PHP 5.5.20 is available

openssl_seal

(PHP 4 >= 4.0.4, PHP 5)

openssl_sealSeal (encrypt) data

Description

int openssl_seal ( string $data , string &$sealed_data , array &$env_keys , array $pub_key_ids [, string $method ] )

openssl_seal() seals (encrypts) data by using RC4 with a randomly generated secret key. The key is encrypted with each of the public keys associated with the identifiers in pub_key_ids and each encrypted key is returned in env_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

sealed_data

env_keys

pub_key_ids

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 env_keys.

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");
$cert fread($fp8192);
fclose($fp);
$pk1 openssl_get_publickey($cert);
// Repeat for second recipient
$fp fopen("/src/openssl-0.9.6/demos/sign/cert.pem""r");
$cert fread($fp8192);
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 memory
openssl_free_key($pk1);
openssl_free_key($pk2);
?>

See Also

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User Contributed Notes 3 notes

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2
devel@no-spam
9 years ago
"seals (encrypts) data by using RC4 with a randomly generated secret key"
It should be noted that the randomly generated secret key is 128 bits long (openssl: EVP_rc4(void):  RC4 stream cipher. This is a variable key length cipher with default key length 128 bits.)
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0
omnibus at omnibus dot edu dot pl
5 years ago
Note that openssl_seal() causes Internal Server Error if $data is an empty string.
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0
hfuecks at nospam dot org
7 years ago
openssl_seal() can work well when you need to pass data securely to other platforms / languages. What openssl_seal() does is;

1. Generate a random key
2. Encrypt the data symmetrically with RC4 using the random key
3. Encrypt the random key itself with RSA using the public key / certificate
4. Returns the encrypted data and the encrypted key

So to decrypt the steps are simply;

1. Decrypt the key using RSA and your private key
2. Decrypt the data using RC4 and the decrypted key

The trickiest part may be figuring out how handle the private key - BouncyCastle ( http://www.bouncycastle.org/ ) provides a PEMReader for Java and C# while Not Yet commons-ssl ( http://juliusdavies.ca/commons-ssl/ ) has a KeyStoreBuilder to build Java keystores out of a PEM certificate.

A complete example in Java is described at http://blog.local.ch/archive/2007/10/29/openssl-php-to-java.html
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