and Murmur3B
Output Size: Murmur3A can produce 32-bit or 64-bit hash values, while Murmur3B produces a fixed 128-bit hash value.
Initialization: Both variants use an initial seed value for hash calculation, allowing users to control the starting point of the hash computation.
Hash Calculation: Murmur3A and Murmur3B both process data in chunks and apply specific mixing functions to each chunk, ensuring that small changes in input data result in significantly different hash values (avalanche effect).
Usage and Implementation
Applications: MurmurHash, including Murmur3 variants, is widely used in applications requiring fast and efficient hash functions, such as hash tables, hash-based lookups, and data partitioning in distributed systems.
Implementation: Implementing Murmur3A or Murmur3B is straightforward due to their well-defined algorithms, making them popular choices in software libraries and frameworks.
Security Considerations
- MurmurHash, including Murmur3A and Murmur3B, is designed for speed and distribution but is not suitable for cryptographic purposes due to its predictability and susceptibility to collision attacks.
Summary
While Murmur3C isn't a recognized variant within the MurmurHash family, Murmur3A and Murmur3B are well-established hash functions known for their efficiency and reliability in generating hash values for non-cryptographic purposes. They are favored in scenarios where quick computation and good distribution of hash values are paramount, but where cryptographic security is not required.