/DesEncrypt DES加密
//密钥必须是64位，所以key必须是长度为8的byte数组
func DesEncrypt(text string, key []byte) (string, error) {
	if len(key) != 8 {
		return "", fmt.Errorf("DES加密算法要求key必须是64位bit")
	}
	block, err := des.NewCipher(key) //用des创建一个加密器cipher
	if err != nil {
		return "", err
	}
	src := []byte(text)
	blockSize := block.BlockSize()           //分组的大小，blockSize=8
	src = common.ZeroPadding(src, blockSize) //填充成64位整倍数
	out := make([]byte, len(src)) //密文和明文的长度一致
	dst := out
	for len(src) > 0 {
		//分组加密
		block.Encrypt(dst, src[:blockSize]) //对src进行加密，加密结果放到dst里
		//移到下一组
		src = src[blockSize:]
		dst = dst[blockSize:]
	}
	return hex.EncodeToString(out), nil
}
//DesDecrypt DES解密
//密钥必须是64位，所以key必须是长度为8的byte数组
func DesDecrypt(text string, key []byte) (string, error) {
	src, err := hex.DecodeString(text) //转成[]byte
	if err != nil {
		return "", err
	}
	block, err := des.NewCipher(key)
	if err != nil {
		return "", err
	}
	blockSize := block.BlockSize()
	out := make([]byte, len(src))
	dst := out
	for len(src) > 0 {
		//分组解密
		block.Decrypt(dst, src[:blockSize])
		src = src[blockSize:]
		dst = dst[blockSize:]
	}
	out = common.ZeroUnPadding(out) //反填充
	return string(out), nil
}

func DesEncryptCBC(text string, key []byte) (string, error) {
	src := []byte(text)
	block, err := des.NewCipher(key) //用des创建一个加密器cipher
	if err != nil {
		return "", err
	}
	blockSize := block.BlockSize()           //分组的大小，blockSize=8
	src = common.ZeroPadding(src, blockSize) //填充
	out := make([]byte, len(src))                   //密文和明文的长度一致
	encrypter := cipher.NewCBCEncrypter(block, key) //CBC分组模式加密
	encrypter.CryptBlocks(out, src)
	return hex.EncodeToString(out), nil
}
func DesDecryptCBC(text string, key []byte) (string, error) {
	src, err := hex.DecodeString(text) //转成[]byte
	if err != nil {
		return "", err
	}
	block, err := des.NewCipher(key)
	if err != nil {
		return "", err
	}
	out := make([]byte, len(src))                   //密文和明文的长度一致
	encrypter := cipher.NewCBCDecrypter(block, key) //CBC分组模式解密
	encrypter.CryptBlocks(out, src)
	out = common.ZeroUnPadding(out) //反填充
	return string(out), nil
}

package main
import (
	"crypto/aes"
	"crypto/cipher"
	"fmt"
)
var commonIV = []byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f}
func encrypt(plainText string, keyText string) (cipherByte []byte, err error) {
	// 转换成字节数据, 方便加密
	plainByte := []byte(plainText)
	keyByte := []byte(keyText)
	// 创建加密算法aes
	c, err := aes.NewCipher(keyByte)
	if err != nil {
		return nil, err
	}
	//加密字符串
	cfb := cipher.NewCFBEncrypter(c, commonIV)
	cipherByte = make([]byte, len(plainByte))
	cfb.XORKeyStream(cipherByte, plainByte)
	return
}
func decrypt(cipherByte []byte, keyText string) (plainText string, err error) {
	// 转换成字节数据, 方便加密
	keyByte := []byte(keyText)
	// 创建加密算法aes
	c, err := aes.NewCipher(keyByte)
	if err != nil {
		return "", err
	}
	// 解密字符串
	cfbdec := cipher.NewCFBDecrypter(c, commonIV)
	plainByte := make([]byte, len(cipherByte))
	cfbdec.XORKeyStream(plainByte, cipherByte)
	plainText = string(plainByte)
	return
}
func main() {
	plain := "The text need to be encrypt."
	// AES 规定有3种长度的key: 16, 24, 32分别对应AES-128, AES-192, or AES-256
	key := "abcdefgehjhijkmlkjjwwoew"
	// 加密
	cipherByte, err := encrypt(plain, key)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Printf("%s ==> %x\n", plain, cipherByte)
	// 解密
	plainText, err := decrypt(cipherByte, key)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Printf("%x ==> %s\n", cipherByte, plainText)
}

// aesCBCEncrypt aes加密，填充秘钥key的16位，24,32分别对应AES-128, AES-192, or AES-256.
func aesCBCEncrypt(rawData, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	//填充原文
	blockSize := block.BlockSize()
	rawData = pkcs7Padding(rawData, blockSize)
	//初始向量IV必须是唯一，但不需要保密
	cipherText := make([]byte, blockSize+len(rawData))
	//block大小 16
	iv := cipherText[:blockSize]
	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
		return nil, err
	}
	//block大小和初始向量大小一定要一致
	mode := cipher.NewCBCEncrypter(block, iv)
	mode.CryptBlocks(cipherText[blockSize:], rawData)
	return cipherText, nil
}

func aesCBCDecrypt(encryptData, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	blockSize := block.BlockSize()
	if len(encryptData) < blockSize {
		return nil, errors.New("ciphertext too short")
	}
	iv := encryptData[:blockSize]
	encryptData = encryptData[blockSize:]
	// CBC mode always works in whole blocks.
	if len(encryptData)%blockSize != 0 {
		return nil, errors.New("ciphertext is not a multiple of the block size")
	}
	mode := cipher.NewCBCDecrypter(block, iv)
	// CryptBlocks can work in-place if the two arguments are the same.
	mode.CryptBlocks(encryptData, encryptData)
	//解填充
	encryptData = pkcs7UnPadding(encryptData)
	return encryptData, nil
}