(Perl) ECDSA Sign and Verify Data using Different Hash Algorithms

Demonstrates how to create ECDSA signatures on data using different hash algorithms.

Note: This example requires Chilkat v9.5.0.85 or greater because the SignBd and VerifyBd methods were added in v9.5.0.85.

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use chilkat();

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

# First load an ECDSA private key to be used for signing.
$privKey = chilkat::CkPrivateKey->new();
$success = $privKey->LoadEncryptedPemFile("qa_data/ecc/secp256r1-key-pkcs8-secret.pem","secret");
if ($success == 0) {
    print $privKey->lastErrorText() . "\r\n";
    exit;
}

# Load some data to be signed.
$bd = chilkat::CkBinData->new();
$success = $bd->LoadFile("qa_data/hamlet.xml");
if ($success == 0) {
    print "Failed to load file to be hashed." . "\r\n";
    exit;
}

$ecdsa = chilkat::CkEcc->new();
$prng = chilkat::CkPrng->new();

# Sign the sha256 hash of the data.  Return the ECDSA signature in the base64 encoding.
print "ECDSA signing the sha256 hash of the data..." . "\r\n";
$sig = $ecdsa->signBd($bd,"sha256","base64",$privKey,$prng);
print "sig = " . $sig . "\r\n";

# Verify the signature against the original data.
# (We must use the same hash algorithm that was used when signing.)

# Load the public key that corresponds to the private key used for signing.
$pubKey = chilkat::CkPublicKey->new();
$success = $pubKey->LoadFromFile("qa_data/ecc/secp256r1-pub.pem");
if ($success == 0) {
    print $pubKey->lastErrorText() . "\r\n";
    exit;
}

$ecc2 = chilkat::CkEcc->new();
$result = $ecc2->VerifyBd($bd,"sha256",$sig,"base64",$pubKey);
if ($result != 1) {
    print $ecc2->lastErrorText() . "\r\n";
    exit;
}

print "Verified!" . "\r\n";

# ----------------------------------------------------------------------------------------
# Let's do the same thing, but with sha384 hashing...

print "--------------------------------------------" . "\r\n";
print "ECDSA signing the sha384 hash of the data..." . "\r\n";

$sig = $ecdsa->signBd($bd,"sha384","base64",$privKey,$prng);
print "sig = " . $sig . "\r\n";

$result = $ecc2->VerifyBd($bd,"sha384",$sig,"base64",$pubKey);
if ($result != 1) {
    print $ecc2->lastErrorText() . "\r\n";
    exit;
}

print "Verified!" . "\r\n";