(PHP Extension) RSA Signature/Verify with .key and .cer

See more RSA Examples

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

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<?php

include("chilkat.php");

$success = false;

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

$privKey = new CkPrivateKey();

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

$rsa = new CkRsa();

// Import the private key into the RSA component:
$success = $rsa->UsePrivateKey($privKey);
if ($success == false) {
    print $rsa->lastErrorText() . "\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 sha256 hash algorithm.
// Other valid choices are "md2", "sha1", "sha384",
// "sha512", and "md5".
$hexSig = $rsa->signStringENC($strData,'sha256');

print $hexSig . "\n";

// Load a digital certificate from a .cer file:
$cert = new CkCert();

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

$pubKey = new CkPublicKey();
$cert->GetPublicKey($pubKey);

// Now verify using a new instance of the RSA object:
$rsa2 = new CkRsa();

// Import the public key into the RSA object:
$success = $rsa2->UsePublicKey($pubKey);
if ($success == false) {
    print $rsa2->lastErrorText() . "\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,'sha256',$hexSig);
if ($success == false) {
    print $rsa2->lastErrorText() . "\n";
    exit;
}

print 'Success.' . "\n";

?>