https://github.com/elkronos/decaptcha

Prove you're not human.
https://github.com/elkronos/decaptcha

bots captcha python

Last synced: about 1 year ago
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Prove you're not human.

• Host: GitHub
• URL: https://github.com/elkronos/decaptcha
• Owner: elkronos
• Created: 2025-04-06T20:50:06.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2025-04-07T02:53:31.000Z (about 1 year ago)
• Last Synced: 2025-04-07T03:31:20.746Z (about 1 year ago)
• Topics: bots, captcha, python
• Language: Python
• Homepage:
• Size: 5.86 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Decaptcha: Bot Access Challenge System

This repository implements an advanced challenge-response system designed to distinguish bots from human users by issuing puzzles that are trivial for automated algorithms yet tedious for humans. The system leverages high-resolution timing, dynamic difficulty adjustments, cryptographic handshakes, and multiple puzzle types to ensure robust access control.

---

## Features

- **High-Resolution Timing Enforcement:**  

  Utilizes both wall-clock timestamps and Python's `time.perf_counter()` to capture precise response times. Bots are expected to solve puzzles within a very narrow time window, while human responses typically fall outside this range.

- **Dynamic Difficulty Adjustment:**  

  Monitors failure counts and adjusts the complexity of the challenges accordingly. For example, after multiple failed attempts, the Proof-of-Work (PoW) difficulty is incremented and arithmetic challenge ranges are widened, making manual solving even more difficult.

- **Integrated Cryptographic Handshake:**  

  Incorporates HMAC-based signatures using a secret key known only to legitimate bots. This additional check ensures that even if a human manages to solve the puzzle, they cannot generate the correct signature without the secret.

- **Behavior Logging and Analysis:**  

  Detailed logs capture metrics such as response times (both wall-clock and high-resolution), client identity, and specific failure reasons. These logs can be analyzed over time to identify suspicious activity and refine challenge parameters.

- **Client Identity Binding:**  

  The challenges are tied to a unique `client_id` (such as an IP address or session ID) to prevent challenge reuse or bypass through multiple clients.

- **Multiple Challenge Types:**  

  Supports a mix of puzzles, including:

  - **Proof of Work (PoW):** A simple hash-based puzzle.

  - **Arithmetic Challenge:** A modular exponentiation problem.

  - **Pattern Challenge:** A Fibonacci sequence puzzle.

  - **Optional String Reversal Challenge:** Randomly included to further complicate manual solving.

---

## Requirements

- **Python 3.x**  

  All libraries used (e.g., `time`, `hmac`, `hashlib`, `random`, `json`, `logging`, `string`) are part of the Python Standard Library, so no additional installations are necessary.

---

## Installation & Setup

1. **Clone the Repository:**

   ```bash

   git clone https://github.com/elkronos/decaptcha.git

   cd decaptcha