World of Wisdom

World of Wisdom is a CLI tool that allows you to get a random quote from a variety of sources.

Explanation of the solution

This solution is used Challenge–response approach to verify the client.

This approach has chosen because it is simple, secure and stateless in the implementation.

Challenge–response works as follows:

The client connects to the server.
The server generates an arbitrary random data and sends it back to the client with difficulty for proof of work.
The client uses brute-force to find the NONCE number and the DIFFICULTY condition.
Once the puzzle is solved, the client sends NONCE and computed HASH back to the server.
The server verifies the NONCE and HASH and sends the quote to the client.

Protocol implementation

The data is transmitted in gob format.

The protocol consists of two sections:

Field	Size	Description
Header	4 bytes	Contains the length of the data section
Payload	based on the header	Contains the data itself

Protocol messages

Challenge

type Challenge struct {
    Difficulty int
    Data       []byte
}

This structure is used to send the challenge to the client.

Solution

type Solution struct {
    Nonce int
    Hash  []byte
}

This structure is used to send the solution to the server.

Quote

type Quote struct {
    Text string
}

This structure is used to send the quote to the client.

Build the docker image

To build the docker image, you will need to run the following command:

make docker/build

How to run the project

To run the project, you will need to have Docker installed.
Run the following command to run the project:

make run

The output should look like this:

docker-compose up -d
[+] Running 2/2
 ✔ Network app_testapp     Created                                                                                                             0.1s
 ✔ Container app-server-1  Started                                                                                                             0.5s
docker-compose run client
[+] Running 1/0
 ✔ Container app-server-1  Running                                                                                                             0.0s

[*] Received quote: "Beware of false knowledge; it is more dangerous than ignorance"

docker-compose down
[+] Running 2/2
 ✔ Container app-server-1  Removed                                                                                                             0.1s
 ✔ Network app_testapp     Removed

How to run the tests

To run the tests, you will need to run the following command:

make test

Note: To run the tests you need installed GO locally.

shotonoff / testapp