Perl Requires Chilkat v11.0.0+

Verify the RSA Signature of a SHA256 Hash

See more RSA Examples

Demonstrates how to verify an RSA signature of a SHA256 hash. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

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

# Let's say you have a file containing the 32-bytes of a SHA256 hash,
# and a file that is an RSA signature of those 32 bytes.
# Here's how you verify using the RSA public key found in a PEM.

my $pubKey = Chilkat2::PublicKey->new;
my $success = $pubKey->LoadFromFile('rsaPubKey.pem');
if (!$success) {
    print $pubKey->LastErrorText, "\n";
    exit;
}

my $rsa = Chilkat2::Rsa->new;

# Get the public key.
$success = $rsa->UsePublicKey($pubKey);
if (!$success) {
    print $rsa->LastErrorText, "\n";
    exit;
}

# Get the 32-byte SHA256 hash.
my $bdHash = Chilkat2::BinData->new;
$success = $bdHash->LoadFile('myHash.sha256');
if (!$success) {
    print "Failed to load SHA256 hash.\n";
    exit;
}

# Get the RSA signature to be validated.
my $bdSig = Chilkat2::BinData->new;
$success = $bdSig->LoadFile('mySig.sig');
if (!$success) {
    print "Failed to load RSA signature.\n";
    exit;
}

# Verify the signature against the SHA256 hash.
my $enc = 'base64';
$rsa->EncodingMode($enc);
$success = $rsa->VerifyHashENC($bdHash->GetEncoded($enc), 'sha256', $bdSig->GetEncoded($enc));
if (!$success) {
    print $rsa->LastErrorText, "\n";
    exit;
}

print "Signature validated.\n";