A library that wraps part of djb’s NaCl “networking and cryptography” library.
Find out more about that project at nacl.cace-project.eu.
This library requires MRI Ruby 1.8 or 1.9. It should work anywhere where NaCl compiles (most UNIXes).
You must first install the NaCl C library before installing the gem. If you use homebrew on OS X, this is as simple as:
brew install nacl
gem install nacl
Want to provide authenticated encryption? Easy:
alice_pub, alice_sec = NaCl.crypto_box_keypair bob_pub, bob_sec = NaCl.crypto_box_keypair # Alice and Bob exchange their public keys. # Now Alice can make a message for Bob: nonce = SecureRandom.random_bytes(NaCl::BOX_NONCE_LENGTH) ciphertext = NaCl.crypto_box("Meet me at the park at midnight", nonce, bob_pub, alice_sec) # Alice then sends [ciphertext, nonce] to Bob and he can decrypt: NaCl.crypto_box_open(ciphertext, nonce, alice_pub, bob_sec) # => "Meet me at the park at midnight"
Just want to sign the text, but not encrypt it? No problem:
alice_pub, alice_sec = NaCl.crypto_sign_keypair # Alice sends Bob her public key. # Now Alice can make a message for Bob: signed_text = NaCl.crypto_sign("Meet me at the park at midnight", alice_sec) # Alice then sends [signed_text, nonce] to Bob and he can validate the signature: NaCl.crypto_sign_open(signed_text, alice_pub) # => "Meet me at the park at midnight" NaCl.crypto_sign_open(signed_text.gsub("park", "bus stop"), alice_pub) # raises NaCl::OpenError
Secret key encryption requires that the two parties share a key beforehand using some secure channel.
key = SecureRandom.random_bytes(NaCl::SECRETBOX_KEY_LENGTH) # Alice and Bob share the key by some secure means. # Now Alice can make a message for Bob: nonce = SecureRandom.random_bytes(NaCl::BOX_NONCE_LENGTH) ciphertext = NaCl.crypto_secretbox("Meet me at the park at midnight", nonce, key) # Alice then sends [ciphertext, nonce] to Bob and he can decrypt: NaCl.crypto_secretbox_open(ciphertext, nonce, key) # => "Meet me at the park at midnght"
This wrapper library licensed under the MIT licence. Copyright 2012 Roger Nesbitt.