MurmurHash3

MurmurHash3 is a non-cryptographic hash function created by Austin Appleby as the successor to MurmurHash2. Published in 2011, it aims to provide fast hashing with good distribution for hash-based data structures rather than cryptographic security. Like its predecessors, MurmurHash3 is designed to be fast on modern CPUs and to produce uniformly distributed outputs for a wide range of inputs.

There are three main variants: MurmurHash3_x86_32, MurmurHash3_x86_128, and MurmurHash3_x64_128. The x86_32 variant outputs 32 bits, while the two 128-bit variants output 128 bits. The algorithms process input in blocks appropriate to the target variant, applying a sequence of mixing operations, rotations, and finalization steps to achieve diffusion. Each variant accepts an initial seed to influence the resulting hash.

Although fast and widely used, MurmurHash3 is not suitable for cryptographic purposes. It is vulnerable to collisions and preimage attacks if security is required. It is commonly employed for non-secure hashing tasks such as hash tables, indexing, deduplication, and checksums in various software libraries and databases. Implementations exist in multiple languages, and the function is valued for its balance of speed and uniform hashing across platforms.