using glide

vendor/github.com/tjfoc/gmsm/sm2/cert_pool.go

@@ -0,0 +1,229 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"encoding/pem"
+	"errors"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"sync"
+)
+
+// Possible certificate files; stop after finding one.
+var certFiles = []string{
+	"/etc/ssl/certs/ca-certificates.crt",                // Debian/Ubuntu/Gentoo etc.
+	"/etc/pki/tls/certs/ca-bundle.crt",                  // Fedora/RHEL 6
+	"/etc/ssl/ca-bundle.pem",                            // OpenSUSE
+	"/etc/pki/tls/cacert.pem",                           // OpenELEC
+	"/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem", // CentOS/RHEL 7
+}
+
+// CertPool is a set of certificates.
+type CertPool struct {
+	bySubjectKeyId map[string][]int
+	byName         map[string][]int
+	certs          []*Certificate
+}
+
+// NewCertPool returns a new, empty CertPool.
+func NewCertPool() *CertPool {
+	return &CertPool{
+		bySubjectKeyId: make(map[string][]int),
+		byName:         make(map[string][]int),
+	}
+}
+
+// Possible directories with certificate files; stop after successfully
+// reading at least one file from a directory.
+var certDirectories = []string{
+	"/etc/ssl/certs",               // SLES10/SLES11, https://golang.org/issue/12139
+	"/system/etc/security/cacerts", // Android
+}
+
+var (
+	once           sync.Once
+	systemRoots    *CertPool
+	systemRootsErr error
+)
+
+func systemRootsPool() *CertPool {
+	once.Do(initSystemRoots)
+	return systemRoots
+}
+
+func initSystemRoots() {
+	systemRoots, systemRootsErr = loadSystemRoots()
+}
+
+func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	return nil, nil
+}
+
+func loadSystemRoots() (*CertPool, error) {
+	roots := NewCertPool()
+	var firstErr error
+	for _, file := range certFiles {
+		data, err := ioutil.ReadFile(file)
+		if err == nil {
+			roots.AppendCertsFromPEM(data)
+			return roots, nil
+		}
+		if firstErr == nil && !os.IsNotExist(err) {
+			firstErr = err
+		}
+	}
+
+	for _, directory := range certDirectories {
+		fis, err := ioutil.ReadDir(directory)
+		if err != nil {
+			if firstErr == nil && !os.IsNotExist(err) {
+				firstErr = err
+			}
+			continue
+		}
+		rootsAdded := false
+		for _, fi := range fis {
+			data, err := ioutil.ReadFile(directory + "/" + fi.Name())
+			if err == nil && roots.AppendCertsFromPEM(data) {
+				rootsAdded = true
+			}
+		}
+		if rootsAdded {
+			return roots, nil
+		}
+	}
+
+	return nil, firstErr
+}
+
+// SystemCertPool returns a copy of the system cert pool.
+//
+// Any mutations to the returned pool are not written to disk and do
+// not affect any other pool.
+func SystemCertPool() (*CertPool, error) {
+	if runtime.GOOS == "windows" {
+		// Issue 16736, 18609:
+		return nil, errors.New("crypto/x509: system root pool is not available on Windows")
+	}
+
+	return loadSystemRoots()
+}
+
+// findVerifiedParents attempts to find certificates in s which have signed the
+// given certificate. If any candidates were rejected then errCert will be set
+// to one of them, arbitrarily, and err will contain the reason that it was
+// rejected.
+func (s *CertPool) findVerifiedParents(cert *Certificate) (parents []int, errCert *Certificate, err error) {
+	if s == nil {
+		return
+	}
+	var candidates []int
+
+	if len(cert.AuthorityKeyId) > 0 {
+		candidates = s.bySubjectKeyId[string(cert.AuthorityKeyId)]
+	}
+	if len(candidates) == 0 {
+		candidates = s.byName[string(cert.RawIssuer)]
+	}
+
+	for _, c := range candidates {
+		if err = cert.CheckSignatureFrom(s.certs[c]); err == nil {
+			parents = append(parents, c)
+		} else {
+			errCert = s.certs[c]
+		}
+	}
+
+	return
+}
+
+func (s *CertPool) contains(cert *Certificate) bool {
+	if s == nil {
+		return false
+	}
+
+	candidates := s.byName[string(cert.RawSubject)]
+	for _, c := range candidates {
+		if s.certs[c].Equal(cert) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// AddCert adds a certificate to a pool.
+func (s *CertPool) AddCert(cert *Certificate) {
+	if cert == nil {
+		panic("adding nil Certificate to CertPool")
+	}
+
+	// Check that the certificate isn't being added twice.
+	if s.contains(cert) {
+		return
+	}
+
+	n := len(s.certs)
+	s.certs = append(s.certs, cert)
+
+	if len(cert.SubjectKeyId) > 0 {
+		keyId := string(cert.SubjectKeyId)
+		s.bySubjectKeyId[keyId] = append(s.bySubjectKeyId[keyId], n)
+	}
+	name := string(cert.RawSubject)
+	s.byName[name] = append(s.byName[name], n)
+}
+
+// AppendCertsFromPEM attempts to parse a series of PEM encoded certificates.
+// It appends any certificates found to s and reports whether any certificates
+// were successfully parsed.
+//
+// On many Linux systems, /etc/ssl/cert.pem will contain the system wide set
+// of root CAs in a format suitable for this function.
+func (s *CertPool) AppendCertsFromPEM(pemCerts []byte) (ok bool) {
+	for len(pemCerts) > 0 {
+		var block *pem.Block
+		block, pemCerts = pem.Decode(pemCerts)
+		if block == nil {
+			break
+		}
+		if block.Type != "CERTIFICATE" || len(block.Headers) != 0 {
+			continue
+		}
+
+		cert, err := ParseCertificate(block.Bytes)
+		if err != nil {
+			continue
+		}
+
+		s.AddCert(cert)
+		ok = true
+	}
+
+	return
+}
+
+// Subjects returns a list of the DER-encoded subjects of
+// all of the certificates in the pool.
+func (s *CertPool) Subjects() [][]byte {
+	res := make([][]byte, len(s.certs))
+	for i, c := range s.certs {
+		res[i] = c.RawSubject
+	}
+	return res
+}

vendor/github.com/tjfoc/gmsm/sm2/p256.go

@@ -0,0 +1,43 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"crypto/elliptic"
+	"math/big"
+	"sync"
+)
+
+var initonce sync.Once
+var p256Sm2Params *elliptic.CurveParams
+
+// 取自elliptic的p256.go文件，修改曲线参数为sm2
+// See FIPS 186-3, section D.2.3
+func initP256Sm2() {
+	p256Sm2Params = &elliptic.CurveParams{Name: "SM2-P-256"} // 注明为SM2
+	//SM2椭	椭 圆 曲 线 公 钥 密 码 算 法 推 荐 曲 线 参 数
+	p256Sm2Params.P, _ = new(big.Int).SetString("FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFF", 16)
+	p256Sm2Params.N, _ = new(big.Int).SetString("FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFF7203DF6B21C6052B53BBF40939D54123", 16)
+	p256Sm2Params.B, _ = new(big.Int).SetString("28E9FA9E9D9F5E344D5A9E4BCF6509A7F39789F515AB8F92DDBCBD414D940E93", 16)
+	p256Sm2Params.Gx, _ = new(big.Int).SetString("32C4AE2C1F1981195F9904466A39C9948FE30BBFF2660BE1715A4589334C74C7", 16)
+	p256Sm2Params.Gy, _ = new(big.Int).SetString("BC3736A2F4F6779C59BDCEE36B692153D0A9877CC62A474002DF32E52139F0A0", 16)
+	p256Sm2Params.BitSize = 256
+}
+
+func P256Sm2() elliptic.Curve {
+	initonce.Do(initP256Sm2)
+	return p256Sm2Params
+}

vendor/github.com/tjfoc/gmsm/sm2/pkcs1.go

@@ -0,0 +1,132 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"crypto/rsa"
+	"encoding/asn1"
+	"errors"
+	"math/big"
+)
+
+// pkcs1PrivateKey is a structure which mirrors the PKCS#1 ASN.1 for an RSA private key.
