Respected Svetlin Nakov, I want to contribute to your project by writing code for the following : (a) https://github.com/nakov/Practical-Cryptography-for-Developers-Book/blob/master/mac-and-key-derivation/exercises-password-encryption.md#implement-register-user (b) https://github.com/nakov/Practical-Cryptography-for-Developers-Book/blob/master/mac-and-key-derivation/exercises-password-encryption.md#implement-register-user (c) https://github.com/nakov/Practical-Cryptography-for-Developers-Book/blob/master/mac-and-key-derivation/exercises-password-encryption.md#implement-change-password (d) https://github.com/nakov/Practical-Cryptography-for-Developers-Book/blob/master/mac-and-key-derivation/exercises-password-encryption.md#implement-reset-password Kindly tell me how to contribute. I am starting to code. I hope to hear from you soon. Thanking you in advance.