AESUtil

AESUtil.go

package AESUtil

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

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

	return append(ciphertext, padtext...)
}

func PKCS5Trimming(encrypt []byte) []byte {
	padding := encrypt[len(encrypt)-1]
	return encrypt[:len(encrypt)-int(padding)]
}

func Encrypt(key []byte, text []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}
	text = PKCS5Padding(text, aes.BlockSize)
	ciphertext := make([]byte, len(text))

	cbc := cipher.NewCBCEncrypter(block, key)
	cbc.CryptBlocks(ciphertext, text)
	return ciphertext, nil
}

func Decrypt(key []byte, crypt []byte) []byte {
	block, err := aes.NewCipher(key)
	if err != nil {
		fmt.Println("key error1", err)
	}
	if len(crypt) == 0 {
		fmt.Println("plain content empty")
	}

	ecb := cipher.NewCBCDecrypter(block, key)
	decrypted := make([]byte, len(crypt))
	ecb.CryptBlocks(decrypted, crypt)

	return PKCS5Trimming(decrypted)
}