golang RSA公钥密钥生成及加解密

1.公钥私钥的应用

    对于数据传输安全这块，加密是必要的；首先后端生成公钥私钥对及索引key，继而存储到相应的缓存库；然后将公钥和索引key返回给前端，前端通过公钥加密需要传输的明文；最后将密文和索引key传递给后端，后端通过索引key在缓存库中匹配相应的私钥，通过对应的私钥解密前端传来的密文。每次请求都会生成不同的公钥秘钥对，这样安全性会更高

2.公钥密钥对的生成

package main

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"log"
	"testing"
)

func TestKeyGenerate(t *testing.T) {
	//var bits int
	//flag.IntVar(&bits, "b", 1024, "密钥长度，默认为1024位")
	if err := GenRsaKey(1024); err != nil {
		log.Fatal("密钥文件生成失败！")
	}

	log.Println("密钥文件生成成功！")
}

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)
	priBlock := &pem.Block{
		Type:  "RSA PRIVATE KEY",
		Bytes: derStream,
	}

	fmt.Printf("=======私钥文件内容=========%v", string(pem.EncodeToMemory(priBlock)))
	// 生成公钥文件
	publicKey := &privateKey.PublicKey
	derPkix, err := x509.MarshalPKIXPublicKey(publicKey)
	if err != nil {
		return err
	}
	publicBlock := &pem.Block{
		Type:  "PUBLIC KEY",
		Bytes: derPkix,
	}

	fmt.Printf("=======公钥文件内容=========%v", string(pem.EncodeToMemory(publicBlock)))

	if err != nil {
		return err
	}
	return nil
}

3.加解密过程

package main

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"errors"
	"fmt"
	"testing"
)

// 可通过openssl产生
//openssl genrsa -out rsa_private_key.pem 1024
var privateKey = []byte(`
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
`)

//openssl
//openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem
var publicKey = []byte(`
-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDP2z9C4/iLNrlzP/RYuKNdJ3Mz
vYh7j2yrGAo9MvZGy4hvCJfYdjS+SSXn++YEIORr+9X+SMHu9gHGi3kBxTbEUmVI
c0ee13xmh12mpcu6QoOGseD7Q2dPx9Kjc21jeqJU3WS5QSelMN3DZVLrwt9Hjy8T
w0Cxp0yhkCPZ3ZVPUQIDAQAB
-----END PUBLIC KEY-----
`)

// 加密
func RsaEncrypt(origData []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, origData)
}

// 解密
func RsaDecrypt(ciphertext []byte) ([]byte, error) {
	//解密
	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)
}

func TestSecurity(t *testing.T) {
	data, _ := RsaEncrypt([]byte("hello world"))
	fmt.Printf("加密后的密文:%s", base64.StdEncoding.EncodeToString(data))
	origData, _ := RsaDecrypt(data)
	fmt.Println("start===================end")
	fmt.Printf("解密后的明文:%s", string(origData))
}