(PHP Extension) ClickBank Decrypt Instant Notification

Demonstrates how to decrypt a ClickBank instant notification. See Instant Notification Service for more information and alternative code snippets.

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

<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

// secret key from your ClickBank account
$secretKey = 'MY_SECRET_KEY';

$jsonStr = '{\'notification\':\'BASE64_NOTIFICATION\',\'iv\':\'BASE64_IV\'}';

$json = new CkJsonObject();
$success = $json->Load($jsonStr);

// Get the encrypted notification (binary) and IV from the JSON.
$bdNotif = new CkBinData();
$bdIv = new CkBinData();

$success = $bdNotif->AppendEncoded($json->stringOf('notification'),'base64');
$success = $bdIv->AppendEncoded($json->stringOf('iv'),'base64');

// Get an SHA1 digest (as a hex string) of the secret key.
// A SHA1 digest is 20 bytes.  Therefore the hex string is 40 chars.
// Treat each us-ascii char as a binary byte of the secret key.
// 256-bit AES needs a 256-bit key, which is 32-bytes.  Therefore
// use the 1st 32 us-ascii chars of the hex SHA1 as the AES secret key.

$crypt = new CkCrypt2();
// Because we're using the hex string as the actual AES key, it matters whether the hex is uppercase or lowercase.
// We want lowercase.
$crypt->put_EncodingMode('hex_lower');
$crypt->put_HashAlgorithm('sha1');
$hexSha1 = $crypt->hashStringENC($secretKey);
print $hexSha1 . "\n";

// Treat the hex string as binary data for the AES key..
$bdKey = new CkBinData();
$bdKey->AppendString($hexSha1,'us-ascii');
$bdKey->RemoveChunk(32,8);

$crypt->put_KeyLength(256);
$crypt->put_CryptAlgorithm('aes');
$crypt->put_CipherMode('cbc');

// We can use any encoding because were just getting the binary bytes in an encoding, and then setting from the same encoding.
// We'll just use base64..
$crypt->SetEncodedIV($bdIv->getEncoded('base64'),'base64');
$crypt->SetEncodedKey($bdKey->getEncoded('base64'),'base64');

$crypt->DecryptBd($bdNotif);
print 'Decrypted: ' . $bdNotif->getString('utf-8') . "\n";

?>