PHP ActiveX

Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed. PHP ActiveX

<?php

$success = 0;

$bd = new COM("Chilkat.BinData");

for ($i = 0; $i <= 100; $i++) {
    $bd->AppendEncoded('000102030405060708090A0B0C0D0E0F','hex');
}

$sha256_base64 = $bd->getHash('sha256','base64');
print 'sha256 hash in base64 format: ' . $sha256_base64 . "\n";

$base64_rsa_sig = 'AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w==';

// Get the public key to be used for signature verification.
$pubKey = new COM("Chilkat.PublicKey");
$success = $pubKey->LoadFromFile('rsaKeys/chilkat-rsa-2048.pem');
if ($success == 0) {
    print $pubKey->LastErrorText . "\n";
    exit;
}

$rsa = new COM("Chilkat.Rsa");
$success = $rsa->UsePublicKey($pubKey);
if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    exit;
}

// Verify the hash against the signature.
$rsa->EncodingMode = 'base64';
$success = $rsa->VerifyHashENC($sha256_base64,'sha256',$base64_rsa_sig);

if ($success == 0) {
    print $rsa->LastErrorText . "\n";
    print 'Signature invalid.' . "\n";
}
else {
    print 'Signature valid.' . "\n";
}


?>