从PHP到Mcrypt

Question

Im using a class to encrypt/decrypt strings in PHP.

How could I encrypt/decrypt the strings in Go?

The PHP class:

class Crypto {
    private $encryptKey = 'xxxxxxxxxxxxxxxx';
    private $iv = 'xxxxxxxxxxxxxxxx';
    private $blocksize = 16;
    public function decrypt($data)
    {
        return $this->unpad(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, 
            $this->encryptKey, 
            hex2bin($data),
            MCRYPT_MODE_CBC, $this->iv), $this->blocksize);
    }
    public function encrypt($data)
    {
        //don't use default php padding which is '\0'
        $pad = $this->blocksize - (strlen($data) % $this->blocksize);
        $data = $data . str_repeat(chr($pad), $pad);
        return bin2hex(mcrypt_encrypt(MCRYPT_RIJNDAEL_128,
            $this->encryptKey,
            $data, MCRYPT_MODE_CBC, $this->iv));
    }
    private function unpad($str, $blocksize)
    {
        $len = strlen($str);
        $pad = ord($str[$len - 1]);
        if ($pad && $pad <= $blocksize) {
            if (substr($str, -$pad) === str_repeat(chr($pad), $pad)) {
                return substr($str, 0, $len - $pad);
            }
        }
        return $str;
    }
}

What to be able to encrypt/decrypt same string in both PHP and Go.

Answer 1

Here is an example:

package main

import (
    "crypto/aes"
    "crypto/cipher"
    "crypto/rand"
    "encoding/base64"
    "errors"
    "fmt"
    "io"
    "log"
)

func main() {
    key := []byte("xxxxxxxxxxxxxxxx") // 32 bytes
    plaintext := []byte("TEST")
    fmt.Printf("%s
", plaintext)
    ciphertext, err := encrypt(key, plaintext)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%0x
", ciphertext)
    result, err := decrypt(key, ciphertext)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s
", 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(b))
    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(b))
    return ciphertext, nil
}

func decrypt(key, text []byte) ([]byte, error) {
    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)
    data, err := base64.StdEncoding.DecodeString(string(text))
    if err != nil {
        return nil, err
    }
    return data, nil
}

Mostly borrowed and adapted from: https://golang.org/src/crypto/cipher/example_test.go

// Input => TEST
// Output => 13360adba03733e11dd2702de441ff8bbb90676ad762fc83

UPDATE

To use a string as a parameter for decode function, you need to convert the string to byte using hex.Decodestring

data, _ := hex.DecodeString("1d6f12d3aa2353b23c6012dbc85816632129363d58a76063")
result, err := decrypt(key, data)
if err != nil {
    log.Fatal(err)
}
fmt.Printf("%s
", result)

Do not forget to include "encoding/hex" into package list.