openssl_sign

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

openssl_sign — Signe les données

Description

openssl_sign(
    string $data,
    string &$signature,
    OpenSSLAsymmetricKey|OpenSSLCertificate|array|string $private_key,
    string|int $algorithm = OPENSSL_ALGO_SHA1
): bool

openssl_sign() calcule la signature des données data en générant une signature digitale cryptographique en utilisant la clé privée associée avec le paramètre private_key. Notez que les données elles-mêmes ne sont pas chiffrées.

Liste de paramètres

data

La chaîne de données que vous souhaitez signer.

signature

Si l'appel à la fonction est un succès, la signature sera retournée dans le paramètre signature.

private_key

OpenSSLAsymmetricKey - une clé, retournée par la fonction openssl_get_privatekey()

string - une clé au format PEM.

algorithm

int - une des signatures d'algorithmes.

string - une chaîne valide retournée par la fonction openssl_get_md_methods(), par exemple : "sha256WithRSAEncryption" ou "sha384".

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Historique

Version	Description
8.0.0	`private_key` accepte désormais une instance de OpenSSLAsymmetricKey ou OpenSSLCertificate ; auparavant, une ressource de type `OpenSSL key` ou `OpenSSL X.509` était acceptée.

Exemples

Exemple #1 Exemple avec openssl_sign()

<?php
// On suppose que $data contient les données à signer

// lecture de la clé publique pour chaque destinataire
$pkeyid = openssl_pkey_get_private("file://src/openssl-0.9.6/demos/sign/key.pem");

// calcule de la signature
openssl_sign($data, $signature, $pkeyid);

// libère les clés de la mémoire
openssl_free_key($pkeyid);
?>

Exemple #2 Exemple avec openssl_sign()

<?php
//données que vous souhaitez signer
$data = 'my data';

//Crée une nouvelle clé privée et publique
$new_key_pair = openssl_pkey_new(array(
    "private_key_bits" => 2048,
    "private_key_type" => OPENSSL_KEYTYPE_RSA,
));
openssl_pkey_export($new_key_pair, $private_key_pem);

$details = openssl_pkey_get_details($new_key_pair);
$public_key_pem = $details['key'];

//Création de la signature
openssl_sign($data, $signature, $private_key_pem, OPENSSL_ALGO_SHA256);

//Sauvegarde pour utilisation ultérieur
file_put_contents('private_key.pem', $private_key_pem);
file_put_contents('public_key.pem', $public_key_pem);
file_put_contents('signature.dat', $signature);

//Vérification de la signature
$r = openssl_verify($data, $signature, $public_key_pem, "sha256WithRSAEncryption");
var_dump($r);
?>

Voir aussi

openssl_verify() - Vérifie une signature

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User Contributed Notes 4 notes

down

edmarw at yahoo dot com ¶

17 years ago


This may help if you just want a real-simple private/public key pair:

<?php

$data = "Beeeeer is really good.. hic...";

// You can get a simple private/public key pair using:
// openssl genrsa 512 >private_key.txt
// openssl rsa -pubout <private_key.txt >public_key.txt

// IMPORTANT: The key pair below is provided for testing only. 
// For security reasons you must get a new key pair
// for production use, obviously.

$private_key = <<<EOD
-----BEGIN RSA PRIVATE KEY-----
MIIBOgIBAAJBANDiE2+Xi/WnO+s120NiiJhNyIButVu6zxqlVzz0wy2j4kQVUC4Z
RZD80IY+4wIiX2YxKBZKGnd2TtPkcJ/ljkUCAwEAAQJAL151ZeMKHEU2c1qdRKS9
sTxCcc2pVwoAGVzRccNX16tfmCf8FjxuM3WmLdsPxYoHrwb1LFNxiNk1MXrxjH3R
6QIhAPB7edmcjH4bhMaJBztcbNE1VRCEi/bisAwiPPMq9/2nAiEA3lyc5+f6DEIJ
h1y6BWkdVULDSM+jpi1XiV/DevxuijMCIQCAEPGqHsF+4v7Jj+3HAgh9PU6otj2n
Y79nJtCYmvhoHwIgNDePaS4inApN7omp7WdXyhPZhBmulnGDYvEoGJN66d0CIHra
I2SvDkQ5CmrzkW5qPaE2oO7BSqAhRZxiYpZFb5CI
-----END RSA PRIVATE KEY-----
EOD;
$public_key = <<<EOD
-----BEGIN PUBLIC KEY-----
MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANDiE2+Xi/WnO+s120NiiJhNyIButVu6
zxqlVzz0wy2j4kQVUC4ZRZD80IY+4wIiX2YxKBZKGnd2TtPkcJ/ljkUCAwEAAQ==
-----END PUBLIC KEY-----
EOD;

$binary_signature = "";

// At least with PHP 5.2.2 / OpenSSL 0.9.8b (Fedora 7)
// there seems to be no need to call openssl_get_privatekey or similar.
// Just pass the key as defined above
openssl_sign($data, $binary_signature, $private_key, OPENSSL_ALGO_SHA1);

// Check signature
$ok = openssl_verify($data, $binary_signature, $public_key, OPENSSL_ALGO_SHA1);
echo "check #1: ";
if ($ok == 1) {
    echo "signature ok (as it should be)\n";
} elseif ($ok == 0) {
    echo "bad (there's something wrong)\n";
} else {
    echo "ugly, error checking signature\n";
}

$ok = openssl_verify('tampered'.$data, $binary_signature, $public_key, OPENSSL_ALGO_SHA1);
echo "check #2: ";
if ($ok == 1) {
    echo "ERROR: Data has been tampered, but signature is still valid! Argh!\n";
} elseif ($ok == 0) {
    echo "bad signature (as it should be, since data has beent tampered)\n";
} else {
    echo "ugly, error checking signature\n";
}

?>

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tim at remitone dot com ¶

1 year ago


It should be noted that the default signature algorithm used by openssl_sign() and openssl_verify (OPENSSL_ALGO_SHA1) is no longer supported by default in OpenSSL Version 3 series.

With an up to date OpenSSL library, one has to run
"update-crypto-policies --set LEGACY"
on the server where the library resides in order to allow these functions to work without the optional alternative algorithm argument.

down

-6

Chris Kistner ¶

14 years ago


The list of Signature Algorithms (constants) is very limited! Fortunately the newer versions of php/openssl allow you to specify the signature algorithm as a string.

You can use the 'openssl_get_md_methods' method to get a list of digest methods. Only some of them may be used to sign with RSA private keys.

Those that can be used to sign with RSA private keys are: md4, md5, ripemd160, sha, sha1, sha224, sha256, sha384, sha512

Here's the modified Example #1 with SHA-512 hash:
<?php
// $data is assumed to contain the data to be signed

// fetch private key from file and ready it
$fp = fopen("/src/openssl-0.9.6/demos/sign/key.pem", "r");
$priv_key = fread($fp, 8192);
fclose($fp);
$pkeyid = openssl_get_privatekey($priv_key);

// compute signature with SHA-512
openssl_sign($data, $signature, $pkeyid, "sha512");

// free the key from memory
openssl_free_key($pkeyid);
?>

down

-19

adam dot mansfeld at gmail dot com ¶

19 years ago


Hello,

the fourth parameter 'signature_alg' to choose the signature algorithm can be one of:

OPENSSL_ALGO_SHA1
OPENSSL_ALGO_MD5
OPENSSL_ALGO_MD4
OPENSSL_ALGO_MD2

Just for the case that somebody needs this.

Regards

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