(Perl) Convert RSA Private Key to Public Key

Demonstrates how to get a public RSA key from a private RSA key.

Note: This example requires Chilkat v11.0.0 or greater.

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

use chilkat();

$success = 0;

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

# Step 1: Load the private key from a source.
# (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
# see the online reference documentation for more options.)
$success = $privKey->LoadPemFile("qa_data/pem/VP_Private.pem");
if ($success == 0) {
    print $privKey->lastErrorText() . "\r\n";
    exit;
}

# Step 2: Get the public key object from the private key object.
$pubKey = chilkat::CkPublicKey->new();
$privKey->ToPublicKey($pubKey);

# Step 3: Save the public key in a desired format. 
# (Chilkat can load or save public and private keys in many different formats.  See
# the online reference documentation for more options.)

# Saves to a PKCS8 PEM file.
$bPreferPkcs1 = 0;
$success = $pubKey->SavePemFile($bPreferPkcs1,"qa_data/pem/VP_Public.pem");
if ($pubKey->get_LastMethodSuccess() == 0) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

print "Extracted and saved public key from private key." . "\r\n";