+type pkcs1PrivateKey struct {
+	Version int
+	N       *big.Int
+	E       int
+	D       *big.Int
+	P       *big.Int
+	Q       *big.Int
+	// We ignore these values, if present, because rsa will calculate them.
+	Dp   *big.Int `asn1:"optional"`
+	Dq   *big.Int `asn1:"optional"`
+	Qinv *big.Int `asn1:"optional"`
+
+	AdditionalPrimes []pkcs1AdditionalRSAPrime `asn1:"optional,omitempty"`
+}
+
+type pkcs1AdditionalRSAPrime struct {
+	Prime *big.Int
+
+	// We ignore these values because rsa will calculate them.
+	Exp   *big.Int
+	Coeff *big.Int
+}
+
+// ParsePKCS1PrivateKey returns an RSA private key from its ASN.1 PKCS#1 DER encoded form.
+func ParsePKCS1PrivateKey(der []byte) (*rsa.PrivateKey, error) {
+	var priv pkcs1PrivateKey
+	rest, err := asn1.Unmarshal(der, &priv)
+	if len(rest) > 0 {
+		return nil, asn1.SyntaxError{Msg: "trailing data"}
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if priv.Version > 1 {
+		return nil, errors.New("x509: unsupported private key version")
+	}
+
+	if priv.N.Sign() <= 0 || priv.D.Sign() <= 0 || priv.P.Sign() <= 0 || priv.Q.Sign() <= 0 {
+		return nil, errors.New("x509: private key contains zero or negative value")
+	}
+
+	key := new(rsa.PrivateKey)
+	key.PublicKey = rsa.PublicKey{
+		E: priv.E,
+		N: priv.N,
+	}
+
+	key.D = priv.D
+	key.Primes = make([]*big.Int, 2+len(priv.AdditionalPrimes))
+	key.Primes[0] = priv.P
+	key.Primes[1] = priv.Q
+	for i, a := range priv.AdditionalPrimes {
+		if a.Prime.Sign() <= 0 {
+			return nil, errors.New("x509: private key contains zero or negative prime")
+		}
+		key.Primes[i+2] = a.Prime
+		// We ignore the other two values because rsa will calculate
+		// them as needed.
+	}
+
+	err = key.Validate()
+	if err != nil {
+		return nil, err
+	}
+	key.Precompute()
+
+	return key, nil
+}
+
+// MarshalPKCS1PrivateKey converts a private key to ASN.1 DER encoded form.
+func MarshalPKCS1PrivateKey(key *rsa.PrivateKey) []byte {
+	key.Precompute()
+
+	version := 0
+	if len(key.Primes) > 2 {
+		version = 1
+	}
+
+	priv := pkcs1PrivateKey{
+		Version: version,
+		N:       key.N,
+		E:       key.PublicKey.E,
+		D:       key.D,
+		P:       key.Primes[0],
+		Q:       key.Primes[1],
+		Dp:      key.Precomputed.Dp,
+		Dq:      key.Precomputed.Dq,
+		Qinv:    key.Precomputed.Qinv,
+	}
+
+	priv.AdditionalPrimes = make([]pkcs1AdditionalRSAPrime, len(key.Precomputed.CRTValues))
+	for i, values := range key.Precomputed.CRTValues {
+		priv.AdditionalPrimes[i].Prime = key.Primes[2+i]
+		priv.AdditionalPrimes[i].Exp = values.Exp
+		priv.AdditionalPrimes[i].Coeff = values.Coeff
+	}
+
+	b, _ := asn1.Marshal(priv)
+	return b
+}
+
+// rsaPublicKey reflects the ASN.1 structure of a PKCS#1 public key.
+type rsaPublicKey struct {
+	N *big.Int
+	E int
+}

vendor/github.com/tjfoc/gmsm/sm2/pkcs8.go

@@ -0,0 +1,488 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/elliptic"
+	"crypto/hmac"
+	"crypto/md5"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/pem"
+	"errors"
+	"hash"
+	"io/ioutil"
+	"math/big"
+	"os"
+	"reflect"
+)
+
+/*
+ * reference to RFC5959 and RFC2898
+ */
+
+var (
+	oidPBES1  = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 3}  // pbeWithMD5AndDES-CBC(PBES1)
+	oidPBES2  = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 13} // id-PBES2(PBES2)
+	oidPBKDF2 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 12} // id-PBKDF2
+
+	oidKEYMD5    = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 5}
+	oidKEYSHA1   = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 7}
+	oidKEYSHA256 = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 9}
+	oidKEYSHA512 = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 11}
+
+	oidAES128CBC = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 2}
+	oidAES256CBC = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 42}
+
+	oidSM2 = asn1.ObjectIdentifier{1, 2, 840, 10045, 2, 1}
+)
+
+// reference to https://www.rfc-editor.org/rfc/rfc5958.txt
+type PrivateKeyInfo struct {
+	Version             int // v1 or v2
+	PrivateKeyAlgorithm []asn1.ObjectIdentifier
+	PrivateKey          []byte
+}
+
+// reference to https://www.rfc-editor.org/rfc/rfc5958.txt
+type EncryptedPrivateKeyInfo struct {
+	EncryptionAlgorithm Pbes2Algorithms
+	EncryptedData       []byte
+}
+
+// reference to https://www.ietf.org/rfc/rfc2898.txt
+type Pbes2Algorithms struct {
+	IdPBES2     asn1.ObjectIdentifier
+	Pbes2Params Pbes2Params
+}
+
+// reference to https://www.ietf.org/rfc/rfc2898.txt
+type Pbes2Params struct {
+	KeyDerivationFunc Pbes2KDfs // PBES2-KDFs
+	EncryptionScheme  Pbes2Encs // PBES2-Encs
+}
+
+// reference to https://www.ietf.org/rfc/rfc2898.txt
+type Pbes2KDfs struct {
+	IdPBKDF2    asn1.ObjectIdentifier
+	Pkdf2Params Pkdf2Params
+}
+
+type Pbes2Encs struct {
+	EncryAlgo asn1.ObjectIdentifier
+	IV        []byte
+}
+
+// reference to https://www.ietf.org/rfc/rfc2898.txt
+type Pkdf2Params struct {
+	Salt           []byte
+	IterationCount int
+	Prf            pkix.AlgorithmIdentifier
+}
+
+type sm2PrivateKey struct {
+	Version       int
+	PrivateKey    []byte
+	NamedCurveOID asn1.ObjectIdentifier `asn1:"optional,explicit,tag:0"`
+	PublicKey     asn1.BitString        `asn1:"optional,explicit,tag:1"`
+}
+
+type pkcs8 struct {
+	Version    int
+	Algo       pkix.AlgorithmIdentifier
+	PrivateKey []byte
+}
+
+// copy from crypto/pbkdf2.go
+func pbkdf(password, salt []byte, iter, keyLen int, h func() hash.Hash) []byte {
+	prf := hmac.New(h, password)
+	hashLen := prf.Size()
+	numBlocks := (keyLen + hashLen - 1) / hashLen
+
+	var buf [4]byte
+	dk := make([]byte, 0, numBlocks*hashLen)
+	U := make([]byte, hashLen)
+	for block := 1; block <= numBlocks; block++ {
+		// N.B.: || means concatenation, ^ means XOR
+		// for each block T_i = U_1 ^ U_2 ^ ... ^ U_iter
+		// U_1 = PRF(password, salt || uint(i))
+		prf.Reset()
+		prf.Write(salt)
+		buf[0] = byte(block >> 24)
