RSA是1977年由罗纳德·李维斯特(Ron Rivest)、阿迪·萨莫尔(Adi Shamir)和伦纳德·阿德曼(Leonard Adleman)一起提出的。当时他们三人都在麻省理工学院工作。RSA就是他们三人姓氏开头字母拼在一起组成的。
RSA解决了对称加密的一个不足,比如AES算法加密和解密时使用的是同一个秘钥,因此这个秘钥不能公开,因此对于需要公开秘钥的场合,我们需要在加密和解密过程中使用不同的秘钥,加密使用的公钥可以公开,解密使用的私钥要保密,这就是非对称加密的好处。
常用的开发语言来实现RSA加密:
RSA非对称加密算法实现:Java
RSA非对称加密算法实现:C#
RSA非对称加密算法实现:Golang
RSA非对称加密算法实现:Python
公钥与私钥
公钥与私钥是成对的,一般的,我们认为的是公钥加密、私钥解密、私钥签名、公钥验证,有人说成私钥加密,公钥解密时不对的。
公钥与私钥的生成有多种方式,可以通过程序生成(下文具体实现),可以通过openssl工具:
# 生成一个私钥,推荐使用1024位的秘钥,秘钥以pem格式保存到-out参数指定的文件中,采用PKCS1格式
openssl genrsa -out rsa.pem 1024
# 生成与私钥对应的公钥,生成的是Subject Public Key,一般配合PKCS8格式私钥使用
openssl rsa -in rsa.pem -pubout -out rsa.pub
RSA生成公钥与私钥一般有两种格式:PKCS1和PKCS8,上面的命令生成的秘钥是PKCS1格式的,而公钥是Subject Public Key,一般配合PKCS8格式私钥使用,所以就可能会涉及到PKCS1和PKCS8之间的转换:
# PKCS1格式私钥转换为PKCS8格式私钥,私钥直接输出到-out参数指定的文件中
openssl pkcs8 -topk8 -inform PEM -in rsa.pem -outform pem -nocrypt -out rsa_pkcs8.pem
# PKCS8格式私钥转换为PKCS1格式私钥,私钥直接输出到-out参数指定的文件中
openssl rsa -in rsa_pkcs8.pem -out rsa_pkcs1.pem
# PKCS1格式公钥转换为PKCS8格式公钥,转换后的内容直接输出
openssl rsa -pubin -in rsa.pub -RSAPublicKey_out
# PKCS8格式公钥转换为PKCS1格式公钥,转换后的内容直接输出
openssl rsa -RSAPublicKey_in -pubout -in rsa.pub
现实中,我们往往从pem、crt、pfx文件获取公私和私钥,crt、pfx的制作可以参考:
简单的制作ssl证书,并在nginx和IIS中使用
,或者使用现成的:
https://pan.baidu.com/s/1MJ5YmuZiLBnf-DfNR_6D7A
(提取码:c6tj),密码都是:123456
Golang实现
为了方便读取pem、crt、pfx文件中的公私和私钥,这里我使用了第三方的包:golang.org/x/crypto/pkcs12,可以使用go get安装:go get -u golang.org/x/crypto/pkcs12
安装之后,封装一个工具包rsautil.go:
package rsautil
import (
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/asn1"
"encoding/pem"
"fmt"
"golang.org/x/crypto/pkcs12"
"io"
"io/ioutil"
"os"
"strconv"
//从Pem文件中读取秘钥
func ReadFromPem(pemFile string) ([]byte, error) {
buffer, err := ioutil.ReadFile(pemFile)
if err != nil {
return nil, err
block, _ := pem.Decode(buffer)
return block.Bytes, nil
//从pfx文件中读取公私密钥(需要安装golang.org/x/crypto/pkcs12)
func ReadFromPfx(pfxFile, password string, usePKCS8 bool) ([]byte, []byte) {
buffer, err := ioutil.ReadFile(pfxFile)
if err != nil {
panic(err)
privateKeyInterface, certificate, err := pkcs12.Decode(buffer, password)
if err != nil {
panic(err)
privateKey := privateKeyInterface.(*rsa.PrivateKey)
publicKey := certificate.PublicKey.(*rsa.PublicKey)
var (
privateKeyBuffer []byte
publicKeyBuffer []byte
if usePKCS8 {
privateKeyBuffer, err = x509.MarshalPKCS8PrivateKey(privateKey)
if err != nil {
panic(err)
publicKeyBuffer, err = x509.MarshalPKIXPublicKey(publicKey)
if err != nil {
panic(err)
} else {
privateKeyBuffer = x509.MarshalPKCS1PrivateKey(privateKey)
publicKeyBuffer = x509.MarshalPKCS1PublicKey(publicKey)
return publicKeyBuffer, privateKeyBuffer
//从crt中读取公钥
func ReadPublicKeyFromCrt(crtFile string, usePKCS8 bool) ([]byte, error) {
buffer, err := ioutil.ReadFile(crtFile)
if err != nil {
return nil, err
certDERBlock, _ := pem.Decode(buffer)
certificate, err := x509.ParseCertificate(certDERBlock.Bytes)
