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golang数据传输加密解密

在前后端数据传输的过程中, 如果没有对数据加密, 抓包软件直接能看到我请求发的是什么数据,服务端给我返回的数据是什么。

并且可以用抓包软件修改响应数据返回给客户端,这样一来,客户端实际上接收到的数据并不是服务端给我的源数据,而是被第三者修改过的数据,如此一来,数据传输的安全就很有必要了。

解决方案可以用对称加密加密数据, 非对称加密加密key, 以客户端给服务端传输数据为例:

  1. 服务端生成一对RSA秘钥,私钥放在服务端(不可泄露),公钥下发给客户端。
  2. 客户端使用随机函数生成 key。
  3. 客户端使用随机的 key 对传输的数据用AES进行加密。
  4. 使用服务端给的公钥对 key进行加密。
  5. 客户端将使用AES加密的数据 以及使用 RSA公钥加密的key 一起发给服务端。
  6. 服务端拿到数据后,先使用私钥对加密的随机key进行解密,解密成功即可确定是客户端发来的数据,没有经过他人修改,然后使用解密成功的随机key对使用AES加密的数据进行解密,获取最终的数据。

这是单向的加密认证, 如果要实现双向加密验证, 就要生成两对公钥和私钥。

1. 步骤

1.1 生成rsa密钥对

生成私钥

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openssl genrsa -out private_client.pem 1024
openssl genrsa -out private_server.pem 1024

生成公钥

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openssl rsa -in private_client.pem -pubout -out public_client.pem
openssl rsa -in private_server.pem -pubout -out public_server.pem

1.2 加解密代码

  • rsa.go 非对称加密
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package encrypt

import (
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/pem"
"errors"
)

// BytesToPrivateKey bytes to private key
func BytesToPrivateKey(priv []byte) (*rsa.PrivateKey, error) {
block, _ := pem.Decode(priv)
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
var err error
if enc {
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
key, err := x509.ParsePKCS1PrivateKey(b)
if err != nil {
return nil, err
}
return key, nil
}

// BytesToPublicKey bytes to public key
func BytesToPublicKey(pub []byte) (*rsa.PublicKey, error) {
block, _ := pem.Decode(pub)
enc := x509.IsEncryptedPEMBlock(block)
b := block.Bytes
var err error
if enc {
b, err = x509.DecryptPEMBlock(block, nil)
if err != nil {
return nil, err
}
}
ifc, err := x509.ParsePKIXPublicKey(b)
if err != nil {
return nil, err
}
key, ok := ifc.(*rsa.PublicKey)
if !ok {
return nil, errors.New("not ok")
}
return key, nil
}

// EncryptWithPublicKey encrypts data with public key
func EncryptWithPublicKey(msg []byte, pub *rsa.PublicKey) ([]byte, error) {
hash := sha256.New()
ciphertext, err := rsa.EncryptOAEP(hash, rand.Reader, pub, msg, nil)
if err != nil {
return nil, err
}
return ciphertext, nil
}

// DecryptWithPrivateKey decrypts data with private key
func DecryptWithPrivateKey(ciphertext []byte, priv *rsa.PrivateKey) ([]byte, error) {
hash := sha256.New()
plaintext, err := rsa.DecryptOAEP(hash, rand.Reader, priv, ciphertext, nil)
if err != nil {
return nil, err
}
return plaintext, nil
}
  • aes.go 对称加密

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    package encrypt

    import (
    "bytes"
    "crypto/aes"
    "crypto/cipher"
    )

