FriendlyCaptcha (FRC) Solver

A standalone Rust-based solver for FriendlyCaptcha puzzles that exposes a standard HTTP API. It performs proof-of-work calculations using SIMD (blake2b_simd), fast-fails difficult puzzles, and spoofs execution telemetry to simulate normal browser solving speeds.

Note: This is currently a proof of concept. The solver may struggle with multiple concurrent threads/tasks at this stage.

Features

• High-Speed Execution: Uses SIMD and rayon for massive multithreading speedups.
• WASM Time Simulation: Calculates expected execution time of the in-browser WASM solver (~18 MH/s) and holds the solution until that time passes to spoof telemetry accurately.
• Difficulty Threshold Fast-Fail: Evaluates puzzle difficulty and immediately rejects it if the threshold is abnormally hard (threshold < 1000).
• Asynchronous Task Queue: Tasks are processed entirely in the background.

Requirements

• Rust toolchain (cargo)

Building & Running

Run the program via Cargo:

cd frc_solver
cargo build --release
cargo run --release

The server binds to 127.0.0.1:8989 by default.

API Documentation

Create a Task (/createTask)

Submits a new puzzle to be solved. If the puzzle is too difficult, it will return an immediate error, otherwise it responds with a task ID.

Endpoint: POST http://127.0.0.1:8989/createTask

Request Body (JSON):

{
  "puzzle": "SIGNATURE.BASE64_PAYLOAD",
  "activate_payload": { ... }, // Optional: If you want the solver to fetch the puzzle itself
  "proxy": "http://user:pass@ip:port" // Optional: Used to route the activate_payload request
}

Response (JSON):

{
  "errorId": 0,
  "taskId": "hex_string_task_id"
}

(If puzzle rejected due to length/difficulty: {"errorId": 1, "status": "too_long"})

Get Task Result (/getTaskResult)

Polls the solver for the result of a specific task. To maintain telemetry consistency, the server will intentionally hold the solution in the Processing state until the simulated WASM duration holds pass.

Endpoint: POST http://127.0.0.1:8989/getTaskResult

Request Body (JSON):

{
  "task_id": "hex_string_task_id"
}

Response (JSON - Expected):

{
  "errorId": 0,
  "status": "ready",
  "solution": {
    "frc_solution": "signature.b64_puzzle.b64_sol.b64_diag"
  }
}

Responses for pending / errored tasks:

• Processing: {"errorId": 0, "status": "processing"}
• Errored: {"errorId": 1, "status": "error", "errorDescription": "Error message"}