RSA Signature/Verify with .key and .cer

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

 Chilkat Perl Module Downloads for Windows, Linux, and MAC OS X

use chilkat();

$privKey = new chilkat::CkPrivateKey();

#  Load the private key from an RSA .key file:
$success = $privKey->LoadPemFile("privateKey.key");
if ($success != 1) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

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

$rsa = new chilkat::CkRsa();

#  Any string argument automatically begins the 30-day trial.
$success = $rsa->UnlockComponent("30-day trial");
if ($success != 1) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

#  Import the private key into the RSA component:
$success = $rsa->ImportPrivateKey($privKeyXml);
if ($success != 1) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

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

#  If some other non-Chilkat application or web service is going to be verifying
#  the signature, it is important to match the byte-ordering.
#  The LittleEndian property may be set to 1
#  for little-endian byte ordering,
#  or 0  for big-endian byte ordering.
#  Microsoft apps typically use little-endian, while
#  OpenSSL and other services (such as Amazon CloudFront)
#  use big-endian.
$rsa->put_LittleEndian(0);

$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 . "\r\n";

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

$success = $cert->LoadFromFile("myCert.cer");
if ($success != 1) {
    print $cert->lastErrorText() . "\n";
    exit;
}

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

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

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

print "Success." . "\n";