Seal (encrypt) data

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- PHP Manual
- OpenSSL Functions
- Seal (encrypt) data

# openssl_seal

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

openssl_seal — Seal (encrypt) data

### Description

openssl_seal(
string `$data`,
string `&$sealed_data`,
array `&$encrypted_keys`,
array `$public_key`,
string `$cipher_algo`,
string `&$iv` = `null`
): int|false

openssl_seal() seals (encrypts) `data` by using the given `cipher_algo` with a randomly generated secret key. The key is encrypted with each of the public keys associated with the identifiers in `public_key` and each encrypted key is returned in `encrypted_keys`. This means that one can send sealed data to multiple recipients (provided one has obtained their public keys). Each recipient must receive both the sealed data and the envelope key that was encrypted with the recipient's public key.

### Parameters

`data`

  The data to seal.

`sealed_data`

  The sealed data.

`encrypted_keys`

  Array of encrypted keys.

`public_key`

  Array of OpenSSLAsymmetricKey instances containing public keys.

`cipher_algo`

  The cipher method.

  Caution

  The default value (`'RC4'`) is considered insecure. It is strongly recommended to explicitly specify a secure cipher method.

`iv`

  The initialization vector.

### Return Values

Returns the length of the sealed data on success, or `false` on error. If successful the sealed data is returned in `sealed_data`, and the envelope keys in `encrypted_keys`.

### Changelog

Version | Description
--- | ---
8.0.0 | `public_key` accepts an array of OpenSSLAsymmetricKey instances now; previously, an array of resources of type `OpenSSL key` was accepted.
8.0.0 | `cipher_algo` is no longer an optional parameter.
8.0.0 | `iv` is nullable now.

### Examples

Example #1 openssl_seal() example

    <?php// $data is assumed to contain the data to be sealed// fetch public keys for our recipients, and ready them$fp = fopen("/src/openssl-0.9.6/demos/maurice/cert.pem", "r");$cert = fread($fp, 8192);fclose($fp);$pk1 = openssl_get_publickey($cert);// Repeat for second recipient$fp = fopen("/src/openssl-0.9.6/demos/sign/cert.pem", "r");$cert = fread($fp, 8192);fclose($fp);$pk2 = openssl_get_publickey($cert);// seal message, only owners of $pk1 and $pk2 can decrypt $sealed with keys// $ekeys[0] and $ekeys[1] respectively.openssl_seal($data, $sealed, $ekeys, array($pk1, $pk2));// free the keys from memoryopenssl_free_key($pk1);openssl_free_key($pk2);?>

### See Also

- openssl_open() - Open sealed data