commit 38b72793ade642f0118b6d0e763aafb5a88073c9 Author: Trance-0 Date: Mon Feb 16 12:26:36 2026 -0600 init diff --git a/.env b/.env new file mode 100644 index 0000000..9b8a2ff --- /dev/null +++ b/.env @@ -0,0 +1,6 @@ +NET_SUBNET=172.30.0.0/24 +SERVER_IP=172.30.0.10 +CLIENT_IP=172.30.0.11 +SERVER_PORT=3030 +INITIAL_VECTOR=EA514659DC556DEECFFA5FD061363642 +SECRET_KEY=0214BA9480AE8D21842B80FF5287418FD0465113070FDFF8263F0F1FCD6CF030 \ No newline at end of file diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..ddd9f5a --- /dev/null +++ b/.gitignore @@ -0,0 +1,9 @@ +# latex garbages +*.aux +*.fdb_latexmk +*.fls +*.log +*.synctex.gz + +# vscode garbage +.vscode \ No newline at end of file diff --git a/CSE433S_HW2_net_block_cipher.pdf b/CSE433S_HW2_net_block_cipher.pdf new file mode 100644 index 0000000..4208d1d Binary files /dev/null and b/CSE433S_HW2_net_block_cipher.pdf differ diff --git a/client-log.sh b/client-log.sh new file mode 100644 index 0000000..d3c2268 --- /dev/null +++ b/client-log.sh @@ -0,0 +1 @@ +docker logs hw1-client \ No newline at end of file diff --git a/client.cpp b/client.cpp new file mode 100644 index 0000000..4be6aec --- /dev/null +++ b/client.cpp @@ -0,0 +1,192 @@ +#include +#include +#include +#include + +// open ssl +#include +#include +#include + +#include // error handling +#include // for close() + +// load environment variables from .env file +#include +#include + +void load_env(const std::string& path) { + std::ifstream f(path); + std::string line; + while (std::getline(f, line)) { + if (line.empty() || line[0] == '#') continue; + auto pos = line.find('='); + if (pos == std::string::npos) continue; + + std::string key = line.substr(0, pos); + std::string val = line.substr(pos + 1); + + #ifdef _WIN32 + _putenv_s(key.c_str(), val.c_str()); + #else + setenv(key.c_str(), val.c_str(), 1); + #endif + } +} + +// hex to byte helper function +int hex_to_bytes_upper(const char* hex, unsigned char* out, size_t out_size) +{ + size_t i = 0; + while (hex[0] && hex[1]) { + if (i >= out_size) return -1; + unsigned char h = hex[0]; + unsigned char l = hex[1]; + int hi = (h <= '9') ? (h - '0') : (h - 'A' + 10); + int lo = (l <= '9') ? (l - '0') : (l - 'A' + 10); + // minimal sanity check + if (hi < 0 || hi > 15 || lo < 0 || lo > 15) + return -1; + out[i++] = (unsigned char)((hi << 4) | lo); + hex += 2; + } + return (int)i; +} + +// block cipher encryption function +int block_encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key, unsigned char *iv, unsigned char *ciphertext) { + /* Declare cipher context */ + EVP_CIPHER_CTX *ctx; + + int len, ciphertext_len; + + /* Create and initialise the context */ + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) { + ERR_print_errors_fp(stderr); + } + + /* Initialise the encryption operation. */ + // choice for aes_256 ref: https://stackoverflow.com/questions/1220751/how-to-choose-an-aes-encryption-mode-cbc-ecb-ctr-ocb-cfb + if (EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv) != 1){ + ERR_print_errors_fp(stderr); + } + + /* Provide the message to be encrypted, and obtain the encrypted output. EVP_EncryptUpdate can be called multiple times if necessary */ + if (EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len) != 1) { + ERR_print_errors_fp(stderr); + } + + /* Finalize the encryption. Further cipher text bytes may be written at this stage. */ + if (EVP_EncryptFinal_ex(ctx, ciphertext + len, &ciphertext_len) != 1) { + ERR_print_errors_fp(stderr); + } + + /* Clean up */ + EVP_CIPHER_CTX_free(ctx); + + return ciphertext_len; +} + +int main(void){ + load_env(".env"); + // Declare variables + const char *server_ip = std::getenv("SERVER_IP"); + const int server_port = std::atoi(std::getenv("SERVER_PORT")); + printf("Connecting to server %s:%d\n", server_ip, server_port); + + char client_message[1024]; + char server_message[1024]; + const char * custom_message="Zheyuan Wu: "; + + // encryption parameters + const char *inital_vector = std::getenv("INITIAL_VECTOR"); + const char *secret_key = std::getenv("SECRET_KEY"); + unsigned char key_bytes[32], iv_bytes[16]; + + int key_len = hex_to_bytes_upper(secret_key, key_bytes, sizeof(key_bytes)); + int iv_len = hex_to_bytes_upper(inital_vector, iv_bytes, sizeof(iv_bytes)); + + if (key_len != 32 || iv_len != 16) { + fprintf(stderr, "Invalid key/IV size for AES-256\n"); + return 1; + } + + // Create socket: + int client_socket = socket(AF_INET, SOCK_STREAM, 0); + if (client_socket == -1) { + perror("Failed to create socket"); + return 1; + }else{ + printf("Socket created successfully\n"); + } + + // Send connection request to server, be sure to set por tand IP the same as server-side + struct sockaddr_in server_addr; + server_addr.sin_family = AF_INET; + server_addr.sin_port = htons(server_port); + inet_pton(AF_INET, server_ip, &server_addr.sin_addr); + + if (connect(client_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) { + perror("Failed to connect to server"); + close(client_socket); + return 1; + }else{ + printf("Connected to server successfully\n"); + } + + // Get input from the user: + printf("Enter message sent to the server (type \\quit to exit): "); + // clean the buffer + memset(client_message, 0, sizeof(client_message)); + if (fgets(client_message, sizeof(client_message), stdin) == NULL) { + // EOF or error reading from stdin, exit the loop + perror("Error reading from stdin"); + return 1; + } + + while (strcmp(client_message, "\\quit\n") != 0) { + + // Send the message to server: + // add my name in the front + char buffer[2048]; + std::snprintf(buffer, sizeof(buffer), "%s%s", custom_message, client_message); + + unsigned char ciphertext[2048]; + + int plaintext_len = (int)strlen(buffer); + int ciphertext_len = stream_encrypt((unsigned char*)buffer, plaintext_len, key_bytes, iv_bytes, ciphertext); + if (ciphertext_len <= 0) { + printf("encrypt failed or produced empty ciphertext_len=%d\n", ciphertext_len); + break; + } + + ssize_t sent = send(client_socket, ciphertext, (size_t)ciphertext_len, 0); + if (sent <= 0) { perror("No message sent to server"); break; } + + // Receive the server's response: + // add terminator for string + ssize_t recvd = recv(client_socket, server_message, sizeof(server_message) - 1, 0); + if (recvd <= 0) { perror("No message received from server"); break; } + server_message[recvd] = '\0'; + + printf("Server's response: %s\n", server_message); + + printf("Enter message sent to the server (type \\quit to exit): "); + + // clean the buffer + memset(client_message, 0, sizeof(client_message)); + memset(server_message, 0, sizeof(server_message)); + + if (fgets(client_message, sizeof(client_message), stdin) == NULL) { + // EOF or error reading from stdin, exit the loop + perror("Error reading from stdin"); + break; + } + } + + // Close the socket + close(client_socket); + + return 0; +} \ No newline at end of file diff --git a/compile.sh b/compile.sh new file mode 100755 index 0000000..f314800 --- /dev/null +++ b/compile.sh @@ -0,0 +1,30 @@ +#!/usr/bin/env bash +set -euo pipefail + +mkdir -p bin + +# add libssl-dev if needed + +# apt-get update && apt-get install -y --no-install-recommends libssl-dev + +# Adjust flags as you like +CXXFLAGS="-std=c++17 -O2 -Wall -Wextra -pedantic" +OPENSSL_LIBS="-lssl -lcrypto" + +g++ ${CXXFLAGS} server.cpp -o bin/server ${OPENSSL_LIBS} +g++ ${CXXFLAGS} client.cpp -o bin/client ${OPENSSL_LIBS} + +echo "Built:" +file bin/server bin/client || true + +chmod a+x bin/server bin/client + +# stop the containers and free up network resources +docker compose down --remove-orphans || true +docker network rm net-hw2 >/dev/null 2>&1 || true + +# start the containers +docker compose up -d server +docker compose run --rm -it client + +echo "Done." \ No newline at end of file diff --git a/docker-compose.yml b/docker-compose.yml