    // =================== CBC ======================
    func AesEncryptCBC(origData []byte, key []byte) (encrypted []byte) {
    // 分组秘钥
    // NewCipher该函数限制了输入k的长度必须为16, 24或者32
    block, _ := aes.NewCipher(key)
    blockSize := block.BlockSize() // 获取秘钥块的长度
    origData = pkcs5Padding(origData, blockSize) // 补全码
    blockMode := cipher.NewCBCEncrypter(block, key[:blockSize]) // 加密模式
    encrypted = make([]byte, len(origData)) // 创建数组
    blockMode.CryptBlocks(encrypted, origData) // 加密
    return encrypted
    }
    func AesDecryptCBC(encrypted []byte, key []byte) (decrypted []byte) {
    block, _ := aes.NewCipher(key) // 分组秘钥
    blockSize := block.BlockSize() // 获取秘钥块的长度
    blockMode := cipher.NewCBCDecrypter(block, key[:blockSize]) // 加密模式
    decrypted = make([]byte, len(encrypted)) // 创建数组
    blockMode.CryptBlocks(decrypted, encrypted) // 解密
    decrypted = pkcs5UnPadding(decrypted) // 去除补全码
    return decrypted
    }
    func pkcs5Padding(ciphertext []byte, blockSize int) []byte {
    padding := blockSize - len(ciphertext)%blockSize
    padtext := bytes.Repeat([]byte{byte(padding)}, padding)
    return append(ciphertext, padtext...)
    }
    func pkcs5UnPadding(origData []byte) []byte {
    length := len(origData)
    unpadding := int(origData[length-1])
    return origData[:(length - unpadding)]
    }

    // =================== ECB ======================
    func AesEncryptECB(origData []byte, key []byte) (encrypted []byte) {
    newCipher, _ := aes.NewCipher(generateKey(key))
    length := (len(origData) + aes.BlockSize) / aes.BlockSize
    plain := make([]byte, length*aes.BlockSize)
    copy(plain, origData)
    pad := byte(len(plain) - len(origData))
    for i := len(origData); i < len(plain); i++ {
    plain[i] = pad
    }
    encrypted = make([]byte, len(plain))
    // 分组分块加密
    for bs, be := 0, newCipher.BlockSize(); bs <= len(origData); bs, be = bs+newCipher.BlockSize(), be+newCipher.BlockSize() {
    newCipher.Encrypt(encrypted[bs:be], plain[bs:be])
    }

    return encrypted
    }
    func AesDecryptECB(encrypted []byte, key []byte) (decrypted []byte) {
    newCipher, _ := aes.NewCipher(generateKey(key))
    decrypted = make([]byte, len(encrypted))

    for bs, be := 0, newCipher.BlockSize(); bs < len(encrypted); bs, be = bs+newCipher.BlockSize(), be+newCipher.BlockSize() {
    newCipher.Decrypt(decrypted[bs:be], encrypted[bs:be])
    }

    trim := 0
    if len(decrypted) > 0 {
    trim = len(decrypted) - int(decrypted[len(decrypted)-1])
    }

    return decrypted[:trim]
    }
    func generateKey(key []byte) (genKey []byte) {
    genKey = make([]byte, 16)
    copy(genKey, key)
    for i := 16; i < len(key); {
    for j := 0; j < 16 && i < len(key); j, i = j+1, i+1 {
    genKey[j] ^= key[i]
    }
    }
    return genKey
    }

1.3 gin 中间件

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package middlewares

import (
"bytes"
"encoding/base64"
"encoding/json"
"io/ioutil"
"math/rand"
"net/http"
"public/encrypt"

"github.com/gin-gonic/gin"
)

type EncryptParam struct {
Key string `json:"key" form:"key"`
EncryptedData string `json:"encrypted_data" form:"encrypted_data"`
}

type EncryptResponseWriter struct {
gin.ResponseWriter
Buff *bytes.Buffer
}

func (e *EncryptResponseWriter) Write(p []byte) (int, error) {
return e.Buff.Write(p)
//return e.ResponseWriter.Write(p) // 不再写底层的这个write
}

func Encrypt() gin.HandlerFunc {
return func(c *gin.Context) {
encryptType := c.Request.Header.Get("bb-encrypt")
version := c.Request.Header.Get("bb-encrypt-ver")
if encryptType == "" || encryptType == "none" {
return
}

encryptWriter := &EncryptResponseWriter{c.Writer, bytes.NewBuffer(make([]byte, 0))}
c.Writer = encryptWriter

