Perl

Verify the RSA Signature of a SHA256 Hash

See more RSA Examples

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

use chilkat();

$success = 0;

# 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.

$pubKey = chilkat::CkPublicKey->new();
$success = $pubKey->LoadFromFile("rsaPubKey.pem");
if ($success == 0) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

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

# Get the public key.
$success = $rsa->UsePublicKey($pubKey);
if ($success == 0) {
    print $rsa->lastErrorText() . "\r\n";
    exit;
}

# Get the 32-byte SHA256 hash.
$bdHash = chilkat::CkBinData->new();
$success = $bdHash->LoadFile("myHash.sha256");
if ($success == 0) {
    print "Failed to load SHA256 hash." . "\r\n";
    exit;
}

# Get the RSA signature to be validated.
$bdSig = chilkat::CkBinData->new();
$success = $bdSig->LoadFile("mySig.sig");
if ($success == 0) {
    print "Failed to load RSA signature." . "\r\n";
    exit;
}

# Verify the signature against the SHA256 hash.
$enc = "base64";
$rsa->put_EncodingMode($enc);
$success = $rsa->VerifyHashENC($bdHash->getEncoded($enc),"sha256",$bdSig->getEncoded($enc));
if ($success == 0) {
    print $rsa->lastErrorText() . "\r\n";
    exit;
}

print "Signature validated." . "\r\n";