File Hashing Techniques in Elixir

The article elaborates on hashing as a method for generating a fixed-size digest from variable size data, similarly to creating a unique digital fingerprint. It starts by explaining the utility of file hashes for integrity checks and differentiates between various hash functions. The author initially presented examples using the MD5 algorithm, but later updated the examples to utilize SHA-256 in light of new CPUs' capabilities. The post progresses to describe how to hash strings and files in Elixir, notably avoiding loading entire file contents into memory. Instead, the author recommends using a stream-based approach with `File.stream!` and the functions within the `:crypto` Erlang module. The process of hashing a file is broken down into initialization, updating with chunks of file data, and finalizing to obtain the hash digest. The text includes code examples that illustrate the hashing process step by step. A benchmark comparison between chunk streaming and line streaming highlights the efficiency gained from chunk-based processing. The piece concludes with recommendations for handling passwords securely using encryption libraries such as bcrypt_elixir rather than relying solely on hashing functions.