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<header class="pos-absolute" style="background-color: transparent">
<a href="https://gradecoin.xyz/">
<div class="logo">
<img src="https://gradecoin.xyz/gradecoin.png" alt="logo">
Gradecoin
</div>
</a>
<nav>
<a class="nav-item subtitle-text" href="https://gradecoin.xyz/block-docs/">Blocks</a>
<a class="nav-item subtitle-text" href="https://gradecoin.xyz/transaction-docs/">Transactions</a>
<a class="nav-item subtitle-text" href="https://gradecoin.xyz/register-docs/">Register</a>
<a class="nav-item subtitle-text" href="https://gradecoin.xyz/jwt/">JWT</a>
<a class="nav-item subtitle-text" href="https://github.com/zhuowei/nft_ptr#why">why?</a>
</nav>
</header>
<div class="hero">
<section class="text-center">
<h1 class="heading-text" style="font-size: 50px">
Mine your own grades
</h1>
<h3 class="title-text">
<b style="color: deepskyblue">Gradecoin</b> is the latest cutting edge blockchain technology agile grading framework that drives organic engagement and other buzzwords, with big data mining search engine optimization
</h3>
<div>
</div>
</section>
<img class="hero-image" style="width: 45%" src="https://gradecoin.xyz/gradecoin.png">
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⇩ Learn How ⇩
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<a class="subtext" href="https://gradecoin.xyz/#welcome-to-gradecoin">Welcome to Gradecoin!</a>
</div>
<div class="toc-item">
<a class="subtext" href="https://gradecoin.xyz/#coinbase">Coinbase</a>
</div>
<div class="toc-item">
<a class="subtext" href="https://gradecoin.xyz/#public-key-signatures">Public Key Signatures</a>
</div>
<div class="toc-item">
<a class="subtext" href="https://gradecoin.xyz/#services">Services</a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#register"><small>- /register</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#transaction"><small>- /transaction</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#block"><small>- /block</small></a>
</div>
<div class="toc-item">
<a class="subtext" href="https://gradecoin.xyz/#questions">Questions</a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#this-all-sound-complicated"><small>- This all sound complicated!</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#i-found-a-bug"><small>- I found a bug!</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#i-hacked-the-server"><small>- I hacked the server!</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#submission"><small>- Submission?</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#can-my-friends-play"><small>- Can my friends play?</small></a>
</div>
<div class="toc-item-child">
<a class="subtext" href="https://gradecoin.xyz/#how-and-or-why"><small>- How and or Why?</small></a>
</div>
</div>
</div>
<div class="content text">
<div id="features" class="heading-text">Overview</div>
<h1 id="welcome-to-gradecoin">Welcome to Gradecoin!</h1>
<p>Blockchains are incredibly simple yet can appear very complicated, we will see how they work and practice programming <em>production</em> cryptography code.</p>
<p>This server is the sandbox for the PA1, it's 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.</p>
<p><strong>A quick summary</strong>: authenticate yourself to the system using public key encryption.
Craft <a href="https://gradecoin.xyz/transaction-docs/">Transaction</a> proposals and tag them using <a href="https://gradecoin.xyz/jwt/">JWTs</a>.
When there are enough transactions then you can propose <a href="https://gradecoin.xyz/block-docs/">Blocks</a> in the same way.
Blocks need to be <em>mined</em> beforehand using Proof-of-work, or brute force.</p>
<p>Gradecoin offers 3 endpoints at <a href="/register">/register</a>, <a href="/block">/block</a> and <a href="/transaction">/transaction</a>. You can only send GET requests to /block and /transaction without authorization.
