PHP Extension Requires Chilkat v11.0.0+

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. PHP Extension

<?php

include("chilkat.php");

$success = false;

//  This example assumes the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

$privKey = new CkPrivateKey();

//  Load the private key from an RSA .key file:
$success = $privKey->LoadPemFile('privateKey.key');
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

$rsa = new CkRsa();

//  Import the private key into the RSA component:
$success = $rsa->UsePrivateKey($privKey);
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

//  Create the signature as a hex string:
$rsa->put_EncodingMode('hex');

$strData = 'This is the string to be signed.';

//  Sign the string using the sha256 hash algorithm.
//  Other valid choices are "md2", "sha1", "sha384",
//  "sha512", and "md5".
$hexSig = $rsa->signStringENC($strData,'sha256');

print $hexSig . "\n";

//  Load a digital certificate from a .cer file:
$cert = new CkCert();

$success = $cert->LoadFromFile('myCert.cer');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

$pubKey = new CkPublicKey();
$cert->GetPublicKey($pubKey);

//  Now verify using a new instance of the RSA object:
$rsa2 = new CkRsa();

//  Import the public key into the RSA object:
$success = $rsa2->UsePublicKey($pubKey);
if ($success == false) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

//  The signature is a hex string, so make sure the EncodingMode is correct:
$rsa2->put_EncodingMode('hex');

//  Verify the signature:
$success = $rsa2->VerifyStringENC($strData,'sha256',$hexSig);
if ($success == false) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

print 'Success.' . "\n";

?>