utils/encoding/encoding.go

package utils

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

func AESEncrypt(originData string, key string) (string, error) {
	keyBytes := []byte(key)

	block, err := aes.NewCipher(keyBytes)
	if err != nil {
		return "", err
	}

	originDataBytes := []byte(originData)
	blockSize := block.BlockSize()
	originDataBytes = pkcs7Padding(originDataBytes, blockSize)
	blockMode := cipher.NewCBCEncrypter(block, keyBytes[:blockSize])
	encrypted := make([]byte, len(originDataBytes))
	blockMode.CryptBlocks(encrypted, originDataBytes)

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

func AESDecrypt(encrypted string, key string) (string, error) {
	keyBytes := []byte(key)

	block, err := aes.NewCipher(keyBytes)
	if err != nil {
		return "", err
	}

	decoded, err := base64.StdEncoding.DecodeString(encrypted)
	if err != nil {
		return "", err
	}

	blockSize := block.BlockSize()
	blockMode := cipher.NewCBCDecrypter(block, keyBytes[:blockSize])
	originData := make([]byte, len(decoded))
	blockMode.CryptBlocks(originData, decoded)
	originData = pkcs7UnPadding(originData)

	return string(originData), nil
}

func pkcs7Padding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padText := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padText...)
}

func pkcs7UnPadding(originData []byte) []byte {
	length := len(originData)
	unPadding := int(originData[length-1])
	return originData[:(length - unPadding)]
}