+		buf[1] = byte(block >> 16)
+		buf[2] = byte(block >> 8)
+		buf[3] = byte(block)
+		prf.Write(buf[:4])
+		dk = prf.Sum(dk)
+		T := dk[len(dk)-hashLen:]
+		copy(U, T)
+
+		// U_n = PRF(password, U_(n-1))
+		for n := 2; n <= iter; n++ {
+			prf.Reset()
+			prf.Write(U)
+			U = U[:0]
+			U = prf.Sum(U)
+			for x := range U {
+				T[x] ^= U[x]
+			}
+		}
+	}
+	return dk[:keyLen]
+}
+
+func ParseSm2PublicKey(der []byte) (*PublicKey, error) {
+	var pubkey pkixPublicKey
+
+	if _, err := asn1.Unmarshal(der, &pubkey); err != nil {
+		return nil, err
+	}
+	if !reflect.DeepEqual(pubkey.Algo.Algorithm, oidSM2) {
+		return nil, errors.New("x509: not sm2 elliptic curve")
+	}
+	curve := P256Sm2()
+	x, y := elliptic.Unmarshal(curve, pubkey.BitString.Bytes)
+	pub := PublicKey{
+		Curve: curve,
+		X:     x,
+		Y:     y,
+	}
+	return &pub, nil
+}
+
+func MarshalSm2PublicKey(key *PublicKey) ([]byte, error) {
+	var r pkixPublicKey
+	var algo pkix.AlgorithmIdentifier
+
+	algo.Algorithm = oidSM2
+	algo.Parameters.Class = 0
+	algo.Parameters.Tag = 6
+	algo.Parameters.IsCompound = false
+	algo.Parameters.FullBytes = []byte{6, 8, 42, 129, 28, 207, 85, 1, 130, 45} // asn1.Marshal(asn1.ObjectIdentifier{1, 2, 156, 10197, 1, 301})
+	r.Algo = algo
+	r.BitString = asn1.BitString{Bytes: elliptic.Marshal(key.Curve, key.X, key.Y)}
+	return asn1.Marshal(r)
+}
+
+func ParseSm2PrivateKey(der []byte) (*PrivateKey, error) {
+	var privKey sm2PrivateKey
+
+	if _, err := asn1.Unmarshal(der, &privKey); err != nil {
+		return nil, errors.New("x509: failed to parse SM2 private key: " + err.Error())
+	}
+	curve := P256Sm2()
+	k := new(big.Int).SetBytes(privKey.PrivateKey)
+	curveOrder := curve.Params().N
+	if k.Cmp(curveOrder) >= 0 {
+		return nil, errors.New("x509: invalid elliptic curve private key value")
+	}
+	priv := new(PrivateKey)
+	priv.Curve = curve
+	priv.D = k
+	privateKey := make([]byte, (curveOrder.BitLen()+7)/8)
+	for len(privKey.PrivateKey) > len(privateKey) {
+		if privKey.PrivateKey[0] != 0 {
+			return nil, errors.New("x509: invalid private key length")
+		}
+		privKey.PrivateKey = privKey.PrivateKey[1:]
+	}
+	copy(privateKey[len(privateKey)-len(privKey.PrivateKey):], privKey.PrivateKey)
+	priv.X, priv.Y = curve.ScalarBaseMult(privateKey)
+	return priv, nil
+}
+
+func ParsePKCS8UnecryptedPrivateKey(der []byte) (*PrivateKey, error) {
+	var privKey pkcs8
+
+	if _, err := asn1.Unmarshal(der, &privKey); err != nil {
+		return nil, err
+	}
+	if !reflect.DeepEqual(privKey.Algo.Algorithm, oidSM2) {
+		return nil, errors.New("x509: not sm2 elliptic curve")
+	}
+	return ParseSm2PrivateKey(privKey.PrivateKey)
+}
+
+func ParsePKCS8EcryptedPrivateKey(der, pwd []byte) (*PrivateKey, error) {
+	var keyInfo EncryptedPrivateKeyInfo
+
+	_, err := asn1.Unmarshal(der, &keyInfo)
+	if err != nil {
+		return nil, errors.New("x509: unknown format")
+	}
+	if !reflect.DeepEqual(keyInfo.EncryptionAlgorithm.IdPBES2, oidPBES2) {
+		return nil, errors.New("x509: only support PBES2")
+	}
+	encryptionScheme := keyInfo.EncryptionAlgorithm.Pbes2Params.EncryptionScheme
+	keyDerivationFunc := keyInfo.EncryptionAlgorithm.Pbes2Params.KeyDerivationFunc
+	if !reflect.DeepEqual(keyDerivationFunc.IdPBKDF2, oidPBKDF2) {
+		return nil, errors.New("x509: only support PBKDF2")
+	}
+	pkdf2Params := keyDerivationFunc.Pkdf2Params
+	if !reflect.DeepEqual(encryptionScheme.EncryAlgo, oidAES128CBC) &&
+		!reflect.DeepEqual(encryptionScheme.EncryAlgo, oidAES256CBC) {
+		return nil, errors.New("x509: unknow encryption algorithm")
+	}
+	iv := encryptionScheme.IV
+	salt := pkdf2Params.Salt
+	iter := pkdf2Params.IterationCount
+	encryptedKey := keyInfo.EncryptedData
+	var key []byte
+	switch {
+	case pkdf2Params.Prf.Algorithm.Equal(oidKEYMD5):
+		key = pbkdf(pwd, salt, iter, 32, md5.New)
+		break
+	case pkdf2Params.Prf.Algorithm.Equal(oidKEYSHA1):
+		key = pbkdf(pwd, salt, iter, 32, sha1.New)
+		break
+	case pkdf2Params.Prf.Algorithm.Equal(oidKEYSHA256):
+		key = pbkdf(pwd, salt, iter, 32, sha256.New)
+		break
+	case pkdf2Params.Prf.Algorithm.Equal(oidKEYSHA512):
+		key = pbkdf(pwd, salt, iter, 32, sha512.New)
+		break
+	default:
+		return nil, errors.New("x509: unknown hash algorithm")
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	mode := cipher.NewCBCDecrypter(block, iv)
+	mode.CryptBlocks(encryptedKey, encryptedKey)
+	rKey, err := ParsePKCS8UnecryptedPrivateKey(encryptedKey)
+	if err != nil {
+		return nil, errors.New("pkcs8: incorrect password")
+	}
+	return rKey, nil
+}
+
+func ParsePKCS8PrivateKey(der, pwd []byte) (*PrivateKey, error) {
+	if pwd == nil {
+		return ParsePKCS8UnecryptedPrivateKey(der)
+	}
+	return ParsePKCS8EcryptedPrivateKey(der, pwd)
+}
+
+func MarshalSm2UnecryptedPrivateKey(key *PrivateKey) ([]byte, error) {
+	var r pkcs8
+	var priv sm2PrivateKey
+	var algo pkix.AlgorithmIdentifier
+
+	algo.Algorithm = oidSM2
+	algo.Parameters.Class = 0
+	algo.Parameters.Tag = 6
+	algo.Parameters.IsCompound = false
+	algo.Parameters.FullBytes = []byte{6, 8, 42, 129, 28, 207, 85, 1, 130, 45} // asn1.Marshal(asn1.ObjectIdentifier{1, 2, 156, 10197, 1, 301})
+	priv.Version = 1
+	priv.NamedCurveOID = oidNamedCurveP256SM2
+	priv.PublicKey = asn1.BitString{Bytes: elliptic.Marshal(key.Curve, key.X, key.Y)}
+	priv.PrivateKey = key.D.Bytes()
+	r.Version = 0
+	r.Algo = algo
+	r.PrivateKey, _ = asn1.Marshal(priv)
+	return asn1.Marshal(r)
+}
+
+func MarshalSm2EcryptedPrivateKey(PrivKey *PrivateKey, pwd []byte) ([]byte, error) {
+	der, err := MarshalSm2UnecryptedPrivateKey(PrivKey)
+	if err != nil {
+		return nil, err
+	}
+	iter := 2048
+	salt := make([]byte, 8)
+	iv := make([]byte, 16)
+	rand.Reader.Read(salt)
+	rand.Reader.Read(iv)
+	key := pbkdf(pwd, salt, iter, 32, sha1.New) // 默认是SHA1
+	padding := aes.BlockSize - len(der)%aes.BlockSize
+	if padding > 0 {
+		n := len(der)
+		der = append(der, make([]byte, padding)...)
