(PHP Extension) RSA Sign an Encoded Hash

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Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex).

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux, Solaris

<?php

include("chilkat.php");
// Use "chilkat_9_5_0.php" for versions of Chilkat < 10.0.0

// Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
// this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

// Chilkat automatically detects and determines the way in which the HSM is used,
// which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

$cert = new CkCert();

// Set the token/smartcard PIN prior to loading.
$cert->put_SmartCardPin('123456');

// Specify the certificate by its common name.
$success = $cert->LoadFromSmartcard('cn=chilkat-rsa-2048');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

print 'Signing with the private key for this cert: ' . $cert->subjectCN() . "\n";

// Create data to be hashed and signed.
$bd = new CkBinData();

for ($i = 0; $i <= 100; $i++) {
    $bd->AppendEncoded('000102030405060708090A0B0C0D0E0F','hex');
}

$rsa = new CkRsa();

// Use the certificate's private key for signing.
$success = $rsa->SetX509Cert($cert,true);
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

// We'll first compute the hash and then pass the encoded hash to be signed.
$sha256_base64 = $bd->getHash('sha256','base64');
print 'sha256 hash in base64 format: ' . $sha256_base64 . "\n";

// Pass in the base64 hash and return a base64 signature.
$rsa->put_EncodingMode('base64');
$rsaSig_base64 = $rsa->signHashENC($sha256_base64,'sha256');
if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

print 'RSA signature as base64: ' . $rsaSig_base64 . "\n";

?>