go aes对称加解密

package main

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"fmt"
)

const (
	key = "2018201820182018"
	iv  = "1234567887654321"
)

func main() {
	str := "abcd"
	es, _ := AesEncrypt(str, []byte(key))
	fmt.Println(es) // 8lCuwh5+vZrZmU1J9c9Alw==

	ds, _ := AesDecrypt(es, []byte(key))
	fmt.Println(string(ds))

}

func AesEncrypt(encodeStr string, key []byte) (string, error) {
	encodeBytes := []byte(encodeStr)
	//根据key 生成密文
	block, err := aes.NewCipher(key)
	if err != nil {
		return "", err
	}

	blockSize := block.BlockSize()
	encodeBytes = PKCS5Padding(encodeBytes, blockSize)

	blockMode := cipher.NewCBCEncrypter(block, []byte(iv))
	crypted := make([]byte, len(encodeBytes))
	blockMode.CryptBlocks(crypted, encodeBytes)

	return base64.StdEncoding.EncodeToString(crypted), nil
}

func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	//填充
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)

	return append(ciphertext, padtext...)
}

func AesDecrypt(decodeStr string, key []byte) ([]byte, error) {
	//先解密base64
	decodeBytes, err := base64.StdEncoding.DecodeString(decodeStr)
	if err != nil {
		return nil, err
	}
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	blockMode := cipher.NewCBCDecrypter(block, []byte(iv))
	origData := make([]byte, len(decodeBytes))

	blockMode.CryptBlocks(origData, decodeBytes)
	origData = PKCS5UnPadding(origData)
	return origData, nil
}

func PKCS5UnPadding(origData []byte) []byte {
	length := len(origData)
	unpadding := int(origData[length-1])
	return origData[:(length - unpadding)]
}