yaole
98 lines
2.6 KiB
Go
98 lines
2.6 KiB
Go
package outsource
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import (
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"crypto/rand"
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"errors"
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"io"
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"math/big"
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"xdx.jelly/xgcl/grand"
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"xdx.jelly/xgcl/he/paillier"
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"xdx.jelly/xgcl/sm/sm2"
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)
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// osBlindSignContext 外包服务盲协同签名上下文. 使用NewOSBlindSignContext生成.
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// 与盲签名外包服务端一致
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type OSBlindSignContext struct {
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OSSignContext
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}
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func NewOSBlindSignContext() *OSBlindSignContext {
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return new(OSBlindSignContext)
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}
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// 盲签名客户端(与JS一致)
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type clientBlindSignContext struct {
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pprivateKey *paillier.PrivateKey
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r *big.Int
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k1pp *big.Int
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rnd io.Reader
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}
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// NewClientBlindSignContext simple factory for creating clientBlindSignContext
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func NewClientBlindSignContext(pprivateKey *paillier.PrivateKey, rnd io.Reader) *clientBlindSignContext {
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ctx := &clientBlindSignContext{
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pprivateKey: pprivateKey,
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rnd: rnd,
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}
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if rnd == nil {
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ctx.rnd = grand.Reader
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}
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return ctx
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}
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// Step1 客户端签名第一步 收到外包服务返回的pp, 返回ecipher, p给虎符服务端
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//
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// pp是外包服务第一步返回的P'=k1p*G
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// 返回ecipher = Enc_paillier(e), p = k1p * k2pp * G
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func (c *clientBlindSignContext) Step1(e []byte, pp *sm2.PublicKey) (ecipher *paillier.Cipher, p *sm2.PublicKey, err error) {
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c.k1pp, err = rand.Int(c.rnd, sm2.OrderN())
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if err != nil {
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return nil, nil, err
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}
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x, y := sm2.Curve256.ScalarMult(pp.X, pp.Y, c.k1pp.Bytes())
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p = &sm2.PublicKey{Curve: sm2.Curve(), X: x, Y: y}
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ecipher, err = c.pprivateKey.Encrypt(new(big.Int).SetBytes(e), c.rnd)
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return ecipher, p, err
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}
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// Step2 客户端签名第二步, 收到虎符服务端盲签名接口ServerBlindSign返回的rcipher, s1, s2cipher, 计算s1p, 把s1p, s2p给外包服务
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func (c *clientBlindSignContext) Step2(rcipher *paillier.Cipher, s1 *big.Int, s2cipher *paillier.Cipher) (s1p *big.Int, s2p *big.Int, err error) {
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c.r, err = c.pprivateKey.Decrypt(rcipher)
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if err != nil {
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return nil, nil, err
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}
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c.r.Mod(c.r, sm2.OrderN())
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if c.r.Sign() == 0 {
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return nil, nil, errors.New("Outsource sign failed, r = 0")
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}
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s1p = c.k1pp
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c.k1pp = nil
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s1p.Mul(s1p, s1).Mod(s1p, sm2.OrderN())
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s2p, err = c.pprivateKey.Decrypt(s2cipher)
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s2p.Mod(s2p, sm2.OrderN())
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if err != nil {
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return nil, nil, err
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}
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return s1p, s2p, nil
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}
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// Step3 客户端签名第三步, 收到外包服务返回的w = Enc(s+r), 输出签名
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func (c *clientBlindSignContext) Step3(w *paillier.Cipher) (*sm2.Signature, error) {
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s, err := c.pprivateKey.Decrypt(w)
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if err != nil {
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return nil, err
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}
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if s.Sign() == 0 {
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return nil, errors.New("Outsource sign failed, s = 0")
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}
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s.Sub(s, c.r).Mod(s, sm2.OrderN())
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r := c.r
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c.r = nil
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return &sm2.Signature{R: r, S: s}, nil
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}
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