+		for i := 0; i < padding; i++ {
+			der[n+i] = byte(padding)
+		}
+	}
+	encryptedKey := make([]byte, len(der))
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	mode := cipher.NewCBCEncrypter(block, iv)
+	mode.CryptBlocks(encryptedKey, der)
+	var algorithmIdentifier pkix.AlgorithmIdentifier
+	algorithmIdentifier.Algorithm = oidKEYSHA1
+	algorithmIdentifier.Parameters.Tag = 5
+	algorithmIdentifier.Parameters.IsCompound = false
+	algorithmIdentifier.Parameters.FullBytes = []byte{5, 0}
+	keyDerivationFunc := Pbes2KDfs{
+		oidPBKDF2,
+		Pkdf2Params{
+			salt,
+			iter,
+			algorithmIdentifier,
+		},
+	}
+	encryptionScheme := Pbes2Encs{
+		oidAES256CBC,
+		iv,
+	}
+	pbes2Algorithms := Pbes2Algorithms{
+		oidPBES2,
+		Pbes2Params{
+			keyDerivationFunc,
+			encryptionScheme,
+		},
+	}
+	encryptedPkey := EncryptedPrivateKeyInfo{
+		pbes2Algorithms,
+		encryptedKey,
+	}
+	return asn1.Marshal(encryptedPkey)
+}
+
+func MarshalSm2PrivateKey(key *PrivateKey, pwd []byte) ([]byte, error) {
+	if pwd == nil {
+		return MarshalSm2UnecryptedPrivateKey(key)
+	}
+	return MarshalSm2EcryptedPrivateKey(key, pwd)
+}
+
+func ReadPrivateKeyFromMem(data []byte, pwd []byte) (*PrivateKey, error) {
+	var block *pem.Block
+
+	block, _ = pem.Decode(data)
+	if block == nil {
+		return nil, errors.New("failed to decode private key")
+	}
+	priv, err := ParsePKCS8PrivateKey(block.Bytes, pwd)
+	return priv, err
+}
+
+func ReadPrivateKeyFromPem(FileName string, pwd []byte) (*PrivateKey, error) {
+	data, err := ioutil.ReadFile(FileName)
+	if err != nil {
+		return nil, err
+	}
+	return ReadPrivateKeyFromMem(data, pwd)
+}
+
+func WritePrivateKeytoMem(key *PrivateKey, pwd []byte) ([]byte, error) {
+	var block *pem.Block
+
+	der, err := MarshalSm2PrivateKey(key, pwd)
+	if err != nil {
+		return nil, err
+	}
+	if pwd != nil {
+		block = &pem.Block{
+			Type:  "ENCRYPTED PRIVATE KEY",
+			Bytes: der,
+		}
+	} else {
+		block = &pem.Block{
+			Type:  "PRIVATE KEY",
+			Bytes: der,
+		}
+	}
+	return pem.EncodeToMemory(block), nil
+}
+
+func WritePrivateKeytoPem(FileName string, key *PrivateKey, pwd []byte) (bool, error) {
+	var block *pem.Block
+
+	der, err := MarshalSm2PrivateKey(key, pwd)
+	if err != nil {
+		return false, err
+	}
+	if pwd != nil {
+		block = &pem.Block{
+			Type:  "ENCRYPTED PRIVATE KEY",
+			Bytes: der,
+		}
+	} else {
+		block = &pem.Block{
+			Type:  "PRIVATE KEY",
+			Bytes: der,
+		}
+	}
+	file, err := os.Create(FileName)
+	if err != nil {
+		return false, err
+	}
+	defer file.Close()
+	err = pem.Encode(file, block)
+	if err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+func ReadPublicKeyFromMem(data []byte, _ []byte) (*PublicKey, error) {
+	block, _ := pem.Decode(data)
+	if block == nil || block.Type != "PUBLIC KEY" {
+		return nil, errors.New("failed to decode public key")
+	}
+	pub, err := ParseSm2PublicKey(block.Bytes)
+	return pub, err
+}
+
+func ReadPublicKeyFromPem(FileName string, pwd []byte) (*PublicKey, error) {
+	data, err := ioutil.ReadFile(FileName)
+	if err != nil {
+		return nil, err
+	}
+	return ReadPublicKeyFromMem(data, pwd)
+}
+
+func WritePublicKeytoMem(key *PublicKey, _ []byte) ([]byte, error) {
+	der, err := MarshalSm2PublicKey(key)
+	if err != nil {
+		return nil, err
+	}
+	block := &pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: der,
+	}
+	return pem.EncodeToMemory(block), nil
+}
+
+func WritePublicKeytoPem(FileName string, key *PublicKey, _ []byte) (bool, error) {
+	der, err := MarshalSm2PublicKey(key)
+	if err != nil {
+		return false, err
+	}
+	block := &pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: der,
+	}
+	file, err := os.Create(FileName)
+	defer file.Close()
+	if err != nil {
+		return false, err
+	}
+	err = pem.Encode(file, block)
+	if err != nil {
+		return false, err
+	}
+	return true, nil
+}

vendor/github.com/tjfoc/gmsm/sm2/sm2.go

@@ -0,0 +1,222 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+// reference to ecdsa
+import (
+	"crypto"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/sha512"
+	"encoding/asn1"
+	"errors"
+	"io"
+	"math/big"
+)
+
+type combinedMult interface {
+	CombinedMult(bigX, bigY *big.Int, baseScalar, scalar []byte) (x, y *big.Int)
+}
+
+const (
+	aesIV = "IV for <SM2> CTR"
+)
+
+type PublicKey struct {
+	elliptic.Curve
+	X, Y *big.Int
+}
+
+type PrivateKey struct {
+	PublicKey
+	D *big.Int
+}
+
+type sm2Signature struct {
+	R, S *big.Int
+}
+
+// The SM2's private key contains the public key
+func (priv *PrivateKey) Public() crypto.PublicKey {
+	return &priv.PublicKey
+}
+
+// sign format = 30 + len(z) + 02 + len(r) + r + 02 + len(s) + s, z being what follows its size, ie 02+len(r)+r+02+len(s)+s
+func (priv *PrivateKey) Sign(rand io.Reader, msg []byte, opts crypto.SignerOpts) ([]byte, error) {
+	r, s, err := Sign(priv, msg)
+	if err != nil {
+		return nil, err
+	}
+	return asn1.Marshal(sm2Signature{r, s})
+}
+
+func (pub *PublicKey) Verify(msg []byte, sign []byte) bool {
+	var sm2Sign sm2Signature
+	_, err := asn1.Unmarshal(sign, &sm2Sign)
+	if err != nil {
+		return false
+	}
+	return Verify(pub, msg, sm2Sign.R, sm2Sign.S)
+}
+
+var one = new(big.Int).SetInt64(1)
+
+func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error) {
+	params := c.Params()
+	b := make([]byte, params.BitSize/8+8)
+	_, err = io.ReadFull(rand, b)
+	if err != nil {
+		return
+	}
+	k = new(big.Int).SetBytes(b)
+	n := new(big.Int).Sub(params.N, one)
+	k.Mod(k, n)
+	k.Add(k, one)
+	return
+}
+
