💻 Better CLI interface

Cargo.toml

@@ -5,4 +5,5 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[dependencies]
+[dependencies]
+clap = { version = "4.0", features = ["derive"] }

README.md

@@ -1,6 +1,27 @@
-# Encryption
-I created an encryption algorithm that can encrypt an arbitrary amount of data with a 64 bit key. 
+# Feistel Cipher
 
-## How it works.
-It uses a feinstel cipher where a PRNG is used as the round function. However, the feinstel cipher can only encrypt 64 bit blocks of data. 
-I use the counter mode of operation to encrypt arbitrary amount of data while encrypting identical blocks differently.
+## Usage
+
+```cli
+Usage: feistel [COMMAND]
+
+Commands:
+  encrypt  Encrypt data using Feistel cipher
+  decrypt  Decrypt data using Feistel cipher
+  help     Print this message or the help of the given subcommand(s)
+
+Options:
+  -h, --help     Print help
+  -V, --version  Print version
+```
+
+## Example
+
+```cli
+cat sensitive.png | feistel encrypt --key 123 > encrypted.dat
+cat encrypted.dat | feistel decrypt --key 123 > sensitive_decrypted.png
+```
+
+## About
+
+This Feistel cipher uses a PRNG as the round function. However, the feistel cipher can only encrypt 64 bit blocks of data. I use the counter mode of operation to encrypt arbitrary amount of data while encrypting identical blocks differently.

src/bin/feistel.rs

@@ -0,0 +1,51 @@
+use crypto::countermode::encrypt_stream;
+use crypto::countermode::decrypt_stream;
+
+use clap::{Arg, Command};
+use std::io::{self, Read, Write};
+
+fn main() {
+    // Define the CLI structure
+    let matches = Command::new("feistel")
+        .version("1.0")
+        .author("Adam Zawierucha")
+        .about("Feistel Cipher CLI using stdin and stdout")
+        .subcommand(
+            Command::new("encrypt")
+                .about("Encrypt data using Feistel cipher")
+                .arg(Arg::new("key")
+                    .short('k')
+                    .long("key")
+                    .value_name("NUMBER")
+                    .help("Encryption key (optional, default is 12345)")
+                    .default_value("1234567890")
+                    .value_parser(clap::value_parser!(u64))  
+            )
+        )
+        .subcommand(
+            Command::new("decrypt")
+                .about("Decrypt data using Feistel cipher")
+                .arg(Arg::new("key")
+                    .short('k')
+                    .long("key")
+                    .value_name("NUMBER")
+                    .help("Decryption key (optional, default is 12345)")
+                    .default_value("1234567890")
+                    .value_parser(clap::value_parser!(u64))  
+           )
+        )
+        .get_matches();
+
+    let mut stdin: Box<dyn Read> = Box::new(io::stdin());
+    let mut stdout: Box<dyn Write> = Box::new(io::stdout());
+
+    if let Some(sub_matches) = matches.subcommand_matches("encrypt") {
+        let key = sub_matches.get_one::<u64>("key").unwrap(); // Since default_value guarantees presence
+
+        let _ = encrypt_stream(&mut stdin, &mut stdout, *key);
+    } else if let Some(sub_matches) = matches.subcommand_matches("decrypt") {
+        let key = sub_matches.get_one::<u64>("key").unwrap(); // Since default_value guarantees presence
+
+        let _ = decrypt_stream(&mut stdin, &mut stdout, *key);
+    }
+}