CityHash is a family of non-cryptographic hash functions optimized for extremely fast and high-quality hashing of strings on modern CPUs. Developed by Google, it is implemented in C++ and designed to efficiently handle both short and long inputs using techniques such as mixing operations and CPU-specific optimizations. CityHash offers multiple hash sizes—32-bit, 64-bit, 128-bit, and 256-bit variants—with the CRC-based versions leveraging hardware acceleration on CPUs that support SSE4.2 CRC32 instructions. The library emphasizes hashing performance and uniformity rather than cryptographic security, making it ideal for use in data structures like hash tables and distributed systems requiring rapid key lookups. CityHash has been rigorously tested using tools like SMHasher to ensure high-quality mixing and collision resistance across a wide range of inputs. Its speed and portability have made it a popular choice for developers needing dependable, lightweight hash functions.
Features
- High-performance non-cryptographic hash functions for strings and binary data
- Supports 32-bit, 64-bit, 128-bit, and 256-bit output variants
- Optimized for little-endian 64-bit CPUs, with CRC32 acceleration on supported hardware
- Thoroughly tested for hash quality and collision resistance using SMHasher
- Portable C++ implementation compatible with various compilers and platforms
- Ideal for hash tables, caching systems, and general-purpose string hashing
Project Samples
