(Perl) ClickBank Decrypt Instant Notification

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

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

# Get the encrypted notification (binary) and IV from the JSON.
$bdNotif = chilkat::CkBinData->new();
$bdIv = chilkat::CkBinData->new();

$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 = chilkat::CkCrypt2->new();
# 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 . "\r\n";

# Treat the hex string as binary data for the AES key..
$bdKey = chilkat::CkBinData->new();
$bdKey->AppendString($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") . "\r\n";