PHP ActiveX

Verify the RSA Signature of a SHA256 Hash

See more RSA Examples

Demonstrates how to verify an RSA signature of a SHA256 hash. PHP ActiveX

<?php

$success = 0;

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

// Let's say you have a file containing the 32-bytes of a SHA256 hash,
// and a file that is an RSA signature of those 32 bytes.
// Here's how you verify using the RSA public key found in a PEM.

$pubKey = new COM("Chilkat.PublicKey");
$success = $pubKey->LoadFromFile('rsaPubKey.pem');
if ($success == 0) {
    print $pubKey->LastErrorText . "\n";
    exit;
}

$rsa = new COM("Chilkat.Rsa");

// Get the public key.
$success = $rsa->UsePublicKey($pubKey);
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

// Get the 32-byte SHA256 hash.
$bdHash = new COM("Chilkat.BinData");
$success = $bdHash->LoadFile('myHash.sha256');
if ($success == 0) {
    print 'Failed to load SHA256 hash.' . "\n";
    exit;
}

// Get the RSA signature to be validated.
$bdSig = new COM("Chilkat.BinData");
$success = $bdSig->LoadFile('mySig.sig');
if ($success == 0) {
    print 'Failed to load RSA signature.' . "\n";
    exit;
}

// Verify the signature against the SHA256 hash.
$enc = 'base64';
$rsa->EncodingMode = $enc;
$success = $rsa->VerifyHashENC($bdHash->getEncoded($enc),'sha256',$bdSig->getEncoded($enc));
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

print 'Signature validated.' . "\n";

?>