首先由genkey.go生成公钥和私文件，在rsa.go里使用生成的公钥和私钥进行加密和解密
//文件 genkey.go
//生成公钥和私钥 pem文件
```go
package main
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"flag"
"log"
"os"
)
func main() {
var bits int
flag.IntVar(&bits, "b", 1024, "秘钥长度，默认为1024")
if err := GenRsaKey(bits); err != nil {
log.Fatal("秘钥文件生成失败")
}
log.Println("秘钥文件生成成功")
}
//生成 私钥和公钥文件
func GenRsaKey(bits int) error {
//生成私钥文件
privateKey, err := rsa.GenerateKey(rand.Reader, bits)
if err != nil {
return err
}
derStream := x509.MarshalPKCS1PrivateKey(privateKey)
block := &pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: derStream,
}
file, err := os.Create("private.pem")
if err != nil {
return err
}
err = pem.Encode(file, block)
if err != nil {
return err
}
//生成公钥文件
publicKey := &privateKey.PublicKey
defPkix, err := x509.MarshalPKIXPublicKey(publicKey)
if err != nil {
return err
}
block = &pem.Block{
Type: "RSA PUBLIC KEY",
Bytes: defPkix,
}
file, err = os.Create("public.pem")
if err != nil {
return err
}
err = pem.Encode(file, block)
if err != nil {
return err
}
return nil
}
//rsa.go
//公钥加密私钥解密 私钥签名公钥验证
package main
import (
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"os"
)
var privateKey, publicKey []byte
func init() {
var err error
publicKey, err = ioutil.ReadFile("public.pem")
if err != nil {
os.Exit(-1)
}
privateKey, err = ioutil.ReadFile("private.pem")
if err != nil {
os.Exit(-1)
}
//fmt.Printf("%s\n", publicKey)
//fmt.Printf("%s\n", privateKey)
}
func main() {
var theMsg = "the message you want to encode 你好 世界"
fmt.Println("Source:", theMsg)
//私钥签名
sig, _ := RsaSign([]byte(theMsg))
fmt.Println(string(sig))
//公钥验证
fmt.Println(RsaSignVer([]byte(theMsg), sig))
//公钥加密
// enc, _ := RsaEncrypt([]byte(theMsg))
// fmt.Println("Encrypted:", string(enc))
// //私钥解密
// decstr, _ := RsaDecrypt(enc)
// fmt.Println("Decrypted:", string(decstr))
}
//私钥签名
func RsaSign(data []byte) ([]byte, error) {
h := sha256.New()
h.Write(data)
hashed := h.Sum(nil)
//获取私钥
block, _ := pem.Decode(privateKey)
if block == nil {
return nil, errors.New("private key error")
}
//解析PKCS1格式的私钥
priv, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
return nil, err
}
return rsa.SignPKCS1v15(rand.Reader, priv, crypto.SHA256, hashed)
}
//公钥验证
func RsaSignVer(data []byte, signature []byte) error {
hashed := sha256.Sum256(data)
block, _ := pem.Decode(publicKey)
if block == nil {
return errors.New("public key error")
}
// 解析公钥
pubInterface, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
return err
}
// 类型断言
pub := pubInterface.(*rsa.PublicKey)
//验证签名
return rsa.VerifyPKCS1v15(pub, crypto.SHA256, hashed[:], signature)
}
// 公钥加密
func RsaEncrypt(data []byte) ([]byte, error) {
//解密pem格式的公钥
block, _ := pem.Decode(publicKey)
if block == nil {
return nil, errors.New("public key error")
}
// 解析公钥
pubInterface, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
return nil, err
}
// 类型断言
pub := pubInterface.(*rsa.PublicKey)
//加密
return rsa.EncryptPKCS1v15(rand.Reader, pub, data)
}
// 私钥解密
func RsaDecrypt(ciphertext []byte) ([]byte, error) {
//获取私钥
block, _ := pem.Decode(privateKey)
if block == nil {
return nil, errors.New("private key error!")
}
//解析PKCS1格式的私钥
priv, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
return nil, err
}
// 解密
return rsa.DecryptPKCS1v15(rand.Reader, priv, ciphertext)
}
```
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