Golang dsa.Sign函數代碼示例

func main() {
	var privateKey dsa.PrivateKey
	params := &privateKey.Parameters

	// L2048N224 is length of L and N
	if err := dsa.GenerateParameters(params, rand.Reader, dsa.L2048N224); err != nil {
		fmt.Printf("Err: %s", err)
		return
	}

	if err := dsa.GenerateKey(&privateKey, rand.Reader); err != nil {
		fmt.Printf("Err: %s", err)
		return
	}

	hashed := []byte("This is test hashed message")

	// It returns the signature as a pair of integers.
	r, s, err := dsa.Sign(rand.Reader, &privateKey, hashed)
	if err != nil {
		fmt.Printf("Err: %s", err)
		return
	}

	// Check signnature can be verified
	publicKey := &privateKey.PublicKey
	if dsa.Verify(publicKey, hashed, r, s) {
		fmt.Printf("Verified\n")
	}
}

func SignatureSign(hash []byte, priv *dsa.PrivateKey) (r, s []byte, err error) {
	ri, si, err := dsa.Sign(rand.Reader, priv, hash)
	if err != nil {
		return nil, nil, err
	}
	return []byte(base64.StdEncoding.EncodeToString(ri.Bytes())), []byte(base64.StdEncoding.EncodeToString(si.Bytes())), nil
}

// Sign signs a message with a private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey) (err os.Error) {
	sig.outSubpackets = sig.buildSubpackets()
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}

	switch priv.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		sig.RSASignature.bytes, err = rsa.SignPKCS1v15(rand.Reader, priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
	case PubKeyAlgoDSA:
		r, s, err := dsa.Sign(rand.Reader, priv.PrivateKey.(*dsa.PrivateKey), digest)
		if err == nil {
			sig.DSASigR.bytes = r.Bytes()
			sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes))
			sig.DSASigS.bytes = s.Bytes()
			sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes))
		}
	default:
		err = error.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}

// Sign signs a message with a private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
// If config is nil, sensible defaults will be used.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey, config *Config) (err error) {
	sig.outSubpackets = sig.buildSubpackets()
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}

	switch priv.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		sig.RSASignature.bytes, err = rsa.SignPKCS1v15(config.Random(), priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
	case PubKeyAlgoDSA:
		dsaPriv := priv.PrivateKey.(*dsa.PrivateKey)

		// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
		subgroupSize := (dsaPriv.Q.BitLen() + 7) / 8
		if len(digest) > subgroupSize {
			digest = digest[:subgroupSize]
		}
		r, s, err := dsa.Sign(config.Random(), dsaPriv, digest)
		if err == nil {
			sig.DSASigR.bytes = r.Bytes()
			sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes))
			sig.DSASigS.bytes = s.Bytes()
			sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes))
		}
	default:
		err = errors.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}

// SignDSA signs a message with a DSA private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
func (sig *Signature) SignDSA(h hash.Hash, priv *dsa.PrivateKey) (err os.Error) {
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}
	sig.DSASigR, sig.DSASigS, err = dsa.Sign(rand.Reader, priv, digest)
	return
}

func Sign() {
	key := Key()
	hash := HashMessage()
	r, s, err := dsa.Sign(rand.Reader, key, hash)
	if err != nil {
		log.Fatalf("failed to sign message: %s", err)
	}
	log.Printf("r: %v", r)
	log.Printf("s: %v", s)
}

func (p *DSAPrivateKey) Sign(hashed []byte, alg uint8) ([]byte, error) {
	r1, s1, err := dsa.Sign(rand.Reader, (*dsa.PrivateKey)(p), hashed)
	if err != nil {
		return nil, err
	}
	t := divRoundUp(divRoundUp(p.PublicKey.Y.BitLen(), 8)-64, 8)
	signature := []byte{byte(t)}
	signature = append(signature, intToBytes(r1, 20)...)
	signature = append(signature, intToBytes(s1, 20)...)
	return signature, nil
}

// Sign will generate a signature of a hashed data using dsa Sign.
func (priv *PrivateKey) Sign(rand io.Reader, hashed []byte) ([]byte, error) {
	r, s, err := dsa.Sign(rand, &priv.PrivateKey, hashed)
	if err == nil {
		rBytes := r.Bytes()
		sBytes := s.Bytes()

		out := make([]byte, 40)
		copy(out[20-len(rBytes):], rBytes)
		copy(out[len(out)-len(sBytes):], sBytes)
		return out, nil
	}
	return nil, err
}

// Sign signs a message with a private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
// If config is nil, sensible defaults will be used.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey, config *Config) (err error) {
	signer, hashIsSigner := h.(Signer)

	if !hashIsSigner && (priv == nil || priv.PrivateKey == nil) {
		err = errors.InvalidArgumentError("attempting to sign with nil PrivateKey")
		return
	}

	sig.outSubpackets = sig.buildSubpackets()
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}

	if hashIsSigner {
		err = signer.Sign(sig)
		return
	}

	switch priv.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		sig.RSASignature.bytes, err = rsa.SignPKCS1v15(config.Random(), priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
	case PubKeyAlgoDSA:
		dsaPriv := priv.PrivateKey.(*dsa.PrivateKey)

		// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
		subgroupSize := (dsaPriv.Q.BitLen() + 7) / 8
		if len(digest) > subgroupSize {
			digest = digest[:subgroupSize]
		}
		r, s, err := dsa.Sign(config.Random(), dsaPriv, digest)
		if err == nil {
			sig.DSASigR.bytes = r.Bytes()
			sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes))
			sig.DSASigS.bytes = s.Bytes()
			sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes))
		}
	case PubKeyAlgoECDSA:
		r, s, err := ecdsa.Sign(config.Random(), priv.PrivateKey.(*ecdsa.PrivateKey), digest)
		if err == nil {
			sig.ECDSASigR = FromBig(r)
			sig.ECDSASigS = FromBig(s)
		}
	default:
		err = errors.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}

func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) ([]byte, error) {
	h := crypto.SHA1.New()
	h.Write(data)
	digest := h.Sum(nil)
	r, s, err := dsa.Sign(rand, k.PrivateKey, digest)
	if err != nil {
		return nil, err
	}

	sig := make([]byte, 40)
	copy(sig[:20], r.Bytes())
	copy(sig[20:], s.Bytes())
	return sig, nil
}

func (ds *DSASigner) SignHash(h []byte) (sig []byte, err error) {
	var r, s *big.Int
	r, s, err = dsa.Sign(rand.Reader, ds.k, h)
	if err == nil {
		sig = make([]byte, 40)
		rb := r.Bytes()
		rl := len(rb)
		copy(sig[20-rl:20], rb)
		sb := s.Bytes()
		sl := len(sb)
		copy(sig[20+(20-sl):], sb)
	}
	return
}

func (dk *dsaKey) Sign(msg []byte) ([]byte, error) {
	h := sha1.New()
	h.Write(msg)
	r, s, err := dsa.Sign(rand.Reader, &dk.key, h.Sum(nil))
	if err != nil {
		return nil, err
	}
	sig := dsaSignature{r, s}
	b, err := asn1.Marshal(sig)
	if err != nil {
		return nil, err
	}
	return b, nil
}

// Sign signs a message with a private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
// If config is nil, sensible defaults will be used.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey, config *Config) (err error) {
	sig.outSubpackets = sig.buildSubpackets()
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}

	switch priv.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		// supports both *rsa.PrivateKey and crypto.Signer
		sig.RSASignature.bytes, err = priv.PrivateKey.(crypto.Signer).Sign(config.Random(), digest, sig.Hash)
		sig.RSASignature.bitLength = uint16(8 * len(sig.RSASignature.bytes))
	case PubKeyAlgoDSA:
		dsaPriv := priv.PrivateKey.(*dsa.PrivateKey)

		// Need to truncate hashBytes to match FIPS 186-3 section 4.6.
		subgroupSize := (dsaPriv.Q.BitLen() + 7) / 8
		if len(digest) > subgroupSize {
			digest = digest[:subgroupSize]
		}
		r, s, err := dsa.Sign(config.Random(), dsaPriv, digest)
		if err == nil {
			sig.DSASigR.bytes = r.Bytes()
			sig.DSASigR.bitLength = uint16(8 * len(sig.DSASigR.bytes))
			sig.DSASigS.bytes = s.Bytes()
			sig.DSASigS.bitLength = uint16(8 * len(sig.DSASigS.bytes))
		}
	case PubKeyAlgoECDSA:
		var r, s *big.Int
		if pk, ok := priv.PrivateKey.(*ecdsa.PrivateKey); ok {
			// direct support, avoid asn1 wrapping/unwrapping
			r, s, err = ecdsa.Sign(config.Random(), pk, digest)
		} else {
			var b []byte
			b, err = priv.PrivateKey.(crypto.Signer).Sign(config.Random(), digest, nil)
			if err == nil {
				r, s, err = unwrapECDSASig(b)
			}
		}
		if err == nil {
			sig.ECDSASigR = fromBig(r)
			sig.ECDSASigS = fromBig(s)
		}
	default:
		err = errors.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}

func (priv *PrivateKey) Sign(rand io.Reader, hashed []byte) []byte {
	r, s, err := dsa.Sign(rand, &priv.PrivateKey, hashed)
	if err != nil {
		panic(err.Error())
	}
	rBytes := r.Bytes()
	sBytes := s.Bytes()
	if len(rBytes) > dsaSubgroupBytes || len(sBytes) > dsaSubgroupBytes {
		panic("DSA signature too large")
	}

	out := make([]byte, 2*dsaSubgroupBytes)
	copy(out[dsaSubgroupBytes-len(rBytes):], rBytes)
	copy(out[len(out)-len(sBytes):], sBytes)
	return out
}

// Sign signs a message with a private key. The hash, h, must contain
// the hash of the message to be signed and will be mutated by this function.
// On success, the signature is stored in sig. Call Serialize to write it out.
func (sig *Signature) Sign(h hash.Hash, priv *PrivateKey) (err os.Error) {
	digest, err := sig.signPrepareHash(h)
	if err != nil {
		return
	}

	switch priv.PubKeyAlgo {
	case PubKeyAlgoRSA, PubKeyAlgoRSASignOnly:
		sig.RSASignature, err = rsa.SignPKCS1v15(rand.Reader, priv.PrivateKey.(*rsa.PrivateKey), sig.Hash, digest)
	case PubKeyAlgoDSA:
		sig.DSASigR, sig.DSASigS, err = dsa.Sign(rand.Reader, priv.PrivateKey.(*dsa.PrivateKey), digest)
	default:
		err = error.UnsupportedError("public key algorithm: " + strconv.Itoa(int(sig.PubKeyAlgo)))
	}

	return
}