+func GenerateKey() (*PrivateKey, error) {
+	c := P256Sm2()
+	k, err := randFieldElement(c, rand.Reader)
+	if err != nil {
+		return nil, err
+	}
+	priv := new(PrivateKey)
+	priv.PublicKey.Curve = c
+	priv.D = k
+	priv.PublicKey.X, priv.PublicKey.Y = c.ScalarBaseMult(k.Bytes())
+	return priv, nil
+}
+
+var errZeroParam = errors.New("zero parameter")
+
+func Sign(priv *PrivateKey, hash []byte) (r, s *big.Int, err error) {
+	entropylen := (priv.Curve.Params().BitSize + 7) / 16
+	if entropylen > 32 {
+		entropylen = 32
+	}
+	entropy := make([]byte, entropylen)
+	_, err = io.ReadFull(rand.Reader, entropy)
+	if err != nil {
+		return
+	}
+
+	// Initialize an SHA-512 hash context; digest ...
+	md := sha512.New()
+	md.Write(priv.D.Bytes()) // the private key,
+	md.Write(entropy)        // the entropy,
+	md.Write(hash)           // and the input hash;
+	key := md.Sum(nil)[:32]  // and compute ChopMD-256(SHA-512),
+	// which is an indifferentiable MAC.
+
+	// Create an AES-CTR instance to use as a CSPRNG.
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Create a CSPRNG that xors a stream of zeros with
+	// the output of the AES-CTR instance.
+	csprng := cipher.StreamReader{
+		R: zeroReader,
+		S: cipher.NewCTR(block, []byte(aesIV)),
+	}
+
+	// See [NSA] 3.4.1
+	c := priv.PublicKey.Curve
+	N := c.Params().N
+	if N.Sign() == 0 {
+		return nil, nil, errZeroParam
+	}
+	var k *big.Int
+	e := new(big.Int).SetBytes(hash)
+	for { // 调整算法细节以实现SM2
+		for {
+			k, err = randFieldElement(c, csprng)
+			if err != nil {
+				r = nil
+				return
+			}
+			r, _ = priv.Curve.ScalarBaseMult(k.Bytes())
+			r.Add(r, e)
+			r.Mod(r, N)
+			if r.Sign() != 0 {
+				break
+			}
+			if t := new(big.Int).Add(r, k); t.Cmp(N) == 0 {
+				break
+			}
+		}
+		rD := new(big.Int).Mul(priv.D, r)
+		s = new(big.Int).Sub(k, rD)
+		d1 := new(big.Int).Add(priv.D, one)
+		d1Inv := new(big.Int).ModInverse(d1, N)
+		s.Mul(s, d1Inv)
+		s.Mod(s, N)
+		if s.Sign() != 0 {
+			break
+		}
+	}
+	return
+}
+
+func Verify(pub *PublicKey, hash []byte, r, s *big.Int) bool {
+	c := pub.Curve
+	N := c.Params().N
+
+	if r.Sign() <= 0 || s.Sign() <= 0 {
+		return false
+	}
+	if r.Cmp(N) >= 0 || s.Cmp(N) >= 0 {
+		return false
+	}
+
+	// 调整算法细节以实现SM2
+	t := new(big.Int).Add(r, s)
+	t.Mod(t, N)
+	if N.Sign() == 0 {
+		return false
+	}
+
+	var x *big.Int
+	if opt, ok := c.(combinedMult); ok {
+		x, _ = opt.CombinedMult(pub.X, pub.Y, s.Bytes(), t.Bytes())
+	} else {
+		x1, y1 := c.ScalarBaseMult(s.Bytes())
+		x2, y2 := c.ScalarMult(pub.X, pub.Y, t.Bytes())
+		x, _ = c.Add(x1, y1, x2, y2)
+	}
+
+	e := new(big.Int).SetBytes(hash)
+	x.Add(x, e)
+	x.Mod(x, N)
+	return x.Cmp(r) == 0
+}
+
+type zr struct {
+	io.Reader
+}
+
+func (z *zr) Read(dst []byte) (n int, err error) {
+	for i := range dst {
+		dst[i] = 0
+	}
+	return len(dst), nil
+}
+
+var zeroReader = &zr{}

vendor/github.com/tjfoc/gmsm/sm2/sm2_test.go

@@ -0,0 +1,184 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+                 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"crypto/rand"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"math/big"
+	"net"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestSm2(t *testing.T) {
+	priv, err := GenerateKey() // 生成密钥对
+	if err != nil {
+		log.Fatal(err)
+	}
+	ok, err := WritePrivateKeytoPem("priv.pem", priv, nil) // 生成密钥文件
+	if ok != true {
+		log.Fatal(err)
+	}
+	pubKey, _ := priv.Public().(*PublicKey)
+	ok, err = WritePublicKeytoPem("pub.pem", pubKey, nil) // 生成公钥文件
+	if ok != true {
+		log.Fatal(err)
+	}
+	msg := []byte("test")
+	err = ioutil.WriteFile("ifile", msg, os.FileMode(0644)) // 生成测试文件
+	if err != nil {
+		log.Fatal(err)
+	}
+	privKey, err := ReadPrivateKeyFromPem("priv.pem", nil) // 读取密钥
+	if err != nil {
+		log.Fatal(err)
+	}
+	pubKey, err = ReadPublicKeyFromPem("pub.pem", nil) // 读取公钥
+	if err != nil {
+		log.Fatal(err)
+	}
+	msg, _ = ioutil.ReadFile("ifile")                // 从文件读取数据
+	sign, err := privKey.Sign(rand.Reader, msg, nil) // 签名
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = ioutil.WriteFile("ofile", sign, os.FileMode(0644))
+	if err != nil {
+		log.Fatal(err)
+	}
+	signdata, _ := ioutil.ReadFile("ofile")
+	ok = privKey.Verify(msg, signdata) // 密钥验证
+	if ok != true {
+		fmt.Printf("Verify error\n")
+	} else {
+		fmt.Printf("Verify ok\n")
+	}
+	ok = pubKey.Verify(msg, signdata) // 公钥验证
+	if ok != true {
+		fmt.Printf("Verify error\n")
+	} else {
+		fmt.Printf("Verify ok\n")
+	}
+	templateReq := CertificateRequest{
+		Subject: pkix.Name{
+			CommonName:   "test.example.com",
+			Organization: []string{"Test"},
+		},
+		//		SignatureAlgorithm: ECDSAWithSHA256,
+		SignatureAlgorithm: SM2WithSM3,
+	}
+	_, err = CreateCertificateRequestToPem("req.pem", &templateReq, privKey)
+	if err != nil {
+		log.Fatal(err)
+	}
+	req, err := ReadCertificateRequestFromPem("req.pem")
+	if err != nil {
+		log.Fatal(err)
+	}
+	err = req.CheckSignature()
+	if err != nil {
+		log.Fatal(err)
+	} else {
+		fmt.Printf("CheckSignature ok\n")
+	}
+	testExtKeyUsage := []ExtKeyUsage{ExtKeyUsageClientAuth, ExtKeyUsageServerAuth}
+	testUnknownExtKeyUsage := []asn1.ObjectIdentifier{[]int{1, 2, 3}, []int{2, 59, 1}}
+	extraExtensionData := []byte("extra extension")
+	commonName := "test.example.com"
+	template := Certificate{
+		// SerialNumber is negative to ensure that negative
+		// values are parsed. This is due to the prevalence of
+		// buggy code that produces certificates with negative
+		// serial numbers.
