8 bit key; PRNG; XOR encryption

src/crypt/keys.rs

@@ -0,0 +1,46 @@
+/*
+ddtu - digital data transferring utility
+Copyright (C) 2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+*/
+
+use crate::crypt::rand;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub struct Key8bit {
+    pub k: u8,
+}
+
+impl Key8bit {
+    pub fn new(key: u8) -> Key8bit {
+        return Key8bit{
+            k: key,
+        }
+    }
+
+    pub fn new_random() -> Key8bit {
+        return Key8bit{
+            k: rand::rand_u16(SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_secs() as u16) as u8,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::crypt::keys::Key8bit;
+
+    #[test]
+    fn test_key8bit_generation() {
+        assert_eq!(Key8bit::new(255).k, 255);
+        Key8bit::new_random();
+    }
+}

src/crypt/mod.rs

@@ -0,0 +1,3 @@
+pub mod keys;
+pub mod rand;
+pub mod xor;

src/crypt/rand.rs

@@ -14,9 +14,19 @@ GNU Affero General Public License for more details.
 */
 
 
-pub const CONNECTION_SHUTDOWN_PACKET_ID: u8 = 1;
-pub const TEXT_PACKET_ID: u8 = 2;
-pub const FILEINFO_PACKET_ID: u8 = 3;
-pub const FILEDATA_PACKET_ID: u8 = 4;
+pub fn rand_u16(seed: u16) -> u16 {
+    return ((seed & 47851) + (seed >> 8 | 7943)) as u16;   
+}
 
-pub const CHUNK_SIZE: usize = 262_144; // 256 KB
+#[cfg(test)]
+mod tests {
+    use crate::crypt::rand::rand_u16;
+
+    #[test]
+    fn test_rand_u16() {
+        assert_eq!(rand_u16(10), 7953);
+        assert_eq!(rand_u16(12345), 20320);
+        assert_eq!(rand_u16(60000), 51791);
+        assert_eq!(rand_u16(64550), 55329);
+    }
+}

src/crypt/xor.rs

@@ -0,0 +1,50 @@
+/*
+ddtu - digital data transferring utility
+Copyright (C) 2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+*/
+
+use crate::crypt::keys::Key8bit;
+
+pub fn encrypt(plain: &mut [u8], key: &Key8bit) {
+    for i in 0..plain.len() {
+        plain[i] = plain[i] ^ key.k;
+    }
+}
+
+pub fn decrypt(encrypted: &mut[u8], key: &Key8bit) {
+    for i in 0..encrypted.len() {
+        encrypted[i] = encrypted[i] ^ key.k;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::crypt::keys::Key8bit;
+    use crate::crypt::xor;
+
+    #[test]
+    fn test_xor() {
+        let plaintext = "plain text 123";
+        let mut plaintext_bytes: Vec<u8> = Vec::with_capacity(plaintext.bytes().len());
+        for b in plaintext.bytes() {
+            plaintext_bytes.push(b);
+        } 
+
+        let key = Key8bit::new(45);
+    
+        xor::encrypt(&mut plaintext_bytes, &key);    
+        xor::decrypt(&mut plaintext_bytes, &key);
+
+        assert_eq!(String::from_utf8_lossy(&plaintext_bytes), plaintext);
+    }
+}

src/main.rs

@@ -16,6 +16,7 @@ GNU Affero General Public License for more details.
 mod util;
 mod protocol;
 mod args;
+mod crypt;
 mod fsys;
 
 use args::parser::{Args, RunMode};

src/nodes/node.rs

@@ -0,0 +1,9 @@
+pub struct Node {
+
+}
+
+impl Node {
+    pub fn new() -> Node {
+        return Node{};
+    }
+}

src/protocol/mod.rs

@@ -1,3 +1,2 @@
 pub mod packets;
-pub mod constants;
 pub mod specs;

src/protocol/packets.rs

@@ -15,7 +15,6 @@ GNU Affero General Public License for more details.
 
 use crate::util::error::Error;
 use crate::util::buf_read::{read_u128_slice, read_utf8_string_slice};
-use crate::protocol::constants;
 use crate::protocol::specs::*;
 use crate::fsys::file::ChunkedFile;
 
@@ -46,7 +45,7 @@ impl Packet for TextPacket {
     fn as_bytes(&self) -> Vec<u8> {
         let mut packet_as_bytes: Vec<u8> = Vec::<u8>::new();
 
-        packet_as_bytes.extend_from_slice(&constants::TEXT_PACKET_ID.to_be_bytes());
+        packet_as_bytes.extend_from_slice(&TEXT_PACKET_ID.to_be_bytes());
 
         let text_length: u128 = self.text.len() as u128;
         packet_as_bytes.extend_from_slice(&text_length.to_be_bytes());
@@ -64,7 +63,7 @@ impl Packet for TextPacket {
 
