From cccce548b3b04081f3bdc70ddc82e403ed611f45 Mon Sep 17 00:00:00 2001
From: arnaucube <arnaucube@gmail.com>
Date: Sat, 13 Apr 2019 02:23:37 +0200
Subject: [PATCH] shamirsecretsharing moved to it's own repository plus wasm
 compiled lib

---
 shamirsecretsharing/README.md                 |  48 +-------
 shamirsecretsharing/shamirsecretsharing.go    | 115 ------------------
 .../shamirsecretsharing_test.go               |  44 -------
 3 files changed, 2 insertions(+), 205 deletions(-)
 delete mode 100644 shamirsecretsharing/shamirsecretsharing.go
 delete mode 100644 shamirsecretsharing/shamirsecretsharing_test.go

diff --git a/shamirsecretsharing/README.md b/shamirsecretsharing/README.md
index ff411d8..f19f793 100644
--- a/shamirsecretsharing/README.md
+++ b/shamirsecretsharing/README.md
@@ -1,48 +1,4 @@
 ## Shamir Secret Sharing
-- https://en.wikipedia.org/wiki/Shamir%27s_Secret_Sharing
+Implementation of the Shamir Secret Sharing in Go + WASM compiled lib
 
-- [x] create secret sharing from number of secrets needed, number of shares, random point p, secret to share
-- [x] Lagrange Interpolation to restore the secret from the shares
-
-#### Usage
-```go
-// define secret to share
-k := 123456789
-
-// define random prime
-p, err := rand.Prime(rand.Reader, bits/2)
-if err!=nil {
-	fmt.Println(err)
-}
-
-// define how many shares want to generate
-nShares := big.NewInt(int64(6))
-
-// define how many shares are needed to recover the secret
-nNeededShares := big.NewInt(int64(3))
-
-// create the shares
-shares, err := Create(
-	nNeededShares,
-	nShares,
-	p,
-	big.NewInt(int64(k)))
-assert.Nil(t, err)
-if err!=nil {
-	fmt.Println(err)
-}
-
-// select shares to use
-var sharesToUse [][]*big.Int
-sharesToUse = append(sharesToUse, shares[2])
-sharesToUse = append(sharesToUse, shares[1])
-sharesToUse = append(sharesToUse, shares[0])
-
-// recover the secret using Lagrange Interpolation
-secr := LagrangeInterpolation(sharesToUse, p)
-
-// check that the restored secret matches the original secret
-if !bytes.Equal(k.Bytes(), secr.Bytes()) {
-	fmt.Println("reconstructed secret not correspond to original secret")
-}
-```
+Code moved to https://github.com/arnaucube/shamirsecretsharing
diff --git a/shamirsecretsharing/shamirsecretsharing.go b/shamirsecretsharing/shamirsecretsharing.go
deleted file mode 100644
index f018aea..0000000
--- a/shamirsecretsharing/shamirsecretsharing.go
+++ /dev/null
@@ -1,115 +0,0 @@
-package shamirsecretsharing
-
-import (
-	"crypto/rand"
-	"errors"
-	"math/big"
-)
-
-const (
-	// bits = 1024
-	bits = 2048
-)
-
-// Create calculates the secrets to share from given parameters
-// t: number of secrets needed
-// n: number of shares
-// p: random point
-// k: secret to share
-func Create(t, n, p, k *big.Int) (result [][]*big.Int, err error) {
-	if k.Cmp(p) > 0 {
-		return nil, errors.New("Error: need k<p. k: " + k.String() + ", p: " + p.String())
-	}
-	//generate the basePolynomial
-	var basePolynomial []*big.Int
-	basePolynomial = append(basePolynomial, k)
-	for i := 0; i < int(t.Int64())-1; i++ {
-		randPrime, err := rand.Prime(rand.Reader, bits/2)
-		if err != nil {
-			return result, err
-		}
-		basePolynomial = append(basePolynomial, randPrime)
-	}
-
-	//calculate shares, based on the basePolynomial
-	var shares []*big.Int
-	for i := 1; i < int(n.Int64())+1; i++ {
-		var pResultMod *big.Int
-		pResult := big.NewInt(int64(0))
-		for x, polElem := range basePolynomial {
-			if x == 0 {
-				pResult = pResult.Add(pResult, polElem)
-			} else {
-				iBigInt := big.NewInt(int64(i))