+		SerialNumber: big.NewInt(-1),
+		Subject: pkix.Name{
+			CommonName:   commonName,
+			Organization: []string{"TEST"},
+			Country:      []string{"China"},
+			ExtraNames: []pkix.AttributeTypeAndValue{
+				{
+					Type:  []int{2, 5, 4, 42},
+					Value: "Gopher",
+				},
+				// This should override the Country, above.
+				{
+					Type:  []int{2, 5, 4, 6},
+					Value: "NL",
+				},
+			},
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		//		SignatureAlgorithm: ECDSAWithSHA256,
+		SignatureAlgorithm: SM2WithSM3,
+
+		SubjectKeyId: []byte{1, 2, 3, 4},
+		KeyUsage:     KeyUsageCertSign,
+
+		ExtKeyUsage:        testExtKeyUsage,
+		UnknownExtKeyUsage: testUnknownExtKeyUsage,
+
+		BasicConstraintsValid: true,
+		IsCA: true,
+
+		OCSPServer:            []string{"http://ocsp.example.com"},
+		IssuingCertificateURL: []string{"http://crt.example.com/ca1.crt"},
+
+		DNSNames:       []string{"test.example.com"},
+		EmailAddresses: []string{"gopher@golang.org"},
+		IPAddresses:    []net.IP{net.IPv4(127, 0, 0, 1).To4(), net.ParseIP("2001:4860:0:2001::68")},
+
+		PolicyIdentifiers:   []asn1.ObjectIdentifier{[]int{1, 2, 3}},
+		PermittedDNSDomains: []string{".example.com", "example.com"},
+
+		CRLDistributionPoints: []string{"http://crl1.example.com/ca1.crl", "http://crl2.example.com/ca1.crl"},
+
+		ExtraExtensions: []pkix.Extension{
+			{
+				Id:    []int{1, 2, 3, 4},
+				Value: extraExtensionData,
+			},
+			// This extension should override the SubjectKeyId, above.
+			{
+				Id:       oidExtensionSubjectKeyId,
+				Critical: false,
+				Value:    []byte{0x04, 0x04, 4, 3, 2, 1},
+			},
+		},
+	}
+	pubKey, _ = priv.Public().(*PublicKey)
+	ok, _ = CreateCertificateToPem("cert.pem", &template, &template, pubKey, privKey)
+	if ok != true {
+		fmt.Printf("failed to create cert file\n")
+	}
+	cert, err := ReadCertificateFromPem("cert.pem")
+	if err != nil {
+		fmt.Printf("failed to read cert file")
+	}
+	err = cert.CheckSignature(cert.SignatureAlgorithm, cert.RawTBSCertificate, cert.Signature)
+	if err != nil {
+		log.Fatal(err)
+	} else {
+		fmt.Printf("CheckSignature ok\n")
+	}
+}

vendor/github.com/tjfoc/gmsm/sm2/verify.go

@@ -0,0 +1,568 @@
+/*
+Copyright Suzhou Tongji Fintech Research Institute 2017 All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sm2
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"net"
+	"runtime"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+type InvalidReason int
+
+const (
+	// NotAuthorizedToSign results when a certificate is signed by another
+	// which isn't marked as a CA certificate.
+	NotAuthorizedToSign InvalidReason = iota
+	// Expired results when a certificate has expired, based on the time
+	// given in the VerifyOptions.
+	Expired
+	// CANotAuthorizedForThisName results when an intermediate or root
+	// certificate has a name constraint which doesn't include the name
+	// being checked.
+	CANotAuthorizedForThisName
+	// TooManyIntermediates results when a path length constraint is
+	// violated.
+	TooManyIntermediates
+	// IncompatibleUsage results when the certificate's key usage indicates
+	// that it may only be used for a different purpose.
+	IncompatibleUsage
+	// NameMismatch results when the subject name of a parent certificate
+	// does not match the issuer name in the child.
+	NameMismatch
+)
+
+// CertificateInvalidError results when an odd error occurs. Users of this
+// library probably want to handle all these errors uniformly.
+type CertificateInvalidError struct {
+	Cert   *Certificate
+	Reason InvalidReason
+}
+
+func (e CertificateInvalidError) Error() string {
+	switch e.Reason {
+	case NotAuthorizedToSign:
+		return "x509: certificate is not authorized to sign other certificates"
+	case Expired:
+		return "x509: certificate has expired or is not yet valid"
+	case CANotAuthorizedForThisName:
+		return "x509: a root or intermediate certificate is not authorized to sign in this domain"
+	case TooManyIntermediates:
+		return "x509: too many intermediates for path length constraint"
+	case IncompatibleUsage:
+		return "x509: certificate specifies an incompatible key usage"
+	case NameMismatch:
+		return "x509: issuer name does not match subject from issuing certificate"
+	}
+	return "x509: unknown error"
+}
+
+// HostnameError results when the set of authorized names doesn't match the
+// requested name.
+type HostnameError struct {
+	Certificate *Certificate
+	Host        string
+}
+
+func (h HostnameError) Error() string {
+	c := h.Certificate
+
+	var valid string
+	if ip := net.ParseIP(h.Host); ip != nil {
+		// Trying to validate an IP
+		if len(c.IPAddresses) == 0 {
+			return "x509: cannot validate certificate for " + h.Host + " because it doesn't contain any IP SANs"
+		}
+		for _, san := range c.IPAddresses {
+			if len(valid) > 0 {
+				valid += ", "
+			}
+			valid += san.String()
+		}
+	} else {
+		if len(c.DNSNames) > 0 {
+			valid = strings.Join(c.DNSNames, ", ")
+		} else {
+			valid = c.Subject.CommonName
+		}
+	}
+
+	if len(valid) == 0 {
+		return "x509: certificate is not valid for any names, but wanted to match " + h.Host
+	}
+	return "x509: certificate is valid for " + valid + ", not " + h.Host
+}
+
+// UnknownAuthorityError results when the certificate issuer is unknown
+type UnknownAuthorityError struct {
+	Cert *Certificate
+	// hintErr contains an error that may be helpful in determining why an
+	// authority wasn't found.
