(PHP Extension) RSA SHA256 Signature using Private Key from Java Keystore

Signs plaintext using RSA SHA256 using a key from a Java keystore.

Duplicatest this code:

KeyStore keystore; // key repository for keys containing signature certificate
String alias; // alias for the certificate in the key repository
String password; // password for the certificate's private key
String plaintext; // text being signed


Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign((PrivateKey) keystore.getKey(alias, password.toCharArray()));
signature.update(plaintext.getBytes("UTF-8"));
byte[] rsa_text= signature.sign();

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

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

<?php

include("chilkat.php");

$success = false;

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

$jks = new CkJavaKeyStore();

$jksPassword = 'secret';

// Load the Java keystore from a file.  The JKS file password is used
// to verify the keyed digest that is found at the very end of the keystore.
// It verifies that the keystore has not been modified.
$success = $jks->LoadFile($jksPassword,'qa_data/jks/sample_secret.jks');
if ($success == false) {
    print $jks->lastErrorText() . "\n";
    exit;
}

// Get the private key from the JKS.
// The private key password may be different than the file password.
$privKeyPassword = 'secret';
$caseSensitive = false;
// privKey is a CkPrivateKey
$privKey = $jks->FindPrivateKey($privKeyPassword,'some.alias',$caseSensitive);
if ($jks->get_LastMethodSuccess() == false) {
    print $jks->lastErrorText() . "\n";
    exit;
}

// Establish the RSA object and tell it to use the private key..
$rsa = new CkRsa();

$success = $rsa->UsePrivateKey($privKey);

if ($success == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

// Indicate we'll be signing the utf-8 byte representation of the string..
$rsa->put_Charset('utf-8');

// Sign some plaintext using RSA-SHA256
$binarySignature = new CkByteData();
$plaintext = 'this is the text to be signed';
$success = $rsa->SignString($plaintext,'SHA256',$binarySignature);
if ($rsa->get_LastMethodSuccess() == false) {
    print $rsa->lastErrorText() . "\n";
    exit;
}

// Alternatively, if the signature is desired in some encoded string form,
// such as base64, base64-url, hex, etc.
$rsa->put_EncodingMode('base64-url');
$signatureStr = $rsa->signStringENC($plaintext,'SHA256');
print 'base64-url RSA signature: ' . $signatureStr . "\n";

?>