if err != nil {
return nil, err
publicKey := certificate.PublicKey.(*rsa.PublicKey)
var publicKeyBuffer []byte
if usePKCS8 {
publicKeyBuffer, err = x509.MarshalPKIXPublicKey(publicKey)
} else {
publicKeyBuffer = x509.MarshalPKCS1PublicKey(publicKey)
if err != nil {
return nil, err
return publicKeyBuffer, nil
//将秘钥写入Pem文件
func WriteToPem(isPrivateKey bool, buffer []byte, pemFile string) error {
var _type string
if isPrivateKey {
_type = "RSA PRIVATE KEY"
} else {
_type = "RSA PUBLIC KEY"
block := &pem.Block{
Type: _type, //这个字符串随便写
Bytes: buffer,
file, err := os.Create(pemFile)
if err != nil {
return err
return pem.Encode(file, block)
//Pkcs1转换为Pkcs8
func Pkcs1ToPkcs8(isPrivateKey bool, buffer []byte) []byte {
var (
oid = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
info interface{}
if isPrivateKey {
val := struct {
Version int
Algo []asn1.ObjectIdentifier
PrivateKey []byte
val.Version = 0
val.Algo = []asn1.ObjectIdentifier{oid}
val.PrivateKey = buffer
info = val
} else {
val := struct {
Algo pkix.AlgorithmIdentifier
BitString asn1.BitString
val.Algo.Algorithm = oid
val.Algo.Parameters = asn1.NullRawValue
val.BitString.Bytes = buffer
val.BitString.BitLength = 8 * len(buffer)
info = val
b, err := asn1.Marshal(info)
if err != nil {
panic(err)
return b
//Pkcs8转换为Pkcs1
func Pkcs8ToPkcs1(isPrivateKey bool, buffer []byte) []byte {
if isPrivateKey {
val := struct {
Version int
Algo pkix.AlgorithmIdentifier
PrivateKey []byte
_, err := asn1.Unmarshal(buffer, &val)
if err != nil {
panic(err)
return val.PrivateKey
} else {
val := struct {
Algo pkix.AlgorithmIdentifier
BitString asn1.BitString
_, err := asn1.Unmarshal(buffer, &val)
if err != nil {
panic(err)
return val.BitString.Bytes
//生成公私钥
//usePKCS8:是否使用pkcs8
func GenerateRsaKey(usePKCS8 bool) ([]byte, []byte) {
//生成私钥
privateKey, err := rsa.GenerateKey(rand.Reader, 1024) //1024位
if err != nil {
panic(err)
//公钥
publicKey := privateKey.PublicKey
var (
privateKeyBuffer []byte
publicKeyBuffer []byte
if usePKCS8 {
privateKeyBuffer, err = x509.MarshalPKCS8PrivateKey(privateKey)
if err != nil {
panic(err)
publicKeyBuffer, err = x509.MarshalPKIXPublicKey(&publicKey)
if err != nil {
panic(err)
} else {
privateKeyBuffer = x509.MarshalPKCS1PrivateKey(privateKey)
publicKeyBuffer = x509.MarshalPKCS1PublicKey(&publicKey)
return publicKeyBuffer, privateKeyBuffer
func parsePkcsKey(buffer []byte, isPrivateKey, usePKCS8 bool) (interface{}, error) {
var (
err error
keyInterface interface{}
if isPrivateKey {
if usePKCS8 {
keyInterface, err = x509.ParsePKCS8PrivateKey(buffer)
} else {
keyInterface, err = x509.ParsePKCS1PrivateKey(buffer)
} else {
if usePKCS8 {
keyInterface, err = x509.ParsePKIXPublicKey(buffer)
} else {
keyInterface, err = x509.ParsePKCS1PublicKey(buffer)
if err != nil {
return nil, err
return keyInterface, nil
//RSA加密
