Secure Cloud Storage

University Project for "Foundations of Cybersecurity" course (MSc Computer Engineering @ University of Pisa). Implementation of a Secure Cloud Storage using C++ 17 and OpenSSL 1.1.1 library.

Overview

The project consists of a secure cloud storage. Each client connects to a centralized server that allows to perform operations on its private dedicated storage. In order to access to his storage, a user must login, after that he can execute the following operations:

• List: shows all files currently on the storage
• Download: retrieves a file from the storage to the local file system
• Upload: loads a file from the local file system to the storage
• Rename: changes the name of a file on the storage
• Delete: removes a file from the storage
• Logout: closes the connection to the server

The login operation creates a secure connection between the server and a client through the negotiation of a set of session keys.

The cloud storage application has to guarantee the following requirements:

• The key negotiation has to provide the Perfect Forward Secrecy
• The client and server communication has to be encrypted and authenticated
• The client and server communication has to be protected against reply attacks

Client and server authenticate each other using their own public keys. The server already knows all the registered users’ keys and the client retrieves the server’s key through the certificate released by a Certification Authority.

Getting Started

In order to compile the project, openssl-1.1.1 is needed with the development library:

sudo apt install libssl-dev 

To compile the project:

mkdir bin
make

To run the project:

bin/server
bin/client

Project Architecture

Secure-Cloud-Storage
├── data
│   ├── biagio
│   ├── gianluca
│   └── matteo
├── docs
├── resources
│   ├── certificates
│   ├── Config.h
│   ├── encrypted_keys
│   ├── private_keys
│   └── public_keys
├── script
└── src
    ├── client
    ├── packet
    ├── security
    ├── server
    └── utility

Authors

• Biagio Cornacchia, b.cornacchia@studenti.unipi.it
• Gianluca Gemini, g.gemini@studenti.unipi.it
• Matteo Abaterusso, m.abaterusso@studenti.unipi.it