Frequently Asked Questions

Q: I already have a Crypto class this conflicts with. What should I do?

A: Delete your Crypto class and use RbNaCl instead. Trust me.

Q: What about https://github.com/mogest/nacl ?

A: This is a partial NaCl binding which uses the C extension API and therefore doesn't work across all Ruby VMs (e.g. JRuby).

RbNaCl is a complete NaCl binding designed to work everywhere via Ruby FFI. RbNaCl fully supports JRuby and all other Ruby VMs which implement FFI.

Q: Is there any way to decrypt a Crypto::Box message with only a private key without requiring the public key of the sender?

A: Nope. And there probably never will be. This is an integral part of how the Curve25519 algorithm operates, and a design principle you should consider whenever using public key cryptography.

Q: Is there any kind of streaming API for Crypto::Box/Crypto::SecretBox?

A: No. This would involve presenting you with decrypted ciphertext which has not been authenticated. If you need to encrypt a plaintext so large it can't reasonably fit in RAM, consider breaking it into chunks which you encrypt with separate keys and/or nonces. Each block of plaintext you encrypt will have its own MAC to authenticate it and can be safely decrypted in isolation, unlike trying to decrypt only a portion of data inside of a Crypto::(Secret)Box