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openssl_open

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

openssl_open — Open sealed data

Description

function openssl_open(
    string $data,
    #[\SensitiveParameter]string &$output,
    string $encrypted_key,
    #[\SensitiveParameter]OpenSSLAsymmetricKey|OpenSSLCertificate|array|string $private_key,
    string $cipher_algo,
    ?string $iv = null
): bool

openssl_open() opens (decrypts) data using an envelope key that is decrypted from encrypted_key using private_key. The decryption is done using cipher_algo and iv. The IV is required only if the cipher method requires it. The function fills output with the decrypted data. The envelope key is usually generated when the data are sealed using a public key that is associated with the private key. See openssl_seal() for more information.

Parameters

data

The sealed data.

output

If the call is successful the opened data is returned in this parameter.

encrypted_key

The encrypted symmetric key that can be decrypted using private_key.

private_key

The private key used for decrypting encrypted_key.

cipher_algo

The cipher method used for decryption of data.

Caution

The default value for PHP versions prior to 8.0 is ('RC4') which is considered insecure. It is strongly recommended to explicitly specify a secure cipher method.

iv

The initialization vector used for decryption of data. It is required if the cipher method requires IV. This can be found out by calling openssl_cipher_iv_length() with cipher_algo.

Return Values

Returns true on success or false on failure.

Changelog

Version	Description
8.0.0	`private_key` accepts an OpenSSLAsymmetricKey or OpenSSLCertificate instance now; previously, a resource of type `OpenSSL key` or `OpenSSL X.509 CSR` was accepted.
8.0.0	`cipher_algo` is no longer an optional parameter.

Examples

Example #1 openssl_open() example

<?php

// $sealed, $env_key and $iv are assumed to contain the sealed data, our
// envelope key and IV. All given to us by the sealer.

// Fetch private key from file located in private_key.pem
$pkey = openssl_get_privatekey("file://private_key.pem");

// Decrypt the data and store it in $open
if (openssl_open($sealed, $open, $env_key, $pkey, 'AES256', $iv)) {
    echo "Here is the opened data: ", $open;
} else {
    echo "Failed to open data";
}

?>

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User Contributed Notes 2 notes

down

sdc ¶

15 years ago

PHP compiled without OpenSSL support? Here's how you can call the openssl command-line utility to achieve the same goal:

<?php
// $sealed and $env_key are assumed to contain the sealed data
// and our envelope key, both given to us by the sealer.

// specify private key file and passphrase
$pkey_file='key.pem';
$pkey_pp='netsvc';

// call openssl to decrypt envelope key
$ph=proc_open('openssl rsautl -decrypt -inkey '.
 escapeshellarg($pkey_file).' -passin fd:3',array(
  0 => array('pipe','r'), // stdin < envelope key
  1 => array('pipe','w'), // stdout > decoded envelope key
  2 => STDERR,
  3 => array('pipe','r'), // < passphrase
 ),$pipes);
// write envelope key
fwrite($pipes[0],$env_key);
fclose($pipes[0]);
// write private key passphrase
fwrite($pipes[3],$pkey_pp);
fclose($pipes[3]);
// read decoded key, convert to hexadecimal
$env_key='';
while(!feof($pipes[1])){
  $env_key.=sprintf("%02x",ord(fgetc($pipes[1])));
}
fclose($pipes[1]);
if($xc=proc_close($ph)){
  echo "Exit code: $xc\n";
}

// call openssl to decryp
$ph=proc_open('openssl rc4 -d -iv 0 -K '.$env_key,array(
  0 => array('pipe','r'), // stdin < sealed data
  1 => array('pipe','w'), // stdout > opened data
  2 => STDERR,
 ),$pipes);
// write sealed data
fwrite($pipes[0],$sealed);
fclose($pipes[0]);
// read opened data
//$open=stream_get_contents($pipes[1]);
$open='';
while(!feof($pipes[1])){
  $open.=fgets($pipes[1]);
}
fclose($pipes[1]);
if($xc=proc_close($ph)){
  echo "Exit code: $xc\n";
}

// display the decrypted data
echo $open;

?>