🔐 PQrypt

Quantum-Resistant Encryption for Everyone

PQrypt is a next-generation post quantum cryptographic application that can protect your files and communications against both current and future quantum attacks. Available for Windows, macOS, Linux, and Android.

---

📥 Installation for Windows & Android (Pre-built Binaries)

🪟 Windows

1. Go to Releases
2. Download pqrypt-windows.exe
3. Double-click to run (Windows Defender may show a warning - click "More info" → "Run anyway")

📱 Android

1. Go to Releases
2. Download PQrypt.apk
3. Open the APK file on your phone
4. Allow installation from unknown sources if prompted
5. Install and open the app

---

🛠️ Build Desktop app from Source (Linux, macOS, windows)

Prerequisites

• Rust: Install from rustup.rs
• Git: For cloning the repository

For builds that use PQC (ML-KEM / HQC / SLH-DSA), PQrypt relies on a custom OpenSSL build and liboqs. This repo uses the Openssl/ folder to build and cache static libraries, but does not vendor those third-party sources. You must provide your own OpenSSL and liboqs checkouts in that folder.

Required for the build scripts:

• cmake
• ninja
• perl (OpenSSL build)

The current scripts are wired for:

• OpenSSL: 3.6.x (paths currently default to openssl-3.6.0)
• liboqs: 0.15

Expected Openssl/ layout:

• Openssl/openssl-3.6.0/ – OpenSSL 3.6.x source tree (or Openssl/openssl/ pointing to a compatible tree)
• Openssl/liboqs/ – liboqs 0.15 source checkout
• Openssl/static_libs/openssl-3.6/ – desktop OpenSSL static libs build/install prefix
• Openssl/static_libs/liboqs-0.15/ – desktop liboqs static lib build/install prefix
• Openssl/static_libs/openssl-3.6-android/ – Android OpenSSL static libs build/install prefix
• Openssl/static_libs/liboqs-0.15-android/ – Android liboqs static lib build/install prefix

Only small metadata files (like these READMEs) are included in this repository under Openssl/.

🍎 macOS

1. Install Xcode Command Line Tools:

   xcode-select --install

2. Clone:

   git clone https://github.com/GurudattaRK/PQrypt.git

3. Build Desktop (from scratch):

This builds:

• OpenSSL static libs into Openssl/static_libs/openssl-3.6/
• liboqs static libs into Openssl/static_libs/liboqs-0.15/
• the PQrypt desktop binary

PQRYPT_CLEAN=1 bash scripts/build_desktop.sh

4. Run the App:

   ./desktop/target/release/pqrypt

🐧 Linux

Linux builds from source use the same script as macOS, but require standard build tooling (gcc/g++, make, etc.).

PQRYPT_CLEAN=1 bash scripts/build_desktop.sh

🪟 Windows

Windows build-from-source uses MSYS2 (mingw64) so OpenSSL + liboqs can be built as static .a archives.

Follow these steps exactly:

1. Install MSYS2 from the official site.

2. Open the correct terminal:

• In the Windows Start Menu, search for:
  • MSYS2 MinGW 64-bit
• Open that one (important). The shell prompt should mention MINGW64.

3. Navigate to the PQrypt folder by following this:

In MSYS2, Windows locations look like this:

• C:\ becomes /c/
• D:\ becomes /d/

Example, if your folder is at C:\Users\gurudatta\Documents\GitHub\PQrypt then use below command to reach that location in MSYS2 MinGW terminal:

cd /c/Users/gurudatta/Documents/GitHub/PQrypt

Verify you are in the right place by running pwd command which would then show if you are at correct location or not (example: /c/Users/gurudatta/Documents/GitHub/PQrypt)

4. Next, install required build tools inside MSYS2. Do that by Copy pasting this whole command:

pacman -Syu && pacman -S --needed git mingw-w64-x86_64-toolchain mingw-w64-x86_64-cmake mingw-w64-x86_64-ninja mingw-w64-x86_64-make mingw-w64-x86_64-perl perl mingw-w64-x86_64-rust

