golang 的AES加解密 CBC/ECB/CFB 模式

golang的AES加密和解密的三种模式实现（CBC/ECB/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,base64.StdEncoding.EncodetoString(encrypted))
	decrypted = AesDecryptECB(encrypted,string(decrypted))

	log.Println("------------------ CFB模式 --------------------")
	encrypted = AesEncryptCFB(origData,base64.StdEncoding.EncodetoString(encrypted))
	decrypted = AesDecryptCFB(encrypted,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,cipher.BlockSize(); bs < len(encrypted); bs,be+cipher.BlockSize() {
		cipher.Decrypt(decrypted[bs:be],encrypted[bs:be])
	}

	bEnd := SearchByteSliceIndex(decrypted,0)

	return decrypted[:bEnd]
}
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
}

// []byte 字节切片 循环查找
func SearchByteSliceIndex(bSrc []byte,b byte) int {
	for i := 0; i < len(bSrc); i++ {
		if bSrc[i] == b {
			return i
		}
	}

	return -1
}

// =================== 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,_ := 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
}

输出结果：