func RsaEncrypt(value string, publicKey []byte, usePKCS8 bool) (string, error) {
keyInterface, err := parsePkcsKey(publicKey, false, usePKCS8)
if err != nil {
return "", err
rsaPublicKey := keyInterface.(*rsa.PublicKey)
buffer, err := rsa.EncryptPKCS1v15(rand.Reader, rsaPublicKey, []byte(value))
if err != nil {
return "", err
//以hex格式数值输出
encryptText := fmt.Sprintf("%x", buffer)
return encryptText, nil
//RSA解密
func RsaDecrypt(value string, privateKey []byte, usePKCS8 bool) (string, error) {
//将hex格式数据转换为byte切片
valueBytes := []byte(value)
var buffer = make([]byte, len(valueBytes)/2)
for i := 0; i < len(buffer); i++ {
b, err := strconv.ParseInt(value[i*2:i*2+2], 16, 10)
if err != nil {
return "", err
buffer[i] = byte(b)
keyInterface, err := parsePkcsKey(privateKey, true, usePKCS8)
if err != nil {
return "", err
key := keyInterface.(*rsa.PrivateKey)
buffer, err = rsa.DecryptPKCS1v15(rand.Reader, key, buffer)
return string(buffer), nil
//RSA签名
func Sign(value string, privateKey []byte, hash crypto.Hash, usePKCS8 bool) (string, error) {
keyInterface, err := parsePkcsKey(privateKey, true, usePKCS8)
if err != nil {
return "", err
key := keyInterface.(*rsa.PrivateKey)
var _hash = hash.New()
if _, err := io.WriteString(_hash, value); err != nil {
return "", err
hashed := _hash.Sum(nil)
result, err := rsa.SignPKCS1v15(rand.Reader, key, hash, hashed)
if err != nil {
return "", err
//以hex格式数值输出
encryptText := fmt.Sprintf("%x", result)
return encryptText, nil
//RSA验证签名
func Verify(value string, publicKey []byte, signature string, hash crypto.Hash, usePKCS8 bool) error {
//将hex格式数据转换为byte切片
valueBytes := []byte(signature)
var buffer = make([]byte, len(valueBytes)/2)
for i := 0; i < len(buffer); i++ {
b, err := strconv.ParseInt(signature[i*2:i*2+2], 16, 10)
if err != nil {
return err
buffer[i] = byte(b)
keyInterface, err := parsePkcsKey(publicKey, false, usePKCS8)
if err != nil {
return err
key := keyInterface.(*rsa.PublicKey)
var _hash = hash.New()
if _, err := io.WriteString(_hash, value); err != nil {
return err
hashed := _hash.Sum(nil)
return rsa.VerifyPKCS1v15(key, hash, hashed, buffer)
rsautil
可以使用生成RSA的公私秘钥:
//生成Rsa
publicKey, privateKey := rsautil.GenerateRsaKey(usePKCS8)
生成秘钥后,需要保存,一般保存到pem文件中:
//保存到Pem文件,filePath是文件目录
rsautil.WriteToPem(false, publicKey, filepath.Join(filePath, "rsa.pub"))
rsautil.WriteToPem(true, privateKey, filepath.Join(filePath, "rsa.pem"))
从pem文件中读取:
//从Pem文件读取秘钥,filePath是文件目录
publicKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "rsa.pub"))
privateKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "rsa.pem"))
还可以从crt证书中读取公钥,而crt文件不包含私钥,因此需要单独获取私钥:
//从crt文件中读取公钥,filePath是文件目录
publicKey, _ := rsautil.ReadPublicKeyFromCrt(filepath.Join(filePath, "demo.crt"), usePKCS8)
privateKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "demo.key"))
pfx文件中包含了公钥和私钥,可以很方便就读取到:
//从pfx文件中读取秘钥,filePath是文件目录