// 解密请求
if encryptType == "request" || encryptType == "all" {

param := EncryptParam{}
if err := c.Bind(&param); err != nil {
c.AbortWithStatus(http.StatusBadRequest)
common.Log.Errorf("Bind EncryptParam err: %s", err)
return
}
if param.Key == "" || param.EncryptedData == "" {
c.AbortWithStatus(http.StatusBadRequest)
common.Log.Error("EncryptedData is empty")
return
}

cert, err := Dao.GetCert(version, "server") // 此处是从数据库读取certs, 也可以本地读取文件
if err != nil {
c.AbortWithStatus(http.StatusBadRequest)
common.Log.Errorf("GetCert err: %s", err)
return
}

key, err := RsaDecryptData(cert.PrivateKey, param.Key)
if err != nil {
c.AbortWithStatus(http.StatusBadRequest)
common.Log.Errorf("RsaDecryptData err: %s", err)
return
}
data, err := AesDecryptData(key, param.EncryptedData)
if err != nil {
c.AbortWithStatus(http.StatusBadRequest)
common.Log.Errorf("AesDecryptData err: %s", err)
return
}

if c.Request.Method == http.MethodGet {
c.Request.URL.RawQuery = data
} else {
c.Request.Body = ioutil.NopCloser(bytes.NewBuffer([]byte(data)))
}

common.Log.Infof("%v-middlewares-decrypt raw: %v", c.Request.URL.Path, data)
}

c.Next()

normalReturn := func() {
if _, err := encryptWriter.ResponseWriter.Write(encryptWriter.Buff.Bytes()); err != nil {
common.Log.Error(err.Error())
}
}
if encryptWriter.Status() != http.StatusOK { // 不成功, 直接返回
normalReturn()
return
}

encryptWriter.Header().Set("bb-encrypted", version)
encryptWriter.Header().Set("bb-encrypt-ver", "0")
// 加密返回
if encryptType == "response" || encryptType == "all" {

randomKey := RandStringRunes(16)
cert, err := Dao.GetCert(version, "client") // 此处是从数据库读取certs, 也可以本地读取文件
if err != nil {
common.Log.Errorf("GetCert err: %s", err)
return
}

key, err := RsaEncryptData(cert.PublicKey, randomKey)
if err != nil {
common.Log.Errorf("RsaEncryptData err: %s", err)
return
}
encryptedData, err := AesEncryptData(randomKey, encryptWriter.Buff.String())
if err != nil {
common.Log.Errorf("AesEncryptData err: %s", err)
return
}

data, err := json.Marshal(EncryptParam{Key: key, EncryptedData: encryptedData})
if err != nil {
common.Log.Error(err.Error())
} else {
common.Log.Infof("%v-middlewares-encrypt raw: %v", c.Request.URL.Path, encryptWriter.Buff.String())
encryptWriter.Header().Set("bb-encrypt-ver", "1")
if _, err := encryptWriter.ResponseWriter.Write(data); err != nil {
common.Log.Error(err.Error())
}
}
} else {
normalReturn()
return
}
}

}

// RSA加密
func RsaEncryptData(publicKey, data string) (res string, err error) {
pk, err := encrypt.BytesToPublicKey([]byte(publicKey))
if err != nil {
return
}

eData, err := encrypt.EncryptWithPublicKey([]byte(data), pk)
if err != nil {
return
}

res = base64.StdEncoding.EncodeToString(eData)
return
}

// RSA解密
func RsaDecryptData(privateKey, data string) (res string, err error) {
eData, err := base64.StdEncoding.DecodeString(data)
if err != nil {
return
}

pk, err := encrypt.BytesToPrivateKey([]byte(privateKey))
if err != nil {
return
}

context, err := encrypt.DecryptWithPrivateKey(eData, pk)
if err != nil {
return
}
res = string(context)
return
}

// AES加密
func AesEncryptData(key, data string) (res string, err error) {
eData := encrypt.AesEncryptECB([]byte(data), []byte(key))
res = base64.URLEncoding.EncodeToString(eData)
return
}

// AES解密
func AesDecryptData(key, data string) (res string, err error) {
eData, err := base64.URLEncoding.DecodeString(data)
if err != nil {
return
}
context := encrypt.AesDecryptECB(eData, []byte(key))
res = string(context)
return
}

var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")

// 随机字符串
func RandStringRunes(n int) string {
b := make([]rune, n)
for i := range b {
b[i] = letterRunes[rand.Intn(len(letterRunes))]
}
return string(b)
}

2. 参考资料

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