new file mode 100644 index 0000000..3733727 --- /dev/null +++ b/docker-compose.yml @@ -0,0 +1,38 @@ +services: + server: + image: debian:bookworm-slim + container_name: hw2-server + working_dir: /app + env_file: + - .env + networks: + net-hw2: + ipv4_address: ${SERVER_IP} + volumes: + - ./bin/server:/usr/local/bin/server:ro + entrypoint: ["bash", "-lc", "apt-get update && apt-get install -y --no-install-recommends libstdc++6 iproute2 libssl-dev; exec stdbuf -oL -eL /usr/local/bin/server"] + + client: + image: debian:bookworm-slim + container_name: hw2-client + working_dir: /app + env_file: + - .env + networks: + net-hw2: + ipv4_address: ${CLIENT_IP} + depends_on: + - server + stdin_open: true + tty: true + volumes: + - ./bin/client:/usr/local/bin/client:ro + entrypoint: ["bash", "-lc", "apt-get update && apt-get install -y --no-install-recommends libstdc++6 iproute2 libssl-dev; exec stdbuf -oL -eL /usr/local/bin/client"] + +networks: + net-hw2: + name: net-hw2 + driver: bridge + ipam: + config: + - subnet: ${NET_SUBNET} diff --git a/latex/H2_CSE4303_ZheyuanWu.out b/latex/H2_CSE4303_ZheyuanWu.out new file mode 100644 index 0000000..e69de29 diff --git a/latex/H2_CSE4303_ZheyuanWu.pdf b/latex/H2_CSE4303_ZheyuanWu.pdf new file mode 100644 index 0000000..ef0ec65 Binary files /dev/null and b/latex/H2_CSE4303_ZheyuanWu.pdf differ diff --git a/latex/H2_CSE4303_ZheyuanWu.tex b/latex/H2_CSE4303_ZheyuanWu.tex new file mode 100644 index 0000000..dc2a52c --- /dev/null +++ b/latex/H2_CSE4303_ZheyuanWu.tex @@ -0,0 +1,148 @@ +\documentclass[11pt]{article} +\usepackage{amsmath, amsfonts, amsthm} +\usepackage{amssymb} +\usepackage{fancyhdr,parskip} +\usepackage{fullpage} +\usepackage{mathrsfs} +\usepackage{mathtools} + +\usepackage{float} + +% code listing +\usepackage{listings} +\usepackage{xcolor} +\lstset{% + language=c++, + breaklines=true, + commentstyle=\color{green}, % comment style + escapeinside={\%*}{*)}, % if you want to add LaTeX within your code + keywordstyle=\color{blue}, % keyword style + stringstyle=\color{purple}, % string literal style +} + +%% +%% Stuff above here is packages that will be used to compile your document. +%% If you've used unusual LaTeX features, you may have to install extra packages by adding them to this list. +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + +\setlength{\headheight}{15.2pt} +\setlength{\headsep}{20pt} +\pagestyle{fancyplain} + +%% +%% Stuff above here is layout and formatting. If you've never used LaTeX before, you probably don't need to change any of it. +%% Later, you can learn how it all works and adjust it to your liking, or write your own formatting code. +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%%%%%%%%%%%%%%%%%%%%%% +% These commands create theorem-like environments. +\newtheorem{theorem}{Theorem} +\newtheorem{lemma}[theorem]{Lemma} +\newtheorem{corollary}[theorem]{Corollary} +\newtheorem{prop}[theorem]{Proposition} +\newtheorem{defn}[theorem]{Definition} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% This section contains some useful macros that will save you time typing. +%% + +% Using \displaystyle (or \ds) in a block of math has a number of effects, but most notably, it makes your fractions come out bigger. +\newcommand{\ds}{\displaystyle} + +% These lines are for displaying integrals; typing \dx will make the dx at the end of the integral look better. +\newcommand{\is}{\hspace{2pt}} +\newcommand{\dx}{\is dx} + +% These commands produce the fancy Z (for the integers) and other letters conveniently. +\newcommand{\Z}{\mathbb{Z}} +\newcommand{\Q}{\mathbb{Q}} +\newcommand{\R}{\mathbb{R}} +\newcommand{\C}{\mathbb{C}} +\newcommand{\F}{\mathbb{F}} +\newcommand{\T}{\mathcal{T}} +\newcommand{\B}{\mathcal{B}} + +% for fancy empty set char +\renewcommand{\emptyset}{\varnothing} + +% customized commands for future assignements +\newcommand{\imply}{\Rightarrow} +\def\P{\mathscr{P}} +\def\L{\mathscr{L}} +\def\M{\mathscr{M}} +\DeclarePairedDelimiterX{\inp}[2]{\langle}{\rangle}{#1, #2} + +% url embedding +\usepackage{hyperref} + +\hypersetup{colorlinks=true,linkcolor=blue,urlcolor=blue} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% This is the header. It will appear on every page, and it's a good place to put your name, the assignment title, and stuff like that. +%% I usually leave the center header blank to avoid clutter. +%% + +\fancyhead[L]{\textbf{CSE4303 Homework 2}} +\fancyhead[C]{509191} +\fancyhead[R]{Zheyuan Wu} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + +\begin{document} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Actual math starts here! + + +% Use an enumerated list to write up problems. First we begin a list. + +\textit{Source code and detailed setup scripts are available at \url{https://git.trance-0.com/Trance-0/CSE4303H2}.} + +\begin{enumerate} +\item[1.] Description of experimental setup + +\newpage +\item[2.] Server code + +\begin{enumerate} + \item Screenshot or well-formatted copy of code + \begin{lstlisting}[language=c++] + \end{lstlisting} + \item Quick overview of what the code does in your own words. + +\end{enumerate} +\newpage + +\item[3.] Client code + +\begin{enumerate} + + \item Screenshot or well-formatted copy of code + + \begin{lstlisting}[language=c++] + \end{lstlisting} + \item Quick overview of what the code does in your own words. + + +\end{enumerate} +\newpage + + +\item[4.] Extra credits + +\newpage + +\end{enumerate} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% Actual math ends here. Don't put any content below the \end{document} line. +%% + +\end{document} diff --git a/message.txt b/message.txt new file mode 100644 index 0000000..8a3e520 --- /dev/null +++ b/message.txt @@ -0,0 +1 @@ +My password is 0214BA9480AE8D21842B80FF5287418FD0465113070FDFF8263F0F1FCD6CF030 \ No newline at end of file diff --git a/server-log.sh b/server-log.sh new file mode 100644 index 0000000..0cd26a5 --- /dev/null +++ b/server-log.sh @@ -0,0 +1 @@ +docker logs hw1-server --tail=50 \ No newline at end of file diff --git a/server.cpp b/server.cpp new file mode 100644 index 0000000..7adafcb --- /dev/null +++ b/server.cpp @@ -0,0 +1,200 @@ +#include +#include +#include +#include + +// open ssl +#include +#include +#include + +#include // for perror() +#include // for close() + +// load environment variables from .env file +#include +#include + +void load_env(const std::string& path) { + std::ifstream f(path); + std::string line; + while (std::getline(f, line)) { + if (line.empty() || line[0] == '#') continue; + auto pos = line.find('='); + if (pos == std::string::npos) continue; + + std::string key = line.substr(0, pos); + std::string val = line.substr(pos + 1); + + #ifdef _WIN32 + _putenv_s(key.c_str(), val.c_str()); + #else + setenv(key.c_str(), val.c_str(), 1); + #endif + } +} + +// hex to byte helper function +int hex_to_bytes_upper(const char* hex, unsigned char* out, size_t out_size) +{ + size_t i = 0; + while (hex[0] && hex[1]) { + if (i >= out_size) return -1; + unsigned char h = hex[0]; + unsigned char l = hex[1]; + int hi = (h <= '9') ? (h - '0') : (h - 'A' + 10); + int lo = (l <= '9') ? (l - '0') : (l - 'A' + 10); + // minimal sanity check + if (hi < 0 || hi > 15 || lo < 0 || lo > 15) + return -1; + out[i++] = (unsigned char)((hi << 4) | lo); + hex += 2; + } + return (int)i; +} + +// Define the decryption function +int block_decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key, unsigned char *iv, unsigned char *plaintext) { + /* Declare cipher context */ + EVP_CIPHER_CTX *ctx; + int len, plaintext_len; + + /* Create and initialise the context */ + ctx = EVP_CIPHER_CTX_new(); + if (!ctx) { + ERR_print_errors_fp(stderr); + } + + /* Initialise the decryption operation. */ + if (EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv) != 1){ + ERR_print_errors_fp(stderr); + } + + /* Provide the message to be decrypted, and obtain the plaintext output. EVP_DecryptUpdate can be called multiple times if necessary */ + if (EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len) != 1) { + ERR_print_errors_fp(stderr); + } + + /* Finalize the decryption. Further plaintext bytes may be written at this stage. */ + if (EVP_DecryptFinal_ex(ctx, plaintext + len, &plaintext_len) != 1) { + ERR_print_errors_fp(stderr); + } + + /* Clean up */ + EVP_CIPHER_CTX_free(ctx); + + return plaintext_len; +} + +int main(void){ + printf("Server starting...\n"); + load_env(".env"); + + // Declare variables + const char *server_ip = std::getenv("SERVER_IP"); + const int server_port = std::atoi(std::getenv("SERVER_PORT")); + char client_message[2048]; + char server_message[2048]; + const char * custom_message="Server: Hello from server, message recieved!\n"; + + // decryption parameters + const char *inital_vector = std::getenv("INITIAL_VECTOR"); + const char *secret_key = std::getenv("SECRET_KEY"); + unsigned char key_bytes[32], iv_bytes[16]; + + int key_len = hex_to_bytes_upper(secret_key, key_bytes, sizeof(key_bytes)); + int iv_len = hex_to_bytes_upper(inital_vector, iv_bytes, sizeof(iv_bytes)); + + if (key_len != 32 || iv_len != 16) { + fprintf(stderr, "Invalid key/IV size for AES-256\n"); + return 1; + } + + // debug + printf("Server starting at IP: %s, Port: %d\n", server_ip, server_port); + + // Create socket + const int server_socket = socket(AF_INET, SOCK_STREAM, 0); + if (server_socket == -1) { + perror("Failed to create socket"); + return 1; + } + + // Bind to the set port and IP + struct sockaddr_in server_addr; + server_addr.sin_family = AF_INET; + server_addr.sin_port = htons(server_port); + inet_pton(AF_INET, server_ip, &server_addr.sin_addr); + + if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) { + perror("Failed to bind socket"); + close(server_socket); + return 1; + } + printf("Done with binding with IP: %s, Port: %d\n", server_ip, server_port); + + // Listen for clients: + const char *client_ip = std::getenv("CLIENT_IP"); + if (listen(server_socket, 1) == -1) { + perror("Failed to listen on socket"); + close(server_socket); + return 1; + } + printf("Listening for incoming connections...\n"); + + // Accept an incoming connection + struct sockaddr_in client_addr; + socklen_t client_addr_len = sizeof(client_addr); + int client_socket = accept(server_socket, (struct sockaddr*)&client_addr, &client_addr_len); + if (client_socket == -1) { + perror("Failed to accept connection"); + close(server_socket); + return 1; + } + printf("Client connected at IP: %s \n", client_ip); + + // clean exising buffer + memset(client_message, 0, sizeof(client_message)); + + // Receive client's message + while (1) { + // clean exising buffer + memset(client_message, 0, sizeof(client_message)); + + ssize_t n = recv(client_socket, client_message, sizeof(client_message), 0); + if (n == 0) break; + if (n < 0) { perror("recv"); break; } + + // decrypt client message + unsigned char plaintext[2048]; + int plaintext_len = stream_decrypt((unsigned char*)client_message, (int)n, key_bytes, iv_bytes, plaintext); + if (plaintext_len < 0) { + fprintf(stderr, "decrypt failed\n"); + break; + } + + if (plaintext_len >= (int)sizeof(plaintext)) plaintext_len = (int)sizeof(plaintext) - 1; + plaintext[plaintext_len] = '\0'; + + if (strcmp((char*)plaintext, "\\exit\n") == 0) break; + + printf("Msg from client: %s", plaintext); + + // Respond to client + // prepare server message + memcpy(server_message, custom_message, strlen(custom_message)); + + size_t reply_len = strlen(server_message); + if (send(client_socket, server_message, reply_len, 0) == -1) { + perror("Send failed"); + break; + } + + printf("Response sent to client: %s\n", server_message); + } + // Close the socket + close(client_socket); + close(server_socket); + + return 0; +} \ No newline at end of file