11. crypto 加密

RSA 加密解密
package main

import (
“crypto/rand”
“crypto/rsa”
“crypto/x509”
“encoding/hex”
“encoding/pem”
“fmt”
“os”
)

//生成RSA私钥和公钥，保存到文件中
func GenerateRSAKey(bits int) {
//GenerateKey函数使用随机数据生成器random生成一对具有指定字位数的RSA密钥
//Reader是一个全局、共享的密码用强随机数生成器
privateKey, err := rsa.GenerateKey(rand.Reader, bits)
if err != nil {
panic(err)
}
//保存私钥
//通过x509标准将得到的ras私钥序列化为ASN.1 的 DER编码字符串
X509PrivateKey := x509.MarshalPKCS1PrivateKey(privateKey)
//使用pem格式对x509输出的内容进行编码
//创建文件保存私钥
privateFile, err := os.Create(“private.pem”)
if err != nil {
panic(err)
}
defer privateFile.Close()
//构建一个pem.Block结构体对象
privateBlock := pem.Block{Type: “RSA Private Key”, Bytes: X509PrivateKey}
//将数据保存到文件
pem.Encode(privateFile, &privateBlock)

//保存公钥
//获取公钥的数据
publicKey := privateKey.PublicKey
//X509对公钥编码
X509PublicKey, err := x509.MarshalPKIXPublicKey(&publicKey)
if err != nil {
panic(err)
}
//pem格式编码
//创建用于保存公钥的文件
publicFile, err := os.Create(“public.pem”)
if err != nil {
panic(err)
}
defer publicFile.Close()
//创建一个pem.Block结构体对象
publicBlock := pem.Block{Type: “RSA Public Key”, Bytes: X509PublicKey}
//保存到文件
pem.Encode(publicFile, &publicBlock)
}

//RSA加密
func RSAEncrypt(plainText []byte, path string) []byte {
//打开文件
file, err := os.Open(path)
if err != nil {
panic(err)
}
defer file.Close()
//读取文件的内容
info, := file.Stat()
buf := make([]byte, info.Size())
file.Read(buf)
//pem解码
block, _ := pem.Decode(buf)
//x509解码

publicKeyInterface, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
panic(err)
}
//类型断言
publicKey := publicKeyInterface.(*rsa.PublicKey)
//对明文进行加密
cipherText, err := rsa.EncryptPKCS1v15(rand.Reader, publicKey, plainText)
if err != nil {
panic(err)
}
//返回密文
return cipherText
}

//RSA解密
func RSADecrypt(cipherText []byte, path string) []byte {
//打开文件
file, err := os.Open(path)
if err != nil {
panic(err)
}
defer file.Close()
//获取文件内容
info, := file.Stat()
buf := make([]byte, info.Size())
file.Read(buf)
//pem解码
block, := pem.Decode(buf)
//X509解码
privateKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
panic(err)
}
//对密文进行解密
plainText, := rsa.DecryptPKCS1v15(rand.Reader, privateKey, cipherText)
//返回明文
return plainText
}
func main() {
//生成密钥对，保存到文件
GenerateRSAKey(2048)
message := []byte(“hello world”)
//加密
cipherText := RSA_Encrypt(message, “public.pem”)
fmt.Println(“加密后为：”, hex.EncodeToString(cipherText))
//解密
plainText := RSA_Decrypt(cipherText, “private.pem”)
fmt.Println(“解密后为：”, string(plainText))
}

Crypto AES加密 （ECB，CBC，CFB）
package main

import (
“bytes”
“crypto/aes”
“crypto/cipher”
“crypto/rand”
“encoding/base64”
“encoding/hex”
“io”
“log”
)

func main() {
origData := []byte(“Hello World”) // 待加密的数据
key := []byte(“ABCDEFGHIJKLMNOP”) // 加密的密钥
log.Println(“原文：”, string(origData))

log.Println(“————————— CBC模式 ——————————“)
encrypted := AesEncryptCBC(origData, key)
log.Println(“密文(hex)：”, hex.EncodeToString(encrypted))
log.Println(“密文(base64)：”, base64.StdEncoding.EncodeToString(encrypted))
decrypted := AesDecryptCBC(encrypted, key)
log.Println(“解密结果：”, string(decrypted))

log.Println(“————————— ECB模式 ——————————“)
encrypted = AesEncryptECB(origData, key)
log.Println(“密文(hex)：”, hex.EncodeToString(encrypted))
log.Println(“密文(base64)：”, base64.StdEncoding.EncodeToString(encrypted))
decrypted = AesDecryptECB(encrypted, key)
log.Println(“解密结果：”, string(decrypted))

log.Println(“————————— CFB模式 ——————————“)
encrypted = AesEncryptCFB(origData, key)
log.Println(“密文(hex)：”, hex.EncodeToString(encrypted))
log.Println(“密文(base64)：”, base64.StdEncoding.EncodeToString(encrypted))
decrypted = AesDecryptCFB(encrypted, key)
log.Println(“解密结果：”, string(decrypted))
}

// =================== 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) {
cipher, _ := 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, cipher.BlockSize(); bs <= len(origData); bs, be = bs+cipher.BlockSize(), be+cipher.BlockSize() {
cipher.Encrypt(encrypted[bs:be], plain[bs:be])
}

return encrypted
}
func AesDecryptECB(encrypted []byte, key []byte) (decrypted []byte) {
cipher, _ := aes.NewCipher(generateKey(key))
decrypted = make([]byte, len(encrypted))
//
for bs, be := 0, cipher.BlockSize(); bs < len(encrypted); bs, be = bs+cipher.BlockSize(), be+cipher.BlockSize() {
cipher.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
}

// =================== CFB ======================
func AesEncryptCFB(origData []byte, key []byte) (encrypted []byte) {
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
encrypted = make([]byte, aes.BlockSize+len(origData))
iv := encrypted[:aes.BlockSize]
if , err := io.ReadFull(rand.Reader, iv); err != nil {
panic(err)
}
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(encrypted[aes.BlockSize:], origData)
return encrypted
}
func AesDecryptCFB(encrypted []byte, key []byte) (decrypted []byte) {
block, := aes.NewCipher(key)
if len(encrypted) < aes.BlockSize {
panic(“ciphertext too short”)
}
iv := encrypted[:aes.BlockSize]
encrypted = encrypted[aes.BlockSize:]

stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(encrypted, encrypted)
return encrypted
}