Bindings to 'libsodium' <https://doc.libsodium.org/>: a modern, 
    easy-to-use software library for encryption, decryption, signatures, password
    hashing and more. Sodium uses curve25519, a state-of-the-art Diffie-Hellman 
    function by Daniel Bernstein, which has become very popular after it was 
    discovered that the NSA had backdoored Dual EC DRBG.