cryptopals/src/set1.rs

#![allow(dead_code)]
use crate::bytes::Bytes;
use crate::bytes_base64::BytesBase64;
use crate::{ecb, utils};
use std::io::Write;
use std::str;

pub fn challenge1() {
    let input = Bytes::from_hex("49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d");
    let expected = String::from("SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t");
    let result = BytesBase64::from_bytes(input);
    if result.to_string() == expected {
        println!("[okay] Challenge 1: {}", result);
    } else {
        println!("[fail] Challenge 1")
    }
}

pub fn challenge2() {
    let input_1 = Bytes::from_hex("1c0111001f010100061a024b53535009181c");
    let input_2 = Bytes::from_hex("686974207468652062756c6c277320657965");
    let result = Bytes::xor(&input_1, &input_2);
    let expected = Bytes::from_hex("746865206b696420646f6e277420706c6179");
    if result == expected {
        println!("[okay] Challenge 2: {}", result.to_hex());
    } else {
        println!("[fail] Challenge 2")
    }
}

pub fn challenge3() {
    let a = Bytes::from_hex("1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736");
    let mut h: Vec<Bytes> = (0..=255).map(|i| Bytes::xor_byte(&a, i)).collect();
    h.sort_by(|a, b| a.ascii_score().partial_cmp(&b.ascii_score()).unwrap());
    // let h: Vec<Bytes> = h.into_iter().filter(|b| b.is_ascii()).collect();
    let r = h.last().unwrap().to_utf8();
    println!("[okay] Challenge 3: {}", r);
}

pub fn challenge4() {
    let bytes_vector = utils::read_hex_lines("data/4.txt");
    let mut xored_bytes_vector: Vec<Bytes> = vec![];
    for i in 32..=127 {
        for bytes in bytes_vector.iter() {
            xored_bytes_vector.push(Bytes::xor_byte(bytes, i));
        }
    }
    xored_bytes_vector.sort_by(|a, b| a.ascii_score().partial_cmp(&b.ascii_score()).unwrap());
    let result = xored_bytes_vector.last().unwrap().to_utf8();
    println!("[okay] Challenge 4: {}", result.trim());
}

pub fn challenge5() {
    let msg = Bytes::from_utf8(
        "Burning 'em, if you ain't quick and nimble\nI go crazy when I hear a cymbal",
    );
    let key = Bytes::from_utf8("ICE");
    let enc = Bytes::xor_cycle(&msg, &key);
    let exp = Bytes::from_hex("0b3637272a2b2e63622c2e69692a23693a2a3c6324202d623d63343c2a26226324272765272a282b2f20430a652e2c652a3124333a653e2b2027630c692b20283165286326302e27282f");
    if enc == exp {
        println!("[okay] Challenge 5: {}", enc.to_hex());
    } else {
        println!("[fail] Challenge 5")
    }
}

pub fn challenge6() {
    fn _write(path: &str, bytes_base64: &BytesBase64) {
        let width = 60;
        let bytes = bytes_base64.to_string();
        let mut output_vec = vec![];

        for e in Iterator::zip(bytes.as_bytes().iter(), 0..bytes.len()) {
            if e.1 % width == 0 && e.1 > 0 {
                output_vec.push('\n' as u8)
            }
            output_vec.push(*e.0);
        }
        output_vec.push('\n' as u8);
        let mut f = std::fs::File::create(path).unwrap();
        f.write(&output_vec).unwrap();
    }

    fn _test_roundtrip() {
        // Test that conversion from to bytes and back works
        let bytes = utils::read_base64("data/6.txt");
        let bytes_base64 = BytesBase64::from_bytes(bytes);
        _write("data/6.txt", &bytes_base64);
    }

    fn rate(Bytes(v): &Bytes, size: usize) -> f32 {
        let (mut rating, mut iterations) = (0, 0);
        for c in v.chunks(size * 2) {
            if c.len() < size * 2 {
                break;
            }
            let (a, b) = c.split_at(size);
            rating += Bytes::hemming(&Bytes(a.to_vec()), &Bytes(b.to_vec()));
            iterations += 1;
        }
        (rating as f32 / iterations as f32) / size as f32
    }

    fn guess_key_size(bytes: &Bytes) -> usize {
        let (mut lowest_rating, mut lowest_size) = (f32::MAX, 0);
        for key_size in 2..40 {
            let rating = rate(&bytes, key_size);
            if rating < lowest_rating {
                lowest_rating = rating;
                lowest_size = key_size;
            }
        }
        lowest_size
    }

    fn transpose(Bytes(v): &Bytes, size: usize) -> Vec<Bytes> {
        let mut result = vec![];
        for i in 0..size {
            let mut column = vec![];
            for j in (i..v.len()).step_by(size) {
                column.push(v[j]);
            }
            result.push(Bytes(column));
        }
        result
    }

    _test_roundtrip();
    let bytes = utils::read_base64("data/6.txt");
    let key_size = guess_key_size(&bytes);
    let bytes_tranposed = transpose(&bytes, key_size);
    let key = Bytes(
        bytes_tranposed
            .iter()
            .map(|b| Bytes::guess_key(&b))
            .collect(),
    );
    let msg = Bytes::xor_cycle(&bytes, &key).to_utf8();

    let partial_msg = msg[..20].to_string();
    println!("[okay] Challenge 6: {}...", partial_msg);
}

pub fn challenge7() {
    let text = Bytes::from_utf8("We meet at burger king!");
    let key = Bytes::from_utf8("YELLOW SUBMARINE");
    let ciphertext = ecb::encrypt(&key, &text);
    let roundtrip = ecb::decrypt(&key, &ciphertext);
    if text != roundtrip {
        panic!("ECB roundtrip not working.");
    }
    let ciphertext = utils::read_base64("data/7.txt");
    let data = ecb::decrypt(&key, &ciphertext);
    let partial_msg = data.to_utf8()[..20].to_string();
    println!("[okay] Challenge 7: {}...", partial_msg);
}

pub fn challenge8() {
    fn rate(Bytes(v): &Bytes, size: usize) -> u32 {
        let mut rating = 0;
        let chunks: Vec<&[u8]> = v.chunks(size).collect();
        for i in 0..chunks.len() {
            for j in (i + 1)..chunks.len() {
                rating += Bytes::hemming(&Bytes(chunks[i].to_vec()), &Bytes(chunks[j].to_vec()));
            }
        }
        rating
    }

    let expected_index: usize = 132;
    let bytes_vector = utils::read_hex_lines("data/8.txt");
    let ratings: Vec<u32> = bytes_vector.iter().map(|b| rate(&b, 16)).collect();
    let min_rating = ratings.iter().min().unwrap();
    let index = ratings.iter().position(|e| e == min_rating).unwrap();
    let average = ratings.iter().sum::<u32>() as f32 / ratings.len() as f32;
    let partial_cipher = bytes_vector[index].to_hex()[..10].to_string();
    if index != expected_index {
        panic!("Regression in challenge 8.");
    }
    println!(
        "[okay] Challenge 8: Cipher {} [{}...] with rating {} (average = {}) is the solution.",
        index, partial_cipher, min_rating, average
    );

    // More elegant solution.
    let bytes_vector = utils::read_hex_lines("data/8.txt");
    let ix: Vec<usize> = bytes_vector
        .iter()
        .enumerate()
        .filter(|&(_, bytes)| bytes.has_duplicated_cycle(16))
        .map(|(i, _)| i)
        .collect();
    assert_eq!(ix[0], expected_index);
}