(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
openssl_sign — Erzeugt eine Signatur
$data,&$signature,$private_key,$algorithm = OPENSSL_ALGO_SHA1
Die Funktion openssl_sign() errechnet die Signatur für
die im Parameter data angegebenen Daten, indem sie
unter Verwendung des privaten Schlüssels private_key
eine kryptographische digitale Signatur erzeugt. Es ist zu beachten, dass
die Daten selbst nicht verschlüsselt werden.
dataDie zu verschlüsselnden Daten.
signature
Nach erfolgreicher Ausführung wird die Signatur im Parameter
signature zurückgegeben.
private_keyOpenSSLAsymmetricKey - ein von openssl_get_privatekey() zurückgegebener Schlüssel.
string - ein Schlüssel im PEM-Format.
algorithmint - einer dieser Signatur-Algorithmen.
string - eine von openssl_get_md_methods() zurückgegebene gültige Zeichenkette, beispielsweise "sha256WithRSAEncryption" oder "sha384".
| Version | Beschreibung |
|---|---|
| 8.0.0 |
private_key akzeptiert nun eine
OpenSSLAsymmetricKey- oder
OpenSSLCertificate-Instanz; vorher wurde eine
Ressource vom Typ OpenSSL-Schlüssel oder
OpenSSL X.509 akzeptiert.
|
Beispiel #1 openssl_sign()-Beispiel
<?php
// Annahme: $data enthält die Daten, die signiert werden sollen
// holen und vorbereiten des privaten Schlüssels aus einer Datei
$pkeyid = openssl_pkey_get_private("file://src/openssl-0.9.6/demos/sign/key.pem");
// errechnen der Signatur
openssl_sign($data, $signature, $pkeyid);
// löschen des Schlüssels aus dem Speicher
openssl_free_key($pkeyid);
?>Beispiel #2 openssl_sign()-Beispiel
<?php
// die zu verschlüssenlnden Daten
$data = 'my data';
// erzeuge einen neuen privaten und öffentlichen Schlüssel
$new_key_pair = openssl_pkey_new(array(
"private_key_bits" => 2048,
"private_key_type" => OPENSSL_KEYTYPE_RSA,
));
openssl_pkey_export($new_key_pair, $private_key_pem);
$details = openssl_pkey_get_details($new_key_pair);
$public_key_pem = $details['key'];
// erzeuge die Signatur
openssl_sign($data, $signature, $private_key_pem, OPENSSL_ALGO_SHA256);
// für spätere Verwendung speichern
file_put_contents('private_key.pem', $private_key_pem);
file_put_contents('public_key.pem', $public_key_pem);
file_put_contents('signature.dat', $signature);
// Signatur überprüfen
$r = openssl_verify($data, $signature, $public_key_pem, "sha256WithRSAEncryption");
var_dump($r);
?>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.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";
}
?>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);
?>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