+	hintErr error
+	// hintCert contains a possible authority certificate that was rejected
+	// because of the error in hintErr.
+	hintCert *Certificate
+}
+
+func (e UnknownAuthorityError) Error() string {
+	s := "x509: certificate signed by unknown authority"
+	if e.hintErr != nil {
+		certName := e.hintCert.Subject.CommonName
+		if len(certName) == 0 {
+			if len(e.hintCert.Subject.Organization) > 0 {
+				certName = e.hintCert.Subject.Organization[0]
+			} else {
+				certName = "serial:" + e.hintCert.SerialNumber.String()
+			}
+		}
+		s += fmt.Sprintf(" (possibly because of %q while trying to verify candidate authority certificate %q)", e.hintErr, certName)
+	}
+	return s
+}
+
+// SystemRootsError results when we fail to load the system root certificates.
+type SystemRootsError struct {
+	Err error
+}
+
+func (se SystemRootsError) Error() string {
+	msg := "x509: failed to load system roots and no roots provided"
+	if se.Err != nil {
+		return msg + "; " + se.Err.Error()
+	}
+	return msg
+}
+
+// errNotParsed is returned when a certificate without ASN.1 contents is
+// verified. Platform-specific verification needs the ASN.1 contents.
+var errNotParsed = errors.New("x509: missing ASN.1 contents; use ParseCertificate")
+
+// VerifyOptions contains parameters for Certificate.Verify. It's a structure
+// because other PKIX verification APIs have ended up needing many options.
+type VerifyOptions struct {
+	DNSName       string
+	Intermediates *CertPool
+	Roots         *CertPool // if nil, the system roots are used
+	CurrentTime   time.Time // if zero, the current time is used
+	// KeyUsage specifies which Extended Key Usage values are acceptable.
+	// An empty list means ExtKeyUsageServerAuth. Key usage is considered a
+	// constraint down the chain which mirrors Windows CryptoAPI behavior,
+	// but not the spec. To accept any key usage, include ExtKeyUsageAny.
+	KeyUsages []ExtKeyUsage
+}
+
+const (
+	leafCertificate = iota
+	intermediateCertificate
+	rootCertificate
+)
+
+func matchNameConstraint(domain, constraint string) bool {
+	// The meaning of zero length constraints is not specified, but this
+	// code follows NSS and accepts them as valid for everything.
+	if len(constraint) == 0 {
+		return true
+	}
+
+	if len(domain) < len(constraint) {
+		return false
+	}
+
+	prefixLen := len(domain) - len(constraint)
+	if !strings.EqualFold(domain[prefixLen:], constraint) {
+		return false
+	}
+
+	if prefixLen == 0 {
+		return true
+	}
+
+	isSubdomain := domain[prefixLen-1] == '.'
+	constraintHasLeadingDot := constraint[0] == '.'
+	return isSubdomain != constraintHasLeadingDot
+}
+
+// isValid performs validity checks on the c.
+func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *VerifyOptions) error {
+	if len(currentChain) > 0 {
+		child := currentChain[len(currentChain)-1]
+		if !bytes.Equal(child.RawIssuer, c.RawSubject) {
+			return CertificateInvalidError{c, NameMismatch}
+		}
+	}
+	now := opts.CurrentTime
+	if now.IsZero() {
+		now = time.Now()
+	}
+	if now.Before(c.NotBefore) || now.After(c.NotAfter) {
+		return CertificateInvalidError{c, Expired}
+	}
+	if len(c.PermittedDNSDomains) > 0 {
+		ok := false
+		for _, constraint := range c.PermittedDNSDomains {
+			ok = matchNameConstraint(opts.DNSName, constraint)
+			if ok {
+				break
+			}
+		}
+
+		if !ok {
+			return CertificateInvalidError{c, CANotAuthorizedForThisName}
+		}
+	}
+
+	// KeyUsage status flags are ignored. From Engineering Security, Peter
+	// Gutmann: A European government CA marked its signing certificates as
+	// being valid for encryption only, but no-one noticed. Another
+	// European CA marked its signature keys as not being valid for
+	// signatures. A different CA marked its own trusted root certificate
+	// as being invalid for certificate signing. Another national CA
+	// distributed a certificate to be used to encrypt data for the
+	// country’s tax authority that was marked as only being usable for
+	// digital signatures but not for encryption. Yet another CA reversed
+	// the order of the bit flags in the keyUsage due to confusion over
+	// encoding endianness, essentially setting a random keyUsage in
+	// certificates that it issued. Another CA created a self-invalidating
+	// certificate by adding a certificate policy statement stipulating
+	// that the certificate had to be used strictly as specified in the
+	// keyUsage, and a keyUsage containing a flag indicating that the RSA
+	// encryption key could only be used for Diffie-Hellman key agreement.
+
+	if certType == intermediateCertificate && (!c.BasicConstraintsValid || !c.IsCA) {
+		return CertificateInvalidError{c, NotAuthorizedToSign}
+	}
+
+	if c.BasicConstraintsValid && c.MaxPathLen >= 0 {
+		numIntermediates := len(currentChain) - 1
+		if numIntermediates > c.MaxPathLen {
+			return CertificateInvalidError{c, TooManyIntermediates}
+		}
+	}
+
+	return nil
+}
+
+// Verify attempts to verify c by building one or more chains from c to a
+// certificate in opts.Roots, using certificates in opts.Intermediates if
+// needed. If successful, it returns one or more chains where the first
+// element of the chain is c and the last element is from opts.Roots.
+//
+// If opts.Roots is nil and system roots are unavailable the returned error
+// will be of type SystemRootsError.
+//
+// WARNING: this doesn't do any revocation checking.
+func (c *Certificate) Verify(opts VerifyOptions) (chains [][]*Certificate, err error) {
+	// Platform-specific verification needs the ASN.1 contents so
+	// this makes the behavior consistent across platforms.
+	if len(c.Raw) == 0 {
+		return nil, errNotParsed
+	}
+	if opts.Intermediates != nil {
+		for _, intermediate := range opts.Intermediates.certs {
+			if len(intermediate.Raw) == 0 {
+				return nil, errNotParsed
+			}
+		}
+	}
+
+	// Use Windows's own verification and chain building.
+	if opts.Roots == nil && runtime.GOOS == "windows" {
+		return c.systemVerify(&opts)
+	}
+
+	if len(c.UnhandledCriticalExtensions) > 0 {
+		return nil, UnhandledCriticalExtension{}
+	}
+
+	if opts.Roots == nil {
+		opts.Roots = systemRootsPool()
+		if opts.Roots == nil {
+			return nil, SystemRootsError{systemRootsErr}
+		}
+	}
+
+	err = c.isValid(leafCertificate, nil, &opts)
+	if err != nil {
+		return
+	}
+
+	if len(opts.DNSName) > 0 {
+		err = c.VerifyHostname(opts.DNSName)
+		if err != nil {
+			return
+		}
+	}
+
+	var candidateChains [][]*Certificate
+	if opts.Roots.contains(c) {
+		candidateChains = append(candidateChains, []*Certificate{c})
+	} else {
+		if candidateChains, err = c.buildChains(make(map[int][][]*Certificate), []*Certificate{c}, &opts); err != nil {
+			return nil, err
+		}
+	}
+
+	keyUsages := opts.KeyUsages
+	if len(keyUsages) == 0 {
+		keyUsages = []ExtKeyUsage{ExtKeyUsageServerAuth}
+	}
+
+	// If any key usage is acceptable then we're done.
