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This document uses PHP Chinese website manual Release
(PHP 4 >= 4.0.4, PHP 5)
openssl_verify — Verify signature
$data
, string $signature
, mixed $pub_key_id
[, mixed $signature_alg
= OPENSSL_ALGO_SHA1
] ) openssl_verify() verifies that the
signature
is correct for the specified
data
using the public key associated with
pub_key_id
. This must be the public key
corresponding to the private key used for signing.
data
The string of data used to generate the signature previously
signature
A raw binary string, generated by openssl_sign() or similar means
pub_key_id
resource - a key, returned by openssl_get_publickey()
string - a PEM formatted key, example, "-----BEGIN PUBLIC KEY----- MIIBCgK..."
signature_alg
int - one of these Signature Algorithms.
string - a valid string returned by openssl_get_md_methods() example, "sha1WithRSAEncryption" or "sha512".
Returns 1 if the signature is correct, 0 if it is incorrect, and -1 on error.
版本 | 说明 |
---|---|
5.2.0 |
The signature_alg parameter was added.
|
Example #1 openssl_verify() example
<?php
// $data and $signature are assumed to contain the data and the signature
// fetch public key from certificate and ready it
$pubkeyid = openssl_pkey_get_public ( "file://src/openssl-0.9.6/demos/sign/cert.pem" );
// state whether signature is okay or not
$ok = openssl_verify ( $data , $signature , $pubkeyid );
if ( $ok == 1 ) {
echo "good" ;
} elseif ( $ok == 0 ) {
echo "bad" ;
} else {
echo "ugly, error checking signature" ;
}
// free the key from memory
openssl_free_key ( $pubkeyid );
?>
Example #2 openssl_verify() example
<?php
//data you want to sign
$data = 'my data' ;
//create new private and public key
$private_key_res = openssl_pkey_new (array(
"private_key_bits" => 2048 ,
"private_key_type" => OPENSSL_KEYTYPE_RSA ,
));
$details = openssl_pkey_get_details ( $private_key_res );
$public_key_res = openssl_pkey_get_public ( $details [ 'key' ]);
//create signature
openssl_sign ( $data , $signature , $private_key_res , "sha1WithRSAEncryption" );
//verify signature
$ok = openssl_verify ( $data , $signature , $public_key_res , OPENSSL_ALGO_SHA1 );
if ( $ok == 1 ) {
echo "valid" ;
} elseif ( $ok == 0 ) {
echo "invalid" ;
} else {
echo "error: " . openssl_error_string ();
}
?>
[#1] attila dot m dot magyar at gmail dot com [2014-08-26 21:37:52]
mikey at badpenguins dot com -- validating an X509 certificate chain in php seems to be possible with openssl_x509_checkpurpose()
[#2] jeremie dot gomez at gmail dot com [2011-08-31 11:08:53]
You can actually use the public key as third parameter and not the certificate.
If you can't make it work, make sure that :
1) Your public key is well formatted. It seems that it must have the ----BEGIN PUBLIC KEY---- and ----END PUBLIC KEY----
2) Your signature is in binary format. You can use the php base64_decode for this.
[#3] mikey at badpenguins dot com [2010-06-06 21:04:45]
I spent days scouring the php openssl documentation trying to figure out how to do what sounds like a simple task - given two PEM encoded certificates, is one the signer of the other? Nowhere in the openssl_verify() documentation or comments is it explained where to obtain the signature of an existing certificate. The openssl_x509_parse() function looked promising, but it is an unstable API that may change.
I had to write my own code to determine if one cert signed another, it is located here: http://badpenguins.com/source/misc/isCertSigner.php?viewSource
In a nutshell here is what I learned...
The signature data in a signed X.509 certificate contains DER formatted data about the signature that is encrypted with the signers public key. The data contains a hash of the original subject certificate and information about what encryption algorithm was used to create the signature.
So you need to get this signature data and a copy of the original certificate with the issuer and signature sequences removed. Hash a copy of the original certificate (sans issuer/signature sequences) with the same algorithm the issuer used and if the hashes match, you have the issuer cert that signed the certificate.
[#4] Stiv [2006-03-02 06:34:57]
I've finally found a way to verify signature. Sample in the documentation doesn't work. Code bellow DOES work :)
<?php
// $data is assumed to contain the data to be signed
// fetch certificate from file and ready it
$fp = fopen("path/file.pem", "r");
$cert = fread($fp, 8192);
fclose($fp);
// state whether signature is okay or not
// use the certificate, not the public key
$ok = openssl_verify($data, $signature, $cert);
if ($ok == 1) {
echo "good";
} elseif ($ok == 0) {
echo "bad";
} else {
echo "ugly, error checking signature";
}
?>
[#5] steve dot venable at lmco dot com [2002-05-30 12:36:09]
A note about the openssl_verify() (and some of the other functions). The public key comes from a certificate in any of the support formats (as the example shows, use openssl_get_publickey() to get the resource id). But after some trial and error I found the signature string MUST BE BINARY. While no error occurs, passing a base64-formatted signature string (PEM format?), you simply get a mismatch. When I did the base64 decode myself, the verify returned a match (return value 1). You can simply drop the begin/end lines and take the output of the 'base64_decode()' function.
[#6] meint dot post at bigfoot dot com [2001-06-09 11:56:41]
Anbybody trying to get a Win32 CryptoAPI based digital signature component to work with the openssl_verify() function should be aware that the CryptoAPI PKCS1 (RSA) method uses bytes in reverse order while the openssl_verify() method expects a correctly formatted PKCS1 digital signature (as should be). I learned this the hard way and it took me some time to dig this out. A simple solution in VBScript to reverse the byte order:
N = Len(Blob.Hex)
' reverse bytes in the signature using Hex format
For i = 1 To N - 1 Step 2
s = Mid(Blob, i, 2) & s
Next
s contains the digital signature in reverse order. Blob is an arbitrary binary container.
Send the signature off in Hex format and use a hex2bin method in PHP to convert to the correct format for openssl_verify(), i.e.
function hex2bin($data) {
$len = strlen($data);
return pack("H" . $len, $data);
}
That's it, hope it helps out. BTW I used ASPEncrypt to toy around with on Win32 platform. Works only with Internet Explorer but you could also use a Java applet and have none of the abovementioned problems :-)