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This document uses PHP Chinese website manual Release
(PHP 4 >= 4.0.4, PHP 5)
openssl_sign — Generate signature
$data
, string &$signature
, mixed $priv_key_id
[, mixed $signature_alg
= OPENSSL_ALGO_SHA1
] ) 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.
data
The string of data you wish to sign
signature
If the call was successful the signature is returned in
signature
.
priv_key_id
resource - a key, returned by openssl_get_privatekey()
string - a PEM formatted key
signature_alg
int - one of these Signature Algorithms.
string - a valid string returned by openssl_get_md_methods() example, "sha256WithRSAEncryption" or "sha384".
成功时返回 TRUE
, 或者在失败时返回 FALSE
。
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 );
?>
[#1] Chris Kistner [2010-07-20 05:53:20]
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);
?>
[#2] edmarw at yahoo dot com [2007-09-04 09:22:37]
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";
}
?>
[#3] adam dot mansfeld at gmail dot com [2005-10-19 00:50:56]
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