(MFC) ClickBank Decrypt Instant Notification

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

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>
#include <CkBinData.h>
#include <CkCrypt2.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    // secret key from your ClickBank account
    const char *secretKey = "MY_SECRET_KEY";

    const char *jsonStr = "{\"notification\":\"BASE64_NOTIFICATION\",\"iv\":\"BASE64_IV\"}";

    CkJsonObject json;
    bool success = json.Load(jsonStr);

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

    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.

    CkCrypt2 crypt;
    // 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");
    const char *hexSha1 = crypt.hashStringENC(secretKey);
    strOut.append(hexSha1);
    strOut.append("\r\n");

    // Treat the hex string as binary data for the AES key..
    CkBinData bdKey;
    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);
    strOut.append("Decrypted: ");
    strOut.append(bdNotif.getString("utf-8"));
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }