This is a simple implementation for PoW algorithm, can be used for some study purposes, but not for production code. A lot of required things for production code are missed. Project contains:
- PoW server, it returns one random quote if client resolves challenge.
- PoW Client library
- Sample client using pow client library
1 ----request service--->
2 <---challenge----------
3 Client ----solved challenge--> Server
4 <---qoute--------------
5 <---close connection---
- Client creates a connection to the server.
- Server generates a challenge and sends it back to the client. Server adds difficulty value to the end of response.
- Client finds a solution for provided challenge and send to the server.
- Server checks the solution and if it's correct return random quote.
- Server closes the connection.
Challenge packet consist three parts - total packet length (one byte, this byte isn't used in calculation), challenge (some random string) and difficulty (one byte, how many leading zeros is accepted by server)
| Name | Length | Sample |
|---|---|---|
| Packet size | 1 | 14 |
| Challenge | various | []byte("hello, world!") |
| Difficulty | 1 | 20 |
Solution packet has three logical blocks: packet length, solution, suffix. Solution equals to sha(challenge+prefix) start with at least difficulty zeros in binary interpretation
| Name | Length | Sample |
|---|---|---|
| Packet size | 1 | 24 |
| Solution | 20 | [20]byte{...} |
| Suffix | various | []byte{0,5,0,0} |
Client library can be used only in Go lang project. To create PoW connection use
// Dial(network, address string) (net.Conn, error)
client.GetPoWClient().Dial("tcp", "%SERVER_HOST%:%SERVER_PORT%")
Connection will be ready to use after this. When connection is returned, all verification has already finished.
Simple UUID v4 is used for random string generation, but it can be updated to other algorithm without client changes. Also text file data/quotes.txt is used as quotes storage for response after success verification process.
- cmd/client - client main file, it's just a sample of using of PoW client library
- cmd/server - server main file
- data/quotes - sample quotes storage file
- internal/server - server codebase
- internal/utils - some helper functions used in client and server
- pkg/client - client library, can be used in other projects
- docker-compose
make server-linux-build
Compile server for Docker
make client-linux-build
Compile client for Docker
make start-server
Compile and start server in a Docker container
make start-client
Compile and start client in a Docker container
make test
Run unit tests
...
Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
Recreating pow_test_server_1 ... done
Attaching to pow_test_server_1
server_1 | server is started
server_1 | got a client!
server_1 | challenge sent!
server_1 | all is ok, access is granted!
server_1 | access is granted! sending a quote
Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them
pow_test_server_1 is up-to-date
Recreating pow_test_client_1 ... done
Attaching to pow_test_client_1
client_1 | We got something from the server: If you are not willing to risk the usual you will have to settle for the ordinary. ~Jim Rohn
pow_test_client_1 exited with code 0