openssl_sign
PHP function
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(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
Generate signature
Description
openssl_sign(string $data, string $signature, OpenSSLAsymmetricKey|OpenSSLCertificate|array|string $private_key, string|int $algorithm = OPENSSL_ALGO_SHA1, int $padding = 0): bool
openssl_sign() computes a signature for the specified data by generating a cryptographic digital signature using the private key associated with private_key. Note that the data itself is not encrypted.
Parameters
dataThe string of data you wish to sign
signatureIf the call was successful the signature is returned in
signature.private_keyOpenSSLAsymmetricKey- a key, returned byopenssl_get_privatekey()string- a PEM formatted keyalgorithmint- one of these Signature Algorithms.string- a valid string returned byopenssl_get_md_methods()example, "sha256WithRSAEncryption" or "sha384".paddingRSA-PSS padding to use. It can be either
OPENSSL_PKCS1_PADDING,OPENSSL_PKCS1_PSS_PADDING, or0.
Return Values
Success
Changelog
| Version | Description |
|---|---|
| 8.5.0 | The optional parameter padding has been added. |
| 8.0.0 | private_key accepts an OpenSSLAsymmetricKey or OpenSSLCertificate instance now; previously, a Resource of type OpenSSL key or OpenSSL X.509 was accepted. |
Examples
openssl_sign() example
php
<?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);
?>openssl_sign() example
php
<?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);
?>