shamir secret sharing: create secret sharing, and reconstruct secret from shares with Langrange Interpolation

rsa/rsa.go

@@ -12,24 +12,25 @@ const (
 
 var bigOne = big.NewInt(int64(1))
 
+// PublicKey stores the public key data
 type PublicKey struct {
 	E *big.Int `json:"e"`
 	N *big.Int `json:"n"`
 }
-type PublicKeyString struct {
-	E string `json:"e"`
-	N string `json:"n"`
-}
+
+// PrivateKey stores the private key data
 type PrivateKey struct {
 	D *big.Int `json:"d"`
 	N *big.Int `json:"n"`
 }
 
+// Key stores the public and private key data
 type Key struct {
 	PubK  PublicKey
 	PrivK PrivateKey
 }
 
+// GenerateKeyPair generates a random private and public key
 func GenerateKeyPair() (key Key, err error) {
 	p, err := rand.Prime(rand.Reader, bits/2)
 	if err != nil {
@@ -41,9 +42,9 @@ func GenerateKeyPair() (key Key, err error) {
 	}
 
 	n := new(big.Int).Mul(p, q)
-	p_1 := new(big.Int).Sub(p, bigOne)
-	q_1 := new(big.Int).Sub(q, bigOne)
-	phi := new(big.Int).Mul(p_1, q_1)
+	p1 := new(big.Int).Sub(p, bigOne)
+	q1 := new(big.Int).Sub(q, bigOne)
+	phi := new(big.Int).Mul(p1, q1)
 	e := 65537
 	var pubK PublicKey
 	pubK.E = big.NewInt(int64(e))
@@ -60,15 +61,19 @@ func GenerateKeyPair() (key Key, err error) {
 	return key, nil
 }
 
+// Encrypt encrypts a message m with given PublicKey
 func Encrypt(m *big.Int, pubK PublicKey) *big.Int {
 	c := new(big.Int).Exp(m, pubK.E, pubK.N)
 	return c
 }
+
+// Decrypt deencrypts a ciphertext c with given PrivateKey
 func Decrypt(c *big.Int, privK PrivateKey) *big.Int {
 	m := new(big.Int).Exp(c, privK.D, privK.N)
 	return m
 }
 
+// Blind blinds a message
 func Blind(m *big.Int, r *big.Int, pubK PublicKey) *big.Int {
 	rE := new(big.Int).Exp(r, pubK.E, nil)
 	mrE := new(big.Int).Mul(m, rE)
@@ -76,16 +81,21 @@ func Blind(m *big.Int, r *big.Int, pubK PublicKey) *big.Int {
 	return mBlinded
 }
 
+// BlindSign blind signs a message without knowing the content
 func BlindSign(m *big.Int, privK PrivateKey) *big.Int {
 	sigma := new(big.Int).Exp(m, privK.D, privK.N)
 	return sigma
 }
+
+// Unblind unblinds the Blinded Signature
 func Unblind(sigma *big.Int, r *big.Int, pubK PublicKey) *big.Int {
 	r1 := new(big.Int).ModInverse(r, pubK.N)
 	bsr := new(big.Int).Mul(sigma, r1)
 	sig := new(big.Int).Mod(bsr, pubK.N)
 	return sig
 }
+
+// Verify verifies the signature of a message given the PublicKey of the signer
 func Verify(msg *big.Int, mSigned *big.Int, pubK PublicKey) bool {
 	//decrypt the mSigned with pubK
 	Cd := new(big.Int).Exp(mSigned, pubK.E, nil)
@@ -93,6 +103,7 @@ func Verify(msg *big.Int, mSigned *big.Int, pubK PublicKey) bool {
 	return bytes.Equal(msg.Bytes(), m.Bytes())
 }
 
+// HomomorphicMul calculates the multiplication of tow encrypted values given a PublicKey
 func HomomorphicMul(c1 *big.Int, c2 *big.Int, pubK PublicKey) *big.Int {
 	c1c2 := new(big.Int).Mul(c1, c2)
 	n2 := new(big.Int).Mul(pubK.N, pubK.N)

rsa/rsa_test.go

@@ -2,7 +2,6 @@ package rsa
 
 import (
 	"bytes"
-	"fmt"
 	"math/big"
 	"testing"
 )
@@ -12,7 +11,6 @@ func TestEncryptDecrypt(t *testing.T) {
 	if err != nil {
 		t.Errorf(err.Error())
 	}
-	fmt.Println(key)
 	mBytes := []byte("Hi")
 	m := new(big.Int).SetBytes(mBytes)
 	c := Encrypt(m, key.PubK)