PHP random_bytes with sodium integer error

user_2025681 0
Viewed 6440

I am attempting to encrypt a string using random bytes and sodium in PHP 7.2.7 for IIS.

$nonce = random_bytes('SODIUM_CRYPTO_SECRETBOX_NONCEBYTES');

and

$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);

both return this error:

Uncaught TypeError: random_bytes() expects parameter 1 to be integer

however this works fine

$key = random_bytes('SODIUM_CRYPTO_SECRETBOX_KEYBYTES');

Google seems to be failing me with this one, I have found no help when searching.

php
3 Answers

Updated

Depending on how you have your PHP configured. You may not be accessing the constant correctly.

Please run this script and see if it helps your problem. Let me know what the results are.

$extenstion = FALSE;
$constants = FALSE;

echo '<pre>';

if(in_array('libsodium', get_loaded_extensions())){

  $extenstion = TRUE;
  echo 'Libsodium IS installed.<br>';

}else{

  echo 'Libsodium IS NOT installed.<br>';

  }

$constantsArray = get_defined_constants(true);

if(isset($constantsArray['libsodium']) && $constantsArray['libsodium']){

  $constants = TRUE;

  echo 'You HAVE predefined Libsodium constants.<br>';

}else{

  echo 'You DO NOT have any predefined Libsodium constants.<br>';

}

if($extenstion === TRUE && $constants === TRUE){

  foreach($constantsArray['libsodium'] as $constant=>$value){

    if(preg_match('/CRYPTO_SECRETBOX_NONCEBYTES|CRYPTO_SECRETBOX_KEYBYTES/', $constant)){

      echo 'Your predefined constant\'s name is set as this: ' . $constant . ' To use in your functions: random_bytes(' . $constant . ');' .  '<br>';

    }

  }    

echo 'Here is a full list of your Libsodium constants:<br>';
print_r(get_defined_constants(true)['libsodium']);

}

//***Leave these commented out when you first run the test.***

//To see ALL of your constants uncomment this line:
//print_r(get_defined_constants(true));

//To see ALL of your extensions uncomment this line:
//print_r(get_loaded_extensions());

echo '</pre>';
user_36353300

Excerpt this article:

Sodium (and NaCl) is an “opinionated” library: this means the algorithms used have been selected and cannot be changed. The library uses some of the most robust algorithms available, including Elliptic-curve cryptography (ECC).

And random_bytes() is not used to encrypt messages, this function only generates random bytecodes.

This sample code is to generate keys using Sodium:

$msg = 'This is a super secret message!';

// Generating an encryption key and a nonce
$key   = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES); // 256 bit
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES); // 24 bytes

// Encrypt
$ciphertext = sodium_crypto_secretbox($msg, $nonce, $key);
// Decrypt
$plaintext = sodium_crypto_secretbox_open($ciphertext, $nonce, $key);

echo $plaintext === $msg ? 'Success' : 'Error';

See? SODIUM_CRYPTO_SECRETBOX_NONCEBYTES is actually a predefined constant, which is the length of the key. Follow this document for other predefined constants.

user_75216860

Your second implementation

$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);

Should work if you have the extension installed and properly configured. I would look into that if I were you.

You can check your PHP's configuration using phpinfo() to check if the sodium is enabled.

And, If you haven't installed, install using:

sudo pecl install -f libsodium
user_2952640
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