Welcome to Gradecoin!

Blockchains are incredibly simple, but they can seem very complicated. We will see how they work and practice programming production grade cryptography code.

This server is the sandbox for PA1, and it is currently running the Gradecoin application. Gradecoin is the faux currency we will use to simulate a blockchain network. At the end of the simulation, the amount of Gradecoin you hold will be your PA1 grade.

A quick summary: authenticate yourself to the system using public key encryption. Craft Transaction proposals and tag them using JWTs. When there are enough transactions then you can propose Blocks. Blocks need to be mined beforehand using Proof-of-work a.k.a. brute force.

Gradecoin uses a Proof-of-work block accepting mechanism. It uses single round Blake2s hashing which produces 256-bit (64 hexadecimal characters) output. The target hash is 24 bits or 6 hexadecimal characters of 0.

We're expecting you to use existing tools and implementations. Don't roll your own crypto. Feel free to ask questions. Collaborate.

You need to authenticate yourself to Gradecoin to begin with, and get rewarded for your hard work with some Gradecoin to start with! Then you can earn block rewards by proposing blocks, create some Gradecoins by generating traffic on the system, or transact with our new highly trained AI bots!

Coinbase

The first transactions of a block is called the coinbase. They are the author of the block proposal and if the block is accepted then they get compensated for their efforts with some Gradecoin.

Public Key Signatures

Gradecoin uses 2048-bit RSA key pairs.

Services

Please respect the system and others. Keep your request rate below a reasonable limit. Programming a bot is absolutely fine as long as it's not aggressively sending requests.

/register

• Create your own 2048-bit RSA keypair
• Download Gradecoin's public key from ODTUClass
• Encrypt your JSON wrapped Public Key, Student ID and one time passwd using Gradecoin's public key
• Your public key is now in the database. You can use your private key to sign your JWTs during requests
• Don't forget your public key
• For more information, check the register page

/transaction

• You can offer a Transaction with a POST request
  • The request should have Authorization
  • The request header should be signed by the private key of the source field in the transaction
• Fetch the list of Transactions with a GET request
• For more information, check our transaction page

/block

• Offer a Block with a POST request
  • The request should have Authorization
  • The transaction_list of the block should be a subset of pending transactions, available on /transaction
• Fetch the last accepted Block with a GET request
• For more information, check our block page

Authorization: The request header should have Bearer JWT.Token signed with student's private key

/user

• Looking for people to conduct business with? Everyone is listed on this page! 🤖👋 are bots who are very eager to transact with you. I've trained them personally using state-of-the-art neural networks running on thousands of TPUs.

/config

• Making a GET request to this auxiliary endpoint will provide the current configuration of the Gradecoin network in JSON form.
• The information about the individual fields can be found in the misc Page.

/version

• Shows the current version of Gradecoin.
• You can use this to compare the live version to the version on GitHub.

Questions

This all sound complicated!

• I've drawn inspiration from actual Bitcoin transactions and warp. The system has only 3 interfaces. It's simple once you read everything over a couple of times.
• Don't know where to start? Gradecoin uses RESTful API; simple curl commands or even your browser will work! This website can help as well.
• Check out JWT Debugger and the corresponding RFC.
• Remember that you are absolutely encouraged to grab off-the-shelf implementations for every cryptography primitive you will use. You can start by finding a code snippet to generate an RSA key pair?
• Check out misc for everything else you might be curious about.

How do you actually earn Gradecoin?

• Register yourself to at /register
• Create transactions at /transaction
• Create blocks to commit transactions at /block
• See how everyone is doing and find people to trade with at /user

I found a bug!

Thank you! Please let me know so we can solve it.

I hacked the server!

That wasn't supposed to happen 😢. I did not place any intentional vulnerabilities to the system so if you cracked something, it was not intended. Please don't abuse it and let me know, so I can patch it.

I want to contribute!

Thank you! The code for Gradecoin and this site are open source, so you can take a look and let me know if you have any improvements, corrections, typos to point out or whatever. Both documentation (this site) and code contributions are appreciated. My git server will be somewhat ahead of the GitHub repository, but I will sync them at every major milestone.

Submission?

At the end of the simulation, your Gradecoin balance will be your grade. I will also expect your client for submission, programmed in either;

• c
• c++
• dart/typescript
• go
• perl
• python
• random assortment of bash scripts
• rust

If your favourite programming language is missing please let me know 🤷?

How and or Why?

• Built, with Rust