AES encryption with Go and PHP - php

Question

I am using AES encryption in Go and PHP. But both the languages does not encrypt/decrypt each other ciphertext. Following i have tried in php
class Crypto {
private $encryptKey = "keyforencryption";
private $iv = 'ivusedforencrypt';
private $blocksize = 16;
public function encrypt($toEncrypt){
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CFB);
//$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
return base64_encode($this->iv . mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->encryptKey, $toEncrypt, MCRYPT_MODE_CFB, $this->iv));
}
public function decrypt($toDecrypt){
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CFB);//$this->blocksize;
$toDecrypt = base64_decode($toDecrypt);
return rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->encryptKey, substr($toDecrypt, $iv_size), MCRYPT_MODE_CFB, substr($toDecrypt, 0, $iv_size)));
}
}
$c = new Crypto();
echo "Encrypted : ".$e = $c->encrypt("test");
echo "<br/>Decrypted : ".$c->decrypt($e);
output : aXZ1c2VkZm9yZW5jcnlwdDpdZEinU2rB
and this one in Go with AES
package main
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"errors"
"fmt"
"io"
"log"
)
func main() {
key := []byte("keyforencryption")
plaintext := []byte("test")
fmt.Printf("%s\n", plaintext)
ciphertext, err := encrypt(key, plaintext)
if err != nil {
log.Fatal(err)
}
b := base64.StdEncoding.EncodeToString(ciphertext)
fmt.Printf("Encrypted text : %s\n", b)
result, err := decrypt(key, b)
if err != nil {
log.Fatal(err)
}
fmt.Printf("Decrypted Text : %s\n", result)
}
func encrypt(key, text []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
//b := base64.StdEncoding.EncodeToString(text)
ciphertext := make([]byte, aes.BlockSize+len(text))
iv := ciphertext[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
return nil, err
}
cfb := cipher.NewCFBEncrypter(block, iv)
cfb.XORKeyStream(ciphertext[aes.BlockSize:], []byte(text))
return ciphertext, nil
}
func decrypt(key []byte, text1 string) ([]byte, error) {
text, _ := base64.StdEncoding.DecodeString(string(text1))
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
if len(text) < aes.BlockSize {
return nil, errors.New("ciphertext too short")
}
iv := text[:aes.BlockSize]
text = text[aes.BlockSize:]
cfb := cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(text, text)
b := base64.StdEncoding.EncodeToString(text)
data, err := base64.StdEncoding.DecodeString(string(b))
if err != nil {
return nil, err
}
return data, nil
}
output : ZVnhCXjIvtGKBdqvjwHRZKcVy34=
any help would be appreciable.

Answer 1

CFB mode has an issue, this will work in CBC mode
class Crypto {
private $encryptKey = "keyforencryption";
public function encrypt($toEncrypt){
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
return base64_encode($iv . mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->encryptKey, $toEncrypt, MCRYPT_MODE_CBC, $iv));
}
public function decrypt($toDecrypt){
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
echo "<br/>".$toDecrypt = base64_decode($toDecrypt);
return rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->encryptKey, substr($toDecrypt, $iv_size), MCRYPT_MODE_CBC, substr($toDecrypt, 0, $iv_size)));
}
}
$c = new Crypto();
echo "Encrypted : ".$e = $c->encrypt("test123");
echo "<br/>Decrypted : ".$c->decrypt($e);
and this one in golang
package main
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"fmt"
"io"
"bytes"
)
func main() {
e:= cbcEncrypt()
fmt.Printf("Encrypted String : %s\n", e)
d:= cbcDecrypt(e)
fmt.Printf("Decrypted String : %s\n", d)
}
func cbcDecrypt(text1 string) []byte{
key := []byte("keyforencryption")
ciphertext, _ := base64.StdEncoding.DecodeString(string(text1))
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
// include it at the beginning of the ciphertext.
if len(ciphertext) < aes.BlockSize {
panic("ciphertext too short")
}
iv := ciphertext[:aes.BlockSize]
ciphertext = ciphertext[aes.BlockSize:]
// CBC mode always works in whole blocks.
if len(ciphertext)%aes.BlockSize != 0 {
panic("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(ciphertext, ciphertext)
ciphertext = PKCS5UnPadding(ciphertext)
return ciphertext
}
func cbcEncrypt() string{
key := []byte("keyforencryption")
plaintext := []byte("testssssss")
plaintext = PKCS5Padding(plaintext, 16)
// CBC mode works on blocks so plaintexts may need to be padded to the
// next whole block. For an example of such padding, see
// https://tools.ietf.org/html/rfc5246#section-6.2.3.2. Here we'll
// assume that the plaintext is already of the correct length.
if len(plaintext)%aes.BlockSize != 0 {
panic("plaintext is not a multiple of the block size")
}
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
// The IV needs to be unique, but not secure. Therefore it's common to
// include it at the beginning of the ciphertext.
ciphertext := make([]byte, aes.BlockSize+len(plaintext))
iv := ciphertext[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
panic(err)
}
mode := cipher.NewCBCEncrypter(block, iv)
mode.CryptBlocks(ciphertext[aes.BlockSize:], plaintext)
// It's important to remember that ciphertexts must be authenticated
// (i.e. by using crypto/hmac) as well as being encrypted in order to
// be secure.
return base64.StdEncoding.EncodeToString(ciphertext)
}
func PKCS5Padding(src []byte, blockSize int) []byte {
padding := blockSize - len(src)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(src, padtext...)
}
func PKCS5UnPadding(src []byte) []byte {
length := len(src)
unpadding := int(src[length-1])
return src[:(length - unpadding)]
}
this should work

Answer 2

Also use padding for encoding and unpadding for decode in php.
function pkcs5_pad($text)
{
$blocksize = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$pad = $blocksize - (strlen($text) % $blocksize);
return $text . str_repeat(chr($pad), $pad);
}
function pkcs5_unpad($text)
{
$block = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$pad = ord($text[($len = strlen($text)) - 1]);
$len = strlen($text);
$pad = ord($text[$len-1]);
return substr($text, 0, strlen($text) - $pad);
}