+	for _, usage := range keyUsages {
+		if usage == ExtKeyUsageAny {
+			chains = candidateChains
+			return
+		}
+	}
+
+	for _, candidate := range candidateChains {
+		if checkChainForKeyUsage(candidate, keyUsages) {
+			chains = append(chains, candidate)
+		}
+	}
+
+	if len(chains) == 0 {
+		err = CertificateInvalidError{c, IncompatibleUsage}
+	}
+
+	return
+}
+
+func appendToFreshChain(chain []*Certificate, cert *Certificate) []*Certificate {
+	n := make([]*Certificate, len(chain)+1)
+	copy(n, chain)
+	n[len(chain)] = cert
+	return n
+}
+
+func (c *Certificate) buildChains(cache map[int][][]*Certificate, currentChain []*Certificate, opts *VerifyOptions) (chains [][]*Certificate, err error) {
+	possibleRoots, failedRoot, rootErr := opts.Roots.findVerifiedParents(c)
+nextRoot:
+	for _, rootNum := range possibleRoots {
+		root := opts.Roots.certs[rootNum]
+
+		for _, cert := range currentChain {
+			if cert.Equal(root) {
+				continue nextRoot
+			}
+		}
+
+		err = root.isValid(rootCertificate, currentChain, opts)
+		if err != nil {
+			continue
+		}
+		chains = append(chains, appendToFreshChain(currentChain, root))
+	}
+
+	possibleIntermediates, failedIntermediate, intermediateErr := opts.Intermediates.findVerifiedParents(c)
+nextIntermediate:
+	for _, intermediateNum := range possibleIntermediates {
+		intermediate := opts.Intermediates.certs[intermediateNum]
+		for _, cert := range currentChain {
+			if cert.Equal(intermediate) {
+				continue nextIntermediate
+			}
+		}
+		err = intermediate.isValid(intermediateCertificate, currentChain, opts)
+		if err != nil {
+			continue
+		}
+		var childChains [][]*Certificate
+		childChains, ok := cache[intermediateNum]
+		if !ok {
+			childChains, err = intermediate.buildChains(cache, appendToFreshChain(currentChain, intermediate), opts)
+			cache[intermediateNum] = childChains
+		}
+		chains = append(chains, childChains...)
+	}
+
+	if len(chains) > 0 {
+		err = nil
+	}
+
+	if len(chains) == 0 && err == nil {
+		hintErr := rootErr
+		hintCert := failedRoot
+		if hintErr == nil {
+			hintErr = intermediateErr
+			hintCert = failedIntermediate
+		}
+		err = UnknownAuthorityError{c, hintErr, hintCert}
+	}
+
+	return
+}
+
+func matchHostnames(pattern, host string) bool {
+	host = strings.TrimSuffix(host, ".")
+	pattern = strings.TrimSuffix(pattern, ".")
+
+	if len(pattern) == 0 || len(host) == 0 {
+		return false
+	}
+
+	patternParts := strings.Split(pattern, ".")
+	hostParts := strings.Split(host, ".")
+
+	if len(patternParts) != len(hostParts) {
+		return false
+	}
+
+	for i, patternPart := range patternParts {
+		if i == 0 && patternPart == "*" {
+			continue
+		}
+		if patternPart != hostParts[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// toLowerCaseASCII returns a lower-case version of in. See RFC 6125 6.4.1. We use
+// an explicitly ASCII function to avoid any sharp corners resulting from
+// performing Unicode operations on DNS labels.
+func toLowerCaseASCII(in string) string {
+	// If the string is already lower-case then there's nothing to do.
+	isAlreadyLowerCase := true
+	for _, c := range in {
+		if c == utf8.RuneError {
+			// If we get a UTF-8 error then there might be
+			// upper-case ASCII bytes in the invalid sequence.
+			isAlreadyLowerCase = false
+			break
+		}
+		if 'A' <= c && c <= 'Z' {
+			isAlreadyLowerCase = false
+			break
+		}
+	}
+
+	if isAlreadyLowerCase {
+		return in
+	}
+
+	out := []byte(in)
+	for i, c := range out {
+		if 'A' <= c && c <= 'Z' {
+			out[i] += 'a' - 'A'
+		}
+	}
+	return string(out)
+}
+
+// VerifyHostname returns nil if c is a valid certificate for the named host.
+// Otherwise it returns an error describing the mismatch.
+func (c *Certificate) VerifyHostname(h string) error {
+	// IP addresses may be written in [ ].
+	candidateIP := h
+	if len(h) >= 3 && h[0] == '[' && h[len(h)-1] == ']' {
+		candidateIP = h[1 : len(h)-1]
+	}
+	if ip := net.ParseIP(candidateIP); ip != nil {
+		// We only match IP addresses against IP SANs.
+		// https://tools.ietf.org/html/rfc6125#appendix-B.2
+		for _, candidate := range c.IPAddresses {
+			if ip.Equal(candidate) {
+				return nil
+			}
+		}
+		return HostnameError{c, candidateIP}
+	}
+
+	lowered := toLowerCaseASCII(h)
+
+	if len(c.DNSNames) > 0 {
+		for _, match := range c.DNSNames {
+			if matchHostnames(toLowerCaseASCII(match), lowered) {
+				return nil
+			}
+		}
+		// If Subject Alt Name is given, we ignore the common name.
+	} else if matchHostnames(toLowerCaseASCII(c.Subject.CommonName), lowered) {
+		return nil
+	}
+
+	return HostnameError{c, h}
+}
+
+func checkChainForKeyUsage(chain []*Certificate, keyUsages []ExtKeyUsage) bool {
+	usages := make([]ExtKeyUsage, len(keyUsages))
+	copy(usages, keyUsages)
+
+	if len(chain) == 0 {
+		return false
+	}
+
+	usagesRemaining := len(usages)
+
+	// We walk down the list and cross out any usages that aren't supported
+	// by each certificate. If we cross out all the usages, then the chain
+	// is unacceptable.
+
+NextCert:
+	for i := len(chain) - 1; i >= 0; i-- {
+		cert := chain[i]
+		if len(cert.ExtKeyUsage) == 0 && len(cert.UnknownExtKeyUsage) == 0 {
+			// The certificate doesn't have any extended key usage specified.
+			continue
+		}
+
+		for _, usage := range cert.ExtKeyUsage {
+			if usage == ExtKeyUsageAny {
+				// The certificate is explicitly good for any usage.
+				continue NextCert
+			}
+		}
+
+		const invalidUsage ExtKeyUsage = -1
+
+	NextRequestedUsage:
+		for i, requestedUsage := range usages {
+			if requestedUsage == invalidUsage {
+				continue
+			}
+
+			for _, usage := range cert.ExtKeyUsage {
+				if requestedUsage == usage {
+					continue NextRequestedUsage
+				} else if requestedUsage == ExtKeyUsageServerAuth &&
+					(usage == ExtKeyUsageNetscapeServerGatedCrypto ||
+						usage == ExtKeyUsageMicrosoftServerGatedCrypto) {
+					// In order to support COMODO
+					// certificate chains, we have to
+					// accept Netscape or Microsoft SGC
+					// usages as equal to ServerAuth.
+					continue NextRequestedUsage
+				}
+			}
+
+			usages[i] = invalidUsage
+			usagesRemaining--
+			if usagesRemaining == 0 {
+				return false
+			}
+		}
+	}
+
+	return true
+}