Catch the flag competition over RISC Zero (Season 1)

This repo contains a catch-the-flag challenge in RISC Zero.

Contestants are asked to design inputs to the guest program running inside the RISC Zero VM. The goal is to let main.rs output "You have successfully solved this RISC Zero challenge."

Note that this means that a correct receipt (i.e., a zero-knowledge proof) is needed in order to have RISC Zero accept the submission.

If you solve this challenge, send your solution to Weikeng Chen at w.k@berkeley.edu .

Prize

I am prepared to give out some small cash prizes (around $20 each) to the earliest 20 qualified submissions.

We have already received 3 qualified submissions.

Code

use risc0_zkvm::{default_prover, ExecutorEnv};

const PROGRAM_CODE: &'static [u8] = include_bytes!("code");
const PROGRAM_ID: [u32; 8] = [
    4089023768u32,
    3145240833u32,
    1747178994u32,
    3214649236u32,
    3131642364u32,
    1474811960u32,
    1082230595u32,
    3832750910u32,
];

fn main() {
    /***************************************************************/

    /* Edit this area to provide your input to the guest program. */

    let mut input = Vec::<u8>::with_capacity(64);
    for i in 0..64 {
        input.push(i as u8);
    }

    /***************************************************************/

    let env = ExecutorEnv::builder()
        .write(&input)
        .unwrap()
        .build()
        .unwrap();

    let prover = default_prover();

    if prover.get_name() != "bonsai" {
        println!("You are recommended to use the Bonsai API for best experience if you have the Bonsai API key.");
    }

    let mut success_flag = true;

    let receipt = prover.prove_elf(env, PROGRAM_CODE);

    let expected = b"You have successfully solved this RISC Zero challenge.".to_vec();

    if receipt.is_err() {
        success_flag = false;
    } else {
        let receipt = receipt.unwrap();

        let verify_result = receipt.verify(PROGRAM_ID);
        if verify_result.is_err() {
            success_flag = false;
        }

        let data = receipt.journal.bytes;
        if data != expected {
            success_flag = false;
        }
    }

    if success_flag {
        println!("You have successfully solved this RISC Zero challenge.");
    } else {
        println!("Try again!");
    }
}

Hints

Although I am not going to give out problem-specific hints, people who want to understand RISC Zero, particularly low-level details, may benefit from this blog article:

Tech Deep Dive: Verifying FHE in RISC Zero, Part I

https://l2ivresearch.substack.com/p/tech-deep-dive-verifying-fhe-in-risc

weikengchen/zkctf-r0-season1

Catch the flag competition over RISC Zero (Season 1)

Prize

Code

Hints