password_hash_plus
This plugin is a null-safety version of password_hash, you can use it if you need Flutter 2.x and above.
Implements PBKDF2 algorithm for securely hashing passwords.
Usage:
var generator = new PBKDF2();
var salt = Salt.generateAsBase64String();
var hash = generator.generateKey("mytopsecretpassword", salt, 1000, 32);