加密包装

crypto/rsa.go

@@ -0,0 +1,116 @@
+package crypto
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"strconv"
+)
+
+
+
+type rsaInstance struct {
+	hashOptions
+	prk *rsa.PrivateKey
+	puk *rsa.PublicKey
+}
+
+type rsaOption func(o *rsaInstance) error
+
+func NewRsa(h Hash, opts ...rsaOption) (*rsaInstance, error) {
+	o := &rsaInstance{}
+
+	sh := crypto.Hash(h)
+	if !sh.Available() {
+		return nil, errors.New("unknown hash value " + strconv.Itoa(int(h)))
+	}
+
+	o.h = sh
+
+	for _, f := range opts {
+		if err := f(o); err != nil {
+			return nil, err
+		}
+	}
+
+	// 未设置私钥时随机生成密钥
+	if o.prk == nil {
+		prk, err := rsa.GenerateKey(rand.Reader, defaultRsaBits)
+		if err != nil {
+			return nil, err
+		}
+
+		o.prk = prk
+	}
+
+	// 公钥未设置时从私钥导出
+	if o.puk == nil {
+		o.puk = &o.prk.PublicKey
+	}
+
+	return o, nil
+}
+
+func ParsePKCS1PrivateKey(p []byte) rsaOption {
+	return func(o *rsaInstance) error {
+		block, _ := pem.Decode(p)
+		if block == nil {
+			return errors.New("failed to decode private key")
+		}
+
+		prk, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+		if err != nil {
+			return err
+		}
+
+		o.prk = prk
+
+		return nil
+	}
+}
+
+func ParsePKIXPublicKey(p []byte) rsaOption {
+	return func(o *rsaInstance) error {
+		block, _ := pem.Decode(p)
+		if block == nil {
+			return errors.New("failed to decode public key")
+		}
+
+		k, err := x509.ParsePKIXPublicKey(block.Bytes)
+		if err != nil {
+			return err
+		}
+
+		puk := k.(*rsa.PublicKey)
+
+		o.puk = puk
+
+		return nil
+	}
+}
+
+func (o *rsaInstance) Encrypt(msg []byte) ([]byte, error) {
+	return rsa.EncryptPKCS1v15(rand.Reader, o.puk, msg)
+}
+
+func (o *rsaInstance) Decrypt(ciphertext []byte) ([]byte, error) {
+	return rsa.DecryptPKCS1v15(rand.Reader, o.prk, ciphertext)
+}
+
+func (o *rsaInstance) Sign(msg []byte) ([]byte, error) {
+	hashed := o.getHash(msg)
+	sign, err := rsa.SignPKCS1v15(rand.Reader, o.prk, o.h, hashed)
+	return sign, err
+}
+
+func (o *rsaInstance) Verify(msg, sign []byte) bool {
+	hashed := o.getHash(msg)
+	if err := rsa.VerifyPKCS1v15(o.puk, o.h, hashed, sign); err != nil {
+		return false
+	}
+
+	return true
+}