OpenSSL Functions
PHP Manual

openssl_verify

(PHP 4 >= 4.0.4, PHP 5)

openssl_verifyVerify signature

Description

int openssl_verify ( string $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.

Parameters

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".

Return Values

Returns 1 if the signature is correct, 0 if it is incorrect, and -1 on error.

Changelog

Version Description
5.2.0 The signature_alg parameter was added.

Examples

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_resOPENSSL_ALGO_SHA1);
if (
$ok == 1) {
    echo 
"valid";
} elseif (
$ok == 0) {
    echo 
"invalid";
} else {
    echo 
"error: ".openssl_error_string();
}
?>

See Also


OpenSSL Functions
PHP Manual