Introduction

GoSodium is a (work-in-progress) Go language binding for the LibSodium cryptography library. LibSodium is a cross-platform port of the NaCL library published by Dan Bernstein and company implementing the 25519 elliptic curve. These cryptographic methods, and these libraries, are highly regarded as fast, secure, and free of governmental influences.

This package is primarily for personal use as an excuse to learn Go and get more familiar with cryptography and is very much a work-in-progress. If it is useful to others, please feel free to use it, copy it, or contribute to it. If this is a duplicate of other work, please let me know as I am happy to contribute to other projects to avoid redundant efforts.

Status

I am (slowly) wrapping parts of the library as I have time / need so many parts are yet-unwrapped. This table provides a summary of the functionality in each module of the LibSodium library and whether they are included.

Module	Wrap status	Test coverage	Function
crypto_auth	Not wrapped	N/A	Generates a MAC for a given message and secret key using SHA-series hashes (key may be used across multiple messages)
crypto_box	Wrapped	Yes	Encrypts and authenticates a message using a key pair and nonce
crypto_core	Not wrapped	N/A	Core encryption algorithms used by other modules
crypto_generichash	Partially	N/A	Cryptographically secure generic hash function
crypto_hash	Not wrapped	N/A	Hash function based on SHA512 algorithm
crypto_onetimeauth	Wrapped	Yes	Generates a MAC for a given message and shared key using Poly1305 algorithm (key may NOT be reused across messages)
crypto_scalarmult	Partially	N/A	Compute the public key given a secret key previously generated with crypto_box_keypair
crypto_secret_box	Wrapped	Partial	Encrypts and authenticates a message using a shared key and nonce
crypto_sign	Wrapped	N/A	Seals and verifies a message using a key pair
crypto_streaming	Not wrapped	N/A	Generates a randomized stream of bits to be XOR'd with a message
randombytes	Wrapped	Yes	Fills a byte array with cryptographic-quality random values
sodium	Partially	Partial	Initialization and utility methods

Definitions:

• Key Pair: A pair of keys comprised of one public key and one secret key. For example, the sender's secret key and the recipient's public key, or the sender's public key and the recipient's private key.
• Shared key: A single key which is known to both the sender and recipient(s). In LibSodium it is common to generate a shared key from a key pair above. The keys have the property that the symmetric key can be generated from each half of a key pair. That is, Alice's public key plus Bob's secret key can be combined to generate the same key as Bob's public key and Alice's private key.

Getting started on Nitrous.io

One quick way to get started playing with this package is on Nitrous.io. This is one of several cloud-based IDEs that also provide virtual machines to get started with. The VMs seem to be decently performant and the 'parts' utility is a nice way to quickly bootstrap an environment with Go and LibSodium.

Once you have a machine set up:

parts install go
parts install libsodium
go get github.com/neuegram/GoSodium

Installing libsodium puts it in ~/.parts/packages/libsodium-0.6.0. This is the path that is hardcoded into the remaining .go files.

Note: The recipes for Go 1.3 and LibSodium are currently pending PRs (#161, 162) to the Nitrous.io parts GitHub repository (https://github.com/nitrous-io/autoparts/pulls). You will need to explicitly pull these branches until the changes have been merged.

Building and testing GoSodium

Once you have a working environment, go to your Go 'src' directory and run the following commands:

go install github.com/neuegram/GoSodium/sodium
go test github.com/neuegram/GoSodium/sodium
go install github.com/neuegram/GoSodium

If all works as expected, the tests should pass for 'sodium' and everything should be ready for use.

Contact

Questions? Comments? Requests? Complaints? Feel free to contact me here or via Google+ or Twitter (@jasonmccampbell).