(PHP Extension) 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.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// 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 != true) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

// Get the private key in XML format:
$privKeyXml = $privKey->getXml();

$rsa = new CkRsa();

// Import the private key into the RSA component:
$success = $rsa->ImportPrivateKey($privKeyXml);
if ($success != true) {
    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 sha-1 hash algorithm.
// Other valid choices are "md2", "sha256", "sha384",
// "sha512", and "md5".
$hexSig = $rsa->signStringENC($strData,'sha-1');

print $hexSig . "\n";

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

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

// pubKey is a CkPublicKey
$pubKey = $cert->ExportPublicKey();

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

// Import the public key into the RSA object:
$success = $rsa2->ImportPublicKey($pubKey->getXml());
if ($success != true) {
    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,'sha-1',$hexSig);
if ($success != true) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

print 'Success.' . "\n";

?>