(Perl) 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.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$privKey = chilkat::CkPrivateKey->new();

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

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

$rsa = chilkat::CkRsa->new();

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

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

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

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

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

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

print "Success." . "\r\n";