sssa

README

sssa-golang

An implementation of Shamir's Secret Sharing Algorithm in Go

Copyright (C) 2015 Alexander Scheel, Joel May, Matthew Burket  
See Contributors.md for a complete list of contributors.  
Licensed under the MIT License.  

Usage

Note: this library is for a pure implementation of SSS in Go; if you are looking for the API Library for SSSaaS, look here.

sssa.Create(minimum int, shares int, raw string) - creates a set of shares

sssa.Combine(shares []string) - combines shares into secret

For more detailed documentation, check out docs/sssa.md.

Contributing

We welcome pull requests, issues, security advice on this library, or other contributions you feel are necessary. Feel free to open an issue to discuss any questions you have about this library.

This is the reference implementation for all other SSSA projects. Please make sure all tests pass before submitting a pull request. In particular, go test will run all internal tests and the go-libtest suite's tests should be run against the changes before submission.

For security issues, send a GPG-encrypted email to alexander.m.scheel@gmail.com with public key 0xBDC5F518A973035E.

Documentation

Index

• Constants
• Variables
• func Combine(shares []string) ([]byte, error)
• func Create(minimum int, shares int, raw string) ([]string, error)
• func CreateFromBytes(minimum int, shares int, raw []byte) ([]string, error)
• func IsValidShare(candidate string) bool

Constants

const (
	DefaultPrimeStr = "115792089237316195423570985008687907853269984665640564039457584007913129639747"
)

secure prime number

Variables

var (
	ErrCannotRequireMoreShares = errors.New("cannot require more shares then existing")
	ErrOneOfTheSharesIsInvalid = errors.New("one of the shares is invalid")
)

exported errors

Functions

func Combine

func Combine(shares []string) ([]byte, error)

Combine takes a string array of shares encoded in base64 created via Shamir's Algorithm; each string must be of equal length of a multiple of 88 characters as a single 88 character share is a pair of 256-bit numbers (x, y). Note: the polynomial will converge if the specified minimum number of shares

or more are passed to this function. Passing thus does not affect it
Passing fewer however, simply means that the returned secret is wrong.

func Create

func Create(minimum int, shares int, raw string) ([]string, error)

Create returns a new array of secret shares (encoding x,y pairs as base64 strings) created by Shamir's Secret Sharing Algorithm requring a minimum number of share to recreate, of length shares, from the input secret raw as a string

func CreateFromBytes

func CreateFromBytes(minimum int, shares int, raw []byte) ([]string, error)

CreateFromBytes allows the creation of the shares from an array of bytes

func IsValidShare

func IsValidShare(candidate string) bool

IsValidShare takes in a given string to check if it is a valid secret Requirements: Length multiple of 88

Can decode each 44 character block as base64

Returns only success/failure (bool)