(PHP 4 >= 4.0.4, PHP 5, PHP 7)
openssl_sign — Generate signature
$data
, string &$signature
, mixed $priv_key_id
[, mixed $signature_alg = OPENSSL_ALGO_SHA1
] ) : bool
openssl_sign() computes a signature for the
specified data by generating a cryptographic
digital signature using the private key associated with
priv_key_id. Note that the data itself is
not encrypted.
dataThe string of data you wish to sign
signature
If the call was successful the signature is returned in
signature.
priv_key_idresource - a key, returned by openssl_get_privatekey()
string - a PEM formatted key
signature_algint - one of these Signature Algorithms.
string - a valid string returned by openssl_get_md_methods() example, "sha256WithRSAEncryption" or "sha384".
Returns TRUE on success or FALSE on failure.
Example #1 openssl_sign() example
<?php
// $data is assumed to contain the data to be signed
// fetch private key from file and ready it
$pkeyid = openssl_pkey_get_private("file://src/openssl-0.9.6/demos/sign/key.pem");
// compute signature
openssl_sign($data, $signature, $pkeyid);
// free the key from memory
openssl_free_key($pkeyid);
?>
Example #2 openssl_sign() example
<?php
//data you want to sign
$data = 'my data';
//create new private and public key
$new_key_pair = openssl_pkey_new(array(
"private_key_bits" => 2048,
"private_key_type" => OPENSSL_KEYTYPE_RSA,
));
openssl_pkey_export($new_key_pair, $private_key_pem);
$details = openssl_pkey_get_details($new_key_pair);
$public_key_pem = $details['key'];
//create signature
openssl_sign($data, $signature, $private_key_pem, OPENSSL_ALGO_SHA256);
//save for later
file_put_contents('private_key.pem', $private_key_pem);
file_put_contents('public_key.pem', $public_key_pem);
file_put_contents('signature.dat', $signature);
//verify signature
$r = openssl_verify($data, $signature, $public_key_pem, "sha256WithRSAEncryption");
var_dump($r);
?>