-				xBigInt := big.NewInt(int64(x))
-				iPowed := iBigInt.Exp(iBigInt, xBigInt, nil)
-				currElem := iPowed.Mul(iPowed, polElem)
-				pResult = pResult.Add(pResult, currElem)
-				pResultMod = pResult.Mod(pResult, p)
-			}
-		}
-		shares = append(shares, pResultMod)
-	}
-	//put the share together with his p value
-	result = packSharesAndI(shares)
-	return result, nil
-}
-
-func packSharesAndI(sharesString []*big.Int) (r [][]*big.Int) {
-	for i, share := range sharesString {
-		curr := []*big.Int{share, big.NewInt(int64(i + 1))}
-		r = append(r, curr)
-	}
-	return r
-}
-func unpackSharesAndI(sharesPacked [][]*big.Int) ([]*big.Int, []*big.Int) {
-	var shares []*big.Int
-	var i []*big.Int
-	for _, share := range sharesPacked {
-		shares = append(shares, share[0])
-		i = append(i, share[1])
-	}
-	return shares, i
-}
-
-// LagrangeInterpolation calculates the secret from given shares
-func LagrangeInterpolation(sharesGiven [][]*big.Int, p *big.Int) *big.Int {
-	resultN := big.NewInt(int64(0))
-	resultD := big.NewInt(int64(0))
-
-	//unpack shares
-	sharesBigInt, sharesIBigInt := unpackSharesAndI(sharesGiven)
-
-	for i := 0; i < len(sharesBigInt); i++ {
-		lagrangeNumerator := big.NewInt(int64(1))
-		lagrangeDenominator := big.NewInt(int64(1))
-		for j := 0; j < len(sharesBigInt); j++ {
-			if sharesIBigInt[i] != sharesIBigInt[j] {
-				currLagrangeNumerator := sharesIBigInt[j]
-				currLagrangeDenominator := new(big.Int).Sub(sharesIBigInt[j], sharesIBigInt[i])
-				lagrangeNumerator = new(big.Int).Mul(lagrangeNumerator, currLagrangeNumerator)
-				lagrangeDenominator = new(big.Int).Mul(lagrangeDenominator, currLagrangeDenominator)
-			}
-		}
-		numerator := new(big.Int).Mul(sharesBigInt[i], lagrangeNumerator)
-		quo := new(big.Int).Quo(numerator, lagrangeDenominator)
-		if quo.Int64() != 0 {
-			resultN = resultN.Add(resultN, quo)
-		} else {
-			resultNMULlagrangeDenominator := new(big.Int).Mul(resultN, lagrangeDenominator)
-			resultN = new(big.Int).Add(resultNMULlagrangeDenominator, numerator)
-
-			resultD = resultD.Add(resultD, lagrangeDenominator)
-		}
-	}
-
-	var modinvMul *big.Int
-	if resultD.Int64() != 0 {
-		modinv := new(big.Int).ModInverse(resultD, p)
-		modinvMul = new(big.Int).Mul(resultN, modinv)
-	} else {
-		modinvMul = resultN
-	}
-	r := new(big.Int).Mod(modinvMul, p)
-	return r
-}
diff --git a/shamirsecretsharing/shamirsecretsharing_test.go b/shamirsecretsharing/shamirsecretsharing_test.go
deleted file mode 100644
index b0e71c3..0000000
--- a/shamirsecretsharing/shamirsecretsharing_test.go
+++ /dev/null
@@ -1,44 +0,0 @@
-package shamirsecretsharing
-
-import (
-	"bytes"
-	"crypto/rand"
-	"math/big"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestCreate(t *testing.T) {
-	k := big.NewInt(int64(123456789))
-	p, err := rand.Prime(rand.Reader, bits/2)
-	assert.Nil(t, err)
-
-	nShares := big.NewInt(int64(6))
-	nNeededShares := big.NewInt(int64(3))
-	shares, err := Create(
-		nNeededShares,
-		nShares,
-		p,
-		k)
-	assert.Nil(t, err)
-
-	//generate sharesToUse
-	var sharesToUse [][]*big.Int
-	sharesToUse = append(sharesToUse, shares[2])
-	sharesToUse = append(sharesToUse, shares[1])
-	sharesToUse = append(sharesToUse, shares[0])
-	secr := LagrangeInterpolation(sharesToUse, p)
-
-	// fmt.Print("original secret: ")
-	// fmt.Println(k)
-	// fmt.Print("p: ")
-	// fmt.Println(p)
-	// fmt.Print("shares: ")
-	// fmt.Println(shares)
-	// fmt.Print("secret result: ")
-	// fmt.Println(secr)
-	if !bytes.Equal(k.Bytes(), secr.Bytes()) {
-		t.Errorf("reconstructed secret not correspond to original secret")
-	}
-}