Add 'What about password hashing?' to FAQ in README

README.md

@@ -485,6 +485,14 @@ For detailed information on how to read and write session data conveniently, ple
 
 ## Frequently asked questions
 
+### What about password hashing?
+
+Any password or authentication token is automatically hashed using the ["bcrypt"](https://en.wikipedia.org/wiki/Bcrypt) function, which is based on the ["Blowfish" cipher](https://en.wikipedia.org/wiki/Blowfish_(cipher)) and (still) considered one of the strongest password hash functions today. "bcrypt" is used with 1,024 iterations, i.e. a "cost" factor of 10. A random ["salt"](https://en.wikipedia.org/wiki/Salt_(cryptography)) is applied automatically as well.
+
+You can verify this configuration by looking at the hashes in your database table `users`. If the above is true with your setup, all password hashes in your `users` table should start with the prefix `$2$10$`, `$2a$10$` or `$2y$10$`.
+
+When new algorithms (such as [Argon2](https://en.wikipedia.org/wiki/Argon2)) may be introduced in the future, this library will automatically take care of "upgrading" your existing password hashes whenever a user signs in or changes their password.
+
 ### How can I implement custom password requirements?
 
 Enforcing a minimum length for passwords is usually a good idea. Apart from that, you may want to look up whether a potential password is in some blacklist, which you could manage in a database or in a file, in order to prevent dictionary words or commonly used passwords from being used in your application.