publicKey, privateKey := rsautil.ReadFromPfx(filepath.Join(filePath, "demo.pfx"), "123456", usePKCS8)
有时候我们还可能需要进行秘钥的转换:
//Pkcs8格式公钥转换为Pkcs1格式公钥
publicKey = rsautil.Pkcs8ToPkcs1(false, publicKey)
// Pkcs8格式私钥转换为Pkcs1格式私钥
privateKey = rsautil.Pkcs8ToPkcs1(true, privateKey)
// Pkcs1格式公钥转换为Pkcs8格式公钥
publicKey = rsautil.Pkcs1ToPkcs8(false, publicKey)
// Pkcs1格式私钥转换为Pkcs8格式私钥
privateKey = rsautil.Pkcs1ToPkcs8(true, privateKey)
有了公钥和私钥,接下就就能实现加密、解密、签名、验证签名等操作了:
encryptText, _ := rsautil.RsaEncrypt(text, publicKey, usePKCS8)
fmt.Printf("【%s】经过【RSA】加密后:%s\n", text, encryptText)
decryptText, _ := rsautil.RsaDecrypt(encryptText, privateKey, usePKCS8)
fmt.Printf("【%s】经过【RSA】解密后:%s\n", encryptText, decryptText)
signature, _ := rsautil.Sign(text, privateKey, crypto.MD5, usePKCS8)
fmt.Printf("【%s】经过【RSA】签名后:%s\n", text, signature)
result := rsautil.Verify(text, publicKey, signature, crypto.MD5, usePKCS8) == nil
fmt.Printf("【%s】的签名【%s】经过【RSA】验证后结果是:"+strconv.FormatBool(result), text, signature)
完整的demo代码:
package main
import (
"crypto"
"demo/rsautil"
"fmt"
"os"
"path/filepath"
"strconv"
func main() {
text := "上山打老虎"
usePKCS8 := true // usePKCS8=true表示是否成PKCS8格式的公私秘钥,否则乘车PKCS1格式的公私秘钥
path, _ := os.Executable()
filePath := filepath.Dir(path)
fmt.Printf("文件路径:%s\n", filePath) // 存放pem,crt,pfx等文件的目录
//生成Rsa
publicKey, privateKey := rsautil.GenerateRsaKey(usePKCS8)
//从Pem文件读取秘钥,filePath是文件目录
//publicKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "rsa.pub"))
//privateKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "rsa.pem"))
//从pfx文件中读取秘钥,filePath是文件目录
//publicKey, privateKey := rsautil.ReadFromPfx(filepath.Join(filePath, "demo.pfx"), "123456", usePKCS8)
//从crt文件中读取公钥,filePath是文件目录
//publicKey, _ := rsautil.ReadPublicKeyFromCrt(filepath.Join(filePath, "demo.crt"), usePKCS8)
//privateKey, _ := rsautil.ReadFromPem(filepath.Join(filePath, "demo.key"))
//保存到Pem文件,filePath是文件目录
rsautil.WriteToPem(false, publicKey, filepath.Join(filePath, "rsa.pub"))
rsautil.WriteToPem(true, privateKey, filepath.Join(filePath, "rsa.pem"))
//Pkcs8格式公钥转换为Pkcs1格式公钥
publicKey = rsautil.Pkcs8ToPkcs1(false, publicKey)
// Pkcs8格式私钥转换为Pkcs1格式私钥
privateKey = rsautil.Pkcs8ToPkcs1(true, privateKey)
// Pkcs1格式公钥转换为Pkcs8格式公钥
publicKey = rsautil.Pkcs1ToPkcs8(false, publicKey)
// Pkcs1格式私钥转换为Pkcs8格式私钥
privateKey = rsautil.Pkcs1ToPkcs8(true, privateKey)
encryptText, _ := rsautil.RsaEncrypt(text, publicKey, usePKCS8)
fmt.Printf("【%s】经过【RSA】加密后:%s\n", text, encryptText)
decryptText, _ := rsautil.RsaDecrypt(encryptText, privateKey, usePKCS8)
fmt.Printf("【%s】经过【RSA】解密后:%s\n", encryptText, decryptText)
signature, _ := rsautil.Sign(text, privateKey, crypto.MD5, usePKCS8)
fmt.Printf("【%s】经过【RSA】签名后:%s\n", text, signature)
result := rsautil.Verify(text, publicKey, signature, crypto.MD5, usePKCS8) == nil
fmt.Printf("【%s】的签名【%s】经过【RSA】验证后结果是:"+strconv.FormatBool(result), text, signature)