Introduction
The Bacon Cipher is a simple steganographic technique invented by Sir Francis Bacon in the 16th century. It encodes messages by representing each letter with a binary sequence, usually consisting of two distinguishable symbols. In this tutorial, we will walk you through implementing the Bacon Cipher in Rust, covering both encoding and decoding functionalities.
Project Setup
Before we dive into the code, make sure you have Rust installed on your system. You can check this by running:
If Rust is not installed, follow the official installation guide.
Step 1: Creating the Rust Project
Create a new Rust project using Cargo:
cargo new bacon_cipher
cd bacon_cipher
Step 2: Implementing the Bacon Cipher in Rust
Open the src/main.rs file and follow the steps below.
Step 2.1: Define the Bacon Mapping
use std::collections::HashMap;
fn get_bacon_mapping() -> HashMap<char, &'static str> {
let mut mapping = HashMap::new();
let alphabet = [
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
];
let codes = [
"AAAAA", "AAAAB", "AAABA", "AAABB", "AABAA", "AABAB", "AABBA", "AABBB",
"ABAAA", "ABAAB", "ABABA", "ABABB", "ABBAA", "ABBAB", "ABBBA", "ABBBB",
"BAAAA", "BAAAB", "BAABA", "BAABB", "BABAA", "BABAB", "BABBA", "BABBB",
"BBAAA", "BBAAB",
];
for (i, &ch) in alphabet.iter().enumerate() {
mapping.insert(ch, codes[i]);
}
mapping
}
This function returns a HashMap containing the letter-to-code mappings according to the Bacon Cipher.
Step 2.2: Encoding a Message
fn encode_message(message: &str) -> String {
let mapping = get_bacon_mapping();
let mut encoded = String::new();
for ch in message.to_uppercase().chars() {
if let Some(&code) = mapping.get(&ch) {
encoded.push_str(code);
}
}
encoded
}
fn main() {
let message = "HELLO";
let encoded = encode_message(message);
println!("Encoded message: {}", encoded);
}
In this example, the message HELLO is encoded using the Bacon mapping, outputting a sequence of A's and B's.
Step 2.3: Decoding a Message
To decode a message, we need to reverse the mapping and convert sequences of A's and B's back to letters.
fn decode_message(encoded: &str) -> String {
let mapping = get_bacon_mapping();
let mut reversed_mapping = HashMap::new();
for (&key, &value) in &mapping {
reversed_mapping.insert(value, key);
}
let mut decoded = String::new();
let mut buffer = String::new();
for ch in encoded.chars() {
buffer.push(ch);
if buffer.len() == 5 {
if let Some(&decoded_char) = reversed_mapping.get(&buffer.as_str()) {
decoded.push(decoded_char);
}
buffer.clear();
}
}
decoded
}
fn main() {
let message = "HELLO";
let encoded = encode_message(message);
println!("Encoded message: {}", encoded);
let decoded = decode_message(&encoded);
println!("Decoded message: {}", decoded);
}
The decode_message function reads chunks of 5 characters and translates them back to their corresponding letters using the reversed mapping.
Step 3: Running the Program
To test the implementation, run:
You should see output similar to:
Encoded message: AABAAABABAABBABAAABBB
Decoded message: HELLO