5. Ensure OpenSSL uses the correct perl.

OpenSSL Configure will fail if perl is the Windows one. So, Force MSYS perl by running these commands one by one:

export PATH="/usr/bin:$PATH" && hash -r
which perl
perl -V:osname

6. Ensure Rust is using the GNU toolchain.

In MSYS2 MinGW64, Rust should be x86_64-pc-windows-gnu (not MSVC), To ensure that install and select the GNU toolchain by running these commands one by one:

rustup toolchain install stable-gnu
rustup default stable-gnu
rustc -Vv | grep host

7. Build Desktop (from scratch).

assuming you are at root of project (Example: /c/Users/gurudatta/Documents/GitHub/PQrypt), run this command and wait for it to finish (it may take a long time) :

PQRYPT_CLEAN=1 bash scripts/build_desktop.sh

📱 Build the Android app from source

Before you start You must set ANDROID_NDK_HOME (example path shown):

export ANDROID_NDK_HOME=/c/Path/To/Android/Sdk/ndk/<version>

You find this path using your installed Android Studio path. If you don't have Android studio then:

1. Install Android Studio from developer.android.com

2. Open the Project:

   • Open Android Studio
   • Select "Open an existing project"
   • Navigate to PQrypt/android/

3. Install SDK Components:

   • Open SDK Manager (Tools → SDK Manager)
   • Install Android SDK Platform 34
   • Install NDK version 25 or higher
   • Install CMake 3.22.1

4. Run build_android.sh to Build and Install:

PQRYPT_CLEAN=1 bash scripts/build_android.sh

This builds:

• OpenSSL static libs for Android into Openssl/static_libs/openssl-3.6-android/
• liboqs static libs for Android into Openssl/static_libs/liboqs-0.15-android/
• the Android debug APK, This APK file can be found in android/app/build/outputs/apk/debug/ and it can be used to install the app on Android devices.

---

🔒 Cryptographic Architecture

PQrypt is built on using 8 different cryptographic algorithms:

Asymmetric cryptography: Key Exchange & Key Encapsulation

1. ML-KEM-1024 (a.k.a Crystals-Kyber)
2. X448 (a.k.a Curve448)
3. HQC-256 (a.k.a Hamming-Quasi-Cyclic KEM)
4. SecP521R1 (a.k.a P-521)

Symmetric cryptography: File Encryption (Authenticated)

5. ChaCha20
6. AES-256-GCM (Also responsible for Ciphertext authentication)

Cryptographic Digital Signatures: Secure Signing & Authencation of data

7. SLH-DSA-SHAKE-256f (a.k.a SPHINCS+)

Cryptographic Hashing: Memory-hard secure hashing

8. Argon2id (with PBKDF2-HMAC-SHA256 fallback)

---

✨ Features

• 🛡️ Post-Quantum Secure: Resistant against quantum attacks.
• 📁 File Encryption: Encrypt any file with password or key file.
• 💬 Secure Messaging: Send encrypted text/files between devices
• 🔑 Password Generator: Generate strong passwords securely & deterministically
• 📱 Cross-Platform: Works on Android, Windows, macOS, and Linux

---

🏗️ Project Architecture

• Desktop Application (desktop/): Cross-platform GUI app for Linux, MacOS, and Windows built with Rust & Slint UI framework
• Android Application (android/): Native Android app with Kotlin fronted bridged to Rust backend using java/C++ FFI.

---

⚠️ Disclaimer

This software is provided "as is" without warranty or guarantee. While industry-standard algorithms are used & best practices are followed, no encryption or security is 100% unbreakable & no software is 100% safe. Hence, if any kind of damage or loss is caused by using this Project, software or any component of this project to anyone/any group of people then this project, App(s), or any of its contributors and creators shall not be held responsible. Always:

• Keep backups of important data
• Use strong, unique passwords
• Keep your software updated
• Don't share your encryption keys & sensitive data