3DES Encryption

3des.go

package _3DES

import (
	"bytes"
	"crypto/cipher"
	"crypto/des"
)

// Encrypt using 3DES
func Encrypt(input, key []byte) ([]byte, error) {
	block, err := des.NewTripleDESCipher(key)
	if err != nil {
		return nil, err
	}

	bs := block.BlockSize()
	iv := make([]byte, bs)

	padding := bs - len(input)%bs
	paddedInput := append(input, bytes.Repeat([]byte{byte(padding)}, padding)...)
	cipherInput := make([]byte, len(paddedInput))

	mode := cipher.NewCBCEncrypter(block, iv)
	mode.CryptBlocks(cipherInput, paddedInput)

	return cipherInput, nil
}

// Decrypt using 3DES
func Decrypt(input, key []byte) ([]byte, error) {
	block, err := des.NewTripleDESCipher(key)
	if err != nil {
		return nil, err
	}

	iv := make([]byte, block.BlockSize())
	mode := cipher.NewCBCDecrypter(block, iv)

	paddedInput := make([]byte, len(input))
	mode.CryptBlocks(paddedInput, input)

	padding := paddedInput[len(paddedInput)-1]
	decrypted := paddedInput[:len(paddedInput)-int(padding)]

	return decrypted, nil
}