Questioning the Criteria for Evaluating Non-Cryptographic Hash Functions

The article discusses the evaluation criteria for non-cryptographic hash functions, emphasizing their widespread use in computing, such as in dictionaries and load balancers. Unlike cryptographic hash functions, which prioritize security and resistance to collisions, non-cryptographic hashes focus on efficiency and uniform distribution of outputs. The authors highlight the importance of testing these functions through practical applications, such as populating hash tables, and demonstrate how different datasets can affect performance. They introduce the avalanche criterion, which states that changing one bit of input should ideally affect every output bit with a 50% probability. The performance of various hash functions, including Murmur2 and FNV, is analyzed against this criterion, revealing that while Murmur2 excels in avalanche performance, it may not always provide optimal collision resistance. The article concludes that every hash function has specific datasets that can challenge its performance, suggesting that the choice of hash function should be tailored to the application's requirements.

- Non-cryptographic hash functions are essential for efficiency in computing tasks.

- The avalanche criterion is a key measure for evaluating hash function performance.

- Practical testing with various datasets reveals strengths and weaknesses in hash functions.

- Murmur2 shows superior avalanche performance but may struggle with collision resistance.

- The choice of hash function should align with specific application needs and data characteristics.