         // retrieve and check for packet type byte
         match packet_bytes[0].to_be() {
-            constants::TEXT_PACKET_ID => {}
+            TEXT_PACKET_ID => {}
             _ => {
                 return Some(Error::new("packet type is not of a text packet"));
             }
@@ -207,7 +206,7 @@ impl Packet for FileInfoPacket {
 pub struct FileDataPacket {
     pub file_id: u128,
     pub chunk_no: u128,
-    pub chunk: [u8; constants::CHUNK_SIZE],
+    pub chunk: [u8; CHUNK_SIZE],
 }
 
 impl FileDataPacket {
@@ -215,7 +214,7 @@ impl FileDataPacket {
         return FileDataPacket {
             file_id: 0,
             chunk_no: 0,
-            chunk: [0; constants::CHUNK_SIZE],
+            chunk: [0; CHUNK_SIZE],
         }
     }
 }
@@ -272,7 +271,39 @@ impl Packet for ConnectionShutdownPacket {
     }
 
     fn as_bytes(&self) -> Vec<u8> {
-        return vec!(constants::CONNECTION_SHUTDOWN_PACKET_ID.to_be_bytes()[0]);
+        return vec!(CONNECTION_SHUTDOWN_PACKET_ID.to_be_bytes()[0]);
+    }
+
+    fn from_bytes(&mut self, _packet_bytes: Vec<u8>) -> Option<Error> {
+        return None;
+    }
+}
+
+pub struct HandshakePaket {
+    pub protocol_version: u8,
+    pub use_encryption: bool,
+    pub encryption_type: u8,
+    pub encryption_key: Vec<u8>,
+}
+
+impl HandshakePaket {
+    fn empty() -> HandshakePaket {
+        return HandshakePaket{
+            protocol_version: PROTOCOL_LATEST_VERSION,
+            use_encryption: false,
+            encryption_type: ECRYPTION_XOR,
+            encryption_key: vec!(0, 0, 0, 0, 0, 0, 0, 0),
+        };
+    }
+}
+
+impl Packet for HandshakePaket {
+    fn get_type(&self) -> PacketType {
+        return PacketType::Handshake;
+    }
+
+    fn as_bytes(&self) -> Vec<u8> {
+        return vec!(HANDSHAKE_PACKET_ID.to_be_bytes()[0]);
     }
 
     fn from_bytes(&mut self, _packet_bytes: Vec<u8>) -> Option<Error> {

src/protocol/specs.rs

@@ -20,10 +20,11 @@ GNU Affero General Public License for more details.
 
 First 16 bytes - the total packet length
 The next 1 byte - number that represents this packet's type (ID) where:
-1: CONNECTION SHUTDOWN PACKET
-2: TEXT PACKET
-3: FILEINFO PACKET
-4: FILEDATA PACKET
+1: HANDSHAKE PACKET
+2: CONNECTION SHUTDOWN PACKET
+3: TEXT PACKET
+4: FILEINFO PACKET
+5: FILEDATA PACKET
 
 Then the internal structure varies from one packet type to the other,
 but the content-types are encoded as follows:
@@ -34,19 +35,35 @@ String - u128 representing the string length and then UTF-8 encoded character by
 */
 
 use crate::util::error::Error;
-use crate::protocol::constants;
 use crate::protocol::packets::*;
 
 use std::net;
 use std::io::Write;
 use std::io::Read;
 
+// Protocol versioning
+pub const PROTOCOL_LATEST_VERSION: u8 = 1;
+
+// Packets' IDs
+pub const HANDSHAKE_PACKET_ID: u8 = 1;
+pub const CONNECTION_SHUTDOWN_PACKET_ID: u8 = 2;
+pub const TEXT_PACKET_ID: u8 = 3;
+pub const FILEINFO_PACKET_ID: u8 = 4;
+pub const FILEDATA_PACKET_ID: u8 = 5;
+
+// File chunk size
+pub const CHUNK_SIZE: usize = 262_144; // 256 KB
+
+// Encryption types
+pub const ECRYPTION_XOR: u8 = 1;
+
 #[derive(PartialEq, Eq)]
 pub enum PacketType {
     ConnectionShutdown,
     TextData,
     FileInfo,
     FileData,
+    Handshake,
 }
 
 pub trait Packet {
@@ -104,11 +121,11 @@ pub fn read_next_packet(conn: &mut net::TcpStream) -> Result<Box<dyn Packet>, Er
 
     let packet_type_byte: u8 = u8::from_be_bytes([packet_bytes[0]]);
     match packet_type_byte {
-        constants::CONNECTION_SHUTDOWN_PACKET_ID => {
+        CONNECTION_SHUTDOWN_PACKET_ID => {
             return Ok(Box::new(ConnectionShutdownPacket{}));
         }
 
-        constants::TEXT_PACKET_ID => {
+        TEXT_PACKET_ID => {
             let mut new_text_packet: TextPacket = TextPacket::empty();
             let result = new_text_packet.from_bytes(packet_bytes);
             match result {
@@ -122,7 +139,7 @@ pub fn read_next_packet(conn: &mut net::TcpStream) -> Result<Box<dyn Packet>, Er
             }
         }
 
-        constants::FILEINFO_PACKET_ID => {
+        FILEINFO_PACKET_ID => {
             let mut new_fileinfo_packet: FileInfoPacket = FileInfoPacket::empty();
             let result = new_fileinfo_packet.from_bytes(packet_bytes);
             match result {
@@ -136,7 +153,7 @@ pub fn read_next_packet(conn: &mut net::TcpStream) -> Result<Box<dyn Packet>, Er
             }
         }
 
-        constants::FILEDATA_PACKET_ID => {
+        FILEDATA_PACKET_ID => {
             let mut new_filedata_packet: FileDataPacket = FileDataPacket::empty();
             let result = new_filedata_packet.from_bytes(packet_bytes);
             match result {