pbkdf2 0.4.0

This crate implements the PBKDF2 key derivation function as specified in [RFC 2898](https://tools.ietf.org/html/rfc2898). If you are not using convinience functions `pbkdf2_check` and `pbkdf2_simple` it's recommended to disable `pbkdf2` default features in your `Cargo.toml`: ```toml [dependencies] pbkdf2 = { version = "0.2", default-features = false } ```