github.com/dedis/crypto/cosi

Advanced crypto library for the Go language


Keywords
crypto-library, elliptic-curves, go
License
MPL-2.0
Install
go get github.com/dedis/crypto/cosi

Documentation

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DEDIS Advanced Crypto Library for Go

This package provides a toolbox of advanced cryptographic primitives for Go, targeting applications like Cothority that need more than straightforward signing and encryption. Please see the Godoc documentation for this package for details on the library's purpose and API functionality.

This package includes a mix of variable time and constant time implementations. If your application is sensitive to timing-based attacks and you need to constrain Kyber to offering only constant time implementations, you should use the suites.RequireConstantTime() function in the init() function of your main package.

Versioning - Development

We use the following versioning model:

  • crypto.v0 was the first semi-stable version. See migration notes.
  • kyber.v1 never existed, in order to keep kyber, onet and cothorithy versions linked
  • gopkg.in/dedis/kyber.v2 was the last stable version
  • Starting with v3.0.0, kyber is a Go module, and we respect semantic versioning.

So if you depend on the master branch, you can expect breakages from time to time. If you need something that doesn't change in a backward-compatible way you should use have a go.mod file in the directory where your main package is.

Installing

First make sure you have Go version 1.11 or newer installed.

The basic crypto library requires only Go and a few third-party Go-language dependencies that can be installed automatically as follows:

go get go.dedis.ch/kyber

You can recursively test all the packages in the library as follows:

go test -v ./...

A note on deriving shared secrets

Traditionally, ECDH (Elliptic curve Diffie-Hellman) derives the shared secret from the x point only. In this framework, you can either manually retrieve the value or use the MarshalBinary method to take the combined (x, y) value as the shared secret. We recommend the latter process for new softare/protocols using this framework as it is cleaner and generalizes across different types of groups (e.g., both integer and elliptic curves), although it will likely be incompatible with other implementations of ECDH. See the Wikipedia page on ECDH.

Reporting security problems

This library is offered as-is, and without a guarantee. It will need an independent security review before it should be considered ready for use in security-critical applications. If you integrate Kyber into your application it is YOUR RESPONSIBILITY to arrange for that audit.

If you notice a possible security problem, please report it to dedis-security@epfl.ch.