Authorized Security Audit 7 Iterations Completed

Breaking & Hardening
Client-Side Cryptography

An authorized penetration testing study on KofiType (created by Amar) — systematically testing client-side integrity across 7 progressive iterations from raw JSON tampering to AES-256-GCM, zero-width steganography, Discord webhook interception, and runtime bootloader analysis.

Test In-Browser Forge Download Chrome Extension View GitHub Source

Target: kofitype.vercel.app

Researcher: Javed Hussain

Developer: Amar

License: MIT Open Source

kofitype-audit-suite ~ bash

LIVE LOG

$ audit --target kofitype.vercel.app --rounds 7

[09:12:01] Initializing Guardian security analyzer...

[09:12:02] Target active: kofitype.vercel.app (Amar)

[09:12:03] ✓ V1: Plain JSON state tampered

[09:12:04] ✓ V2: Base64 obfuscation reversed

[09:12:05] ✓ V3: XOR checksum calculated: (xp*lvl*t) ^ token

[09:12:06] ✓ V4: Zero-width steganography unpacked (\\u200B/\\u200C)

[09:12:07] ✓ V5: AES-256-GCM runtime key derived: 4004198119

[09:12:08] ✓ V6: Discord gate hooked — auto-reaction served in 2.5s

[09:12:09] ✓ V7: Bootloader neutralized at document_start

[09:12:10] Auditor report: Pure client-side validation is fundamentally unviable.

[09:12:11] ● Audit status: COMPLETE. Recommendations delivered to Amar.

The Research Background

A Friendly Duel in Client-Side Defense

KofiType is a cozy coffee-themed typing app with competitive WPM tracking and leveling. To keep the leaderboards honest, developer Amar created Guardian — a client-side anti-tamper system. He invited Javed to attempt to break it.

Amar's Defensive Objective

Ensure that players cannot open Notepad or Chrome DevTools to edit their saved WPM, level, or XP. Protect export files (.kofi) against tampering, inject cryptographic signatures, and introduce verification gates.

Hide variables via closure obfuscation
Use AES-256-GCM encryption with runtime keys
Encode encrypted data into invisible Unicode characters
Require a human Discord emoji reaction before stats import
Enforce SHA-256 bootloader self-integrity checks

Javed's Research Methodology

Demonstrate the fundamental cryptographic reality: Any secret or integrity check running purely inside an untrusted client (the user's browser) can be reverse-engineered, extracted, or bypassed.

Extract dynamic encryption keys from minified source
Reverse zero-width unicode into raw binary bitstreams
Build automated standalone payload generators (Forge)
Create Chrome MV3 Extension to hook window.fetch at document_start
Auto-respond to Discord approval checks with simulated reactions

Progressive Research Cycles

The 7-Round Defense Matrix

Click on any version below to see how each defense layer was conceived by Amar, audited by Javed, and ultimately evolved into the next generation.

V1 — Plain JSON State

Target: Plain text export and unencrypted localStorage

Round 1

Amar's Defense

The initial release of KofiType stored user stats (WPM, level, tests completed) directly as standard JSON objects in localStorage and export files.

Javed's Audit & Tool

Simply opening DevTools or editing the exported file in Notepad allowed setting WPM to 999. Built Forge V1 to generate instant custom profiles.

Architectural Takeaway

Client-side data with zero cryptographic envelope offers no barrier against even non-technical users.

Live Demonstration

Interactive Payload Forge

Test the actual AES-256-GCM encryption and zero-width steganography engine right in your browser. Configure stats below and download a verified .kofi file that can be loaded into KofiType!

KofiType V5/V6/V7 Cryptographic Payload Generator

Combines AES-256-GCM subtle crypto + XOR checksum + Zero-Width Unicode steganography.

SECURITY TOKEN:

Username

Best WPM

Accuracy (%)

Level

Tests Completed

Time Typed (sec)

Practice Mode

XOR Checksum (xp * lvl * tests ^ token): Calculating...

Derived AES Key Hex: Calculating...

Steganographic Bitstream: Invisible Unicode (\u200B / \u200C)

Open KofiType to Import

The Reverse Engineering Suite

Chrome Extension: KofiType Toolkit

When KofiType introduced the Discord webhook human verification gate, a simple HTML generator was no longer enough. Javed engineered a full Manifest V3 Chrome Extension to hook network calls and neutralize debugger traps in real time.

Manifest V3 Compliant · Zero Inline CSP Violations

Complete Network & State Control

The KofiType Toolkit runs in three distinct execution contexts to provide transparent interception:

document_start Hooking (injected.js):

Wraps window.fetch before KofiType scripts execute. Neutralizes setInterval(debugger) and restores nullified console methods.

Auto-Reaction Simulator (background.js):

When a file import triggers a Discord webhook POST, the extension intercepts it, creates a fake message ID, and serves a 👍 emoji response after 2.5s.

Standalone AES-GCM Forge Popup:

Runs the full encryption and steganography pipeline directly inside the extension popup window — works on any tab without external dependencies.

Download Extension (.zip, 323 KB) View Extension Source

Detected Token

4004198119

User: Javed

WPM: 225

Level: 65

Acc: 99%

Fetch Interception Hook

Intercept Discord webhooks

ENABLED

When enabled, all POST calls to Discord webhooks receive a simulated message ID. The background service automatically serves a 👍 reaction within 2.5s to approve file imports instantly.

Current Page State (localStorage)

user: "Javed"

bestWpm: 225

testsCompleted: 750

timeTyped: 45000s

guardianChecksum: Valid ✓

[FETCH] POST /api/verify -> fakeId_8921

[TIMER] Scheduled reaction in 2500ms

[REACTION] Served 👍 for msg_fakeId_8921

[DEBUG] Traps neutralized at document_start

Mathematical Security

The Token Derivation Algorithm

How KofiType calculates the SECURITY_TOKEN dynamically from its own minified JavaScript source code — and why browser architecture permits reverse engineering it.

KofiType Token Derivation Formula

const rawSource = __KOFITYPE_CORE__.toString().replace(/\s+/g, '');

// 1. Compute SHA-256 hash of minified code
const msgBuffer = new TextEncoder().encode(rawSource);
const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
const hashHex = Array.from(new Uint8Array(hashBuffer))
  .map(b => b.toString(16).padStart(2, '0'))
  .join('');

// 2. Take first 8 hex characters as 32-bit integer
const token = parseInt(hashHex.slice(0, 8), 16);
console.log("Live Token:", token);

Interactive Hash & Token Simulator

Type any sample code or text below to watch the SHA-256 and resulting integer token compute live:

SHA-256: Computing...

First 8 Hex: ...

Derived Token: ...

Research Collaboration

Researchers & Attribution

This project represents an ethical, fully authorized engineering exercise between a cybersecurity researcher and an application creator.

Authorized Testing & Ethical Disclosure Notice

This audit was conducted strictly with explicit permission from the target application's developer (Amar). No live user accounts, private databases, or confidential records were accessed or compromised. All exploit tools and bypass logic are documented solely for educational analysis and to demonstrate client-side security limits.

Breaking & Hardening Client-Side Cryptography