Merkle File Bank

A CLI tool for running and using a merkle-based file storage service. The project is entirely developed in Go.

This project was developed within a 7-day coding challenge.

Features:

• The Merkle tree generation code is inspired from OpenZeppelin's implementation.
• Client-Server communications use google RPC (gRPC) and Protobuf.
• Data is stored within a simple filesystem-based directory tree, using Protobuf for serialization.
• Files are encrypted in AES-GCM-128 before upload to server.
• Each filebank is identified by an Ed25519 private key, encrypted and stored in pkcs8 DER format.
• Each bank is protected by a passphrase that is used to decrypt the ed25519 private key, and seeds a PBKDF2 function to generate one distinct AES encryption key for each file in the bank.
• Authentication of banks is based on a simple signature challenge-response scheme.
• All communication is encrypted and authenticated using server-side SSL/TLS.
• CLI is powered by Cobra.

1. Compiling

$ go build -o filebankd filebankd/main.go

2. Usage

2.1. Running server

$ filebankd start
Server key not found. Creating new key
Enter password for key: 
Re-enter password for key: 
Starting server with TLS enabled...
2023/08/18 09:47:47 Server listening on [::]:5500

2.2. Adding server to client

$ filebankd server add --address server1.filebank.fr MyServer1
Server 'MyServer1' was successfully added to known servers
$ filebankd server list
                Name                      Host
===========================================================
           MyServer1            server1.filebank.fr:5500

2.3. Creating bank on server

$ filebankd bank create -s MyServer1 -b MyBank1 ../test/ ../files/
Scanning ../test
Adding ../test/LICENSE
Scanning ../test/cmd
Adding ../test/cmd/bank.go
Adding ../test/cmd/root.go
Adding ../test/cmd/serveradd.go
Adding ../test/go.mod
Adding ../test/go.sum
Adding ../test/main.go
Scanning ../files
Adding ../files/test1.txt
Adding ../files/test2.docx
Adding ../files/test3.pdf
Adding ../files/test4
Enter password for bank: 
Re-enter password for bank: 
Bank MyServer1:MyBank1 has been succesfully created and uploaded
$ filebankd bank list -s MyServer1
Banks for server 'MyServer1'
=====================================
        MyBank1
$ filebankd bank list -s MyServer1 -b MyBank1
Files for bank 'MyServer1:MyBank1'
=====================================
    1  LICENSE
    2  bank.go
    3  root.go
    4  serveradd.go
    5  go.mod
    6  go.sum
    7  main.go
    8  test1.txt
    9  test2.docx
   10  test3.pdf
   11  test4

2.4. Pulling file from bank

$ filebankd bank pull -s MyServer1 -b MyBank1 8 
Enter bank password: 
File written to /home/filebankd/.filebankd/downloads/test1.txt
Successfully downloaded, verified and decrypted file 8 from bank MyServer1:MyBank1
$ cat /home/filebankd/.filebankd/downloads/test1.txt 
MyTest1

3. Deploying

3.1. Running containers

A Makefile and docker-compose are provided to deploy a simple testbed containing 6 containers: server1, server2, server3, client1, client2, client3.

Each instance is identified in the network by a network-alias name.filebank.fr where name is the instance's name.

Run the following commands in order :

$ make build
$ make start

3.2. Interactig with containers

Run the following command to interact with an instance. Note that name is the name of the instance in question.

$ docker-compose exec -it name bash