mirror/gmsm
1
0
Fork 0
mirror of https://github.com/emmansun/gmsm.git synced 2025-04-26 04:06:18 +08:00
Code Issues Packages Projects Releases Wiki Activity

add comments

Browse Source
This commit is contained in:
Emman 2021-12-15 10:32:14 +08:00
parent b2713b5e0d
commit 0cd7f73183
1 changed files with 15 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sm2/sm2.go
View File

@ -1,5 +1,12 @@
package sm2 package sm2
// Further references:
// [NSA]: Suite B implementer's guide to FIPS 186-3
// http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.182.4503&rep=rep1&type=pdf
// [SECG]: SECG, SEC1
// http://www.secg.org/sec1-v2.pdf
//
import ( import (
"crypto" "crypto"
"crypto/aes" "crypto/aes"
@ -204,16 +211,16 @@ func P256() elliptic.Curve {
// curve using the procedure given in [NSA] A.2.1. // curve using the procedure given in [NSA] A.2.1.
func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error) { func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error) {
params := c.Params() params := c.Params()
b := make([]byte, params.BitSize/8+8) b := make([]byte, params.BitSize/8+8) // (N + 64) / 8 = （256 + 64） / 8
_, err = io.ReadFull(rand, b) _, err = io.ReadFull(rand, b)
if err != nil { if err != nil {
return return
} }
k = new(big.Int).SetBytes(b) k = new(big.Int).SetBytes(b) // 5.Convert returned_bits to the (non-negtive) integrer c
n := new(big.Int).Sub(params.N, one) n := new(big.Int).Sub(params.N, one)
k.Mod(k, n) k.Mod(k, n)
k.Add(k, one) k.Add(k, one) // 6. k = (c mod (n-1)) + 1, here n = params.N
return return
} }
@ -563,6 +570,7 @@ func fermatInverse(k, N *big.Int) *big.Int {
// private key's curve order, the hash will be truncated to that length. It // private key's curve order, the hash will be truncated to that length. It
// returns the signature as a pair of integers. The security of the private key // returns the signature as a pair of integers. The security of the private key
// depends on the entropy of rand. // depends on the entropy of rand.
// https://crypto.stackexchange.com/questions/60644/what-does-chopmd-refer-to-in-the-default-go-ecdsa-package
func Sign(rand io.Reader, priv *ecdsa.PrivateKey, hash []byte) (r, s *big.Int, err error) { func Sign(rand io.Reader, priv *ecdsa.PrivateKey, hash []byte) (r, s *big.Int, err error) {
if !strings.EqualFold(priv.Params().Name, P256().Params().Name) { if !strings.EqualFold(priv.Params().Name, P256().Params().Name) {
return ecdsa.Sign(rand, priv, hash) return ecdsa.Sign(rand, priv, hash)
@ -600,6 +608,10 @@ func Sign(rand io.Reader, priv *ecdsa.PrivateKey, hash []byte) (r, s *big.Int, e
// See [NSA] 3.4.1 // See [NSA] 3.4.1
c := priv.PublicKey.Curve c := priv.PublicKey.Curve
return signGeneric(priv, &csprng, c, hash)
}
func signGeneric(priv *ecdsa.PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve, hash []byte) (r, s *big.Int, err error) {
N := c.Params().N N := c.Params().N
if N.Sign() == 0 { if N.Sign() == 0 {
return nil, nil, errZeroParam return nil, nil, errZeroParam