The server is programmed in <a href="https://www.service-architecture.com/articles/web-services/representational_state_transfer_rest.html">RESTful</a> architecture, there are no <code>DELETE</code>, <code>PUT</code> or <code>UPDATE</code> operations, though.</p>
<p>Gradecoin uses a Proof-of-work block accepting mechanism. It uses single round <a href="https://www.blake2.net/">Blake2s</a> hashing which produces 256-bit (64 hexadecimal characters) output. The <a href="https://wiki.bitcoinsv.io/index.php/Target">target</a> hash is <em>24 bits</em> or <em>6 hexadecimal characters</em> of 0. During testing, I could mine a block on average around 2-7 minutes.</p>
<blockquote>
<p>We're expecting you to use existing tools and implementations. Standards are hard. <a href="https://www.reddit.com/r/crypto/comments/2coqsy/dont_roll_your_own/">Don't roll your own crypto</a>. Feel free to ask questions. Collaborate.</p>
</blockquote>
<p>You might ask,</p>
<blockquote>
<p>But if nobody has any Gradecoin then how do we have transactions?</p>
</blockquote>
<p>There is a bank! Their public key is <code>31415926535897932384626433832795028841971693993751058209749445923</code> and they have some amount of Gradecoin preloaded. It's also the only account that you can send transactions requests <em>to</em> yourself.</p>
<h1 id="coinbase">Coinbase</h1>
<p>The first transactions of a block is called the <code>coinbase</code>. They are the <strong>author</strong> of the block proposal and if the block is accepted then they get compensated for their efforts with some Gradecoin.</p>
<h1 id="public-key-signatures">Public Key Signatures</h1>
<p>Gradecoin uses 2048 bit RSA keyspairs.</p>
<h1 id="services">Services</h1>
<h2 id="register">/register</h2>
<ul>
<li>Student creates their own 2048 bit RSA <code>keypair</code></li>
<li>Downloads <code>Gradecoin</code>'s Public Key from <a href="https://odtuclass.metu.edu.tr/my/">Moodle</a></li>
<li>Encrypts their JSON wrapped <code>Public Key</code>, <code>Student ID</code> and one time <code>passwd</code> using Gradecoin's Public Key</li>
<li>Their public key is now in our database and can be used to sign their JWT's during requests</li>
</ul>
<h2 id="transaction">/transaction</h2>
<ul>
<li>You can offer a <a href="/transaction">Transaction</a> - POST request
<ul>
<li>The request should have <code>Authorization</code></li>
<li>The request header should be signed by the Public Key of the <code>by</code> field in the transaction</li>
</ul>
</li>
<li>fetch the list of <code>Transaction</code>s - GET request</li>
</ul>
<h2 id="block">/block</h2>
<ul>
<li>offer a [<code>schema::Block</code>] - POST request
<ul>
<li>The request should have <code>Authorization</code></li>
<li>The [<code>schema::Block::transaction_list</code>] of the block should be a subset of [<code>schema::Db::pending_transactions</code>]</li>
</ul>
</li>
<li>fetch the last accepted [<code>schema::Block</code>] - GET request</li>
</ul>
<p><code>Authorization</code>: The request header should have Bearer JWT.Token signed with Student Public Key</p>
<h1 id="questions">Questions</h1>
<h2 id="this-all-sound-complicated">This all sound complicated!</h2>
<ul>
<li>I've drawn inspiration from <a href="https://explorer.bitcoin.com/btc">actual Bitcoin transactions</a> and <a href="https://github.com/seanmonstar/warp/blob/master/examples/todos.rs">warp</a>. The simplicity of the system is how little interfaces it has.</li>
<li>Don't know where to start? Gradecoin uses RESTful API; simple <code>curl</code> commands or even your browser will work! <a href="https://curl.trillworks.com/">This website can help as well</a>.</li>
<li><a href="https://jwt.io">JWT Debugger</a> and the corresponding <a href="https://tools.ietf.org/html/rfc7519">RFC</a></li>
<li>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 a RSA keypair?</li>
</ul>
<h2 id="i-found-a-bug">I found a bug!</h2>
<p>Thank you! Please <a href="mailto:yigit@ceng.metu.edu.tr">let me know</a> so we can solve it.</p>
<h2 id="i-hacked-the-server">I hacked the server!</h2>
<p>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.</p>
<h2 id="submission">Submission?</h2>
<p>At the end of the <em>simulation</em>, your Gradecoin balance will be your grade. I will also expect a unique client programmed in either;</p>
<ul>
<li>c</li>
<li>c++</li>
<li>perl</li>
<li>rust</li>
<li>python</li>
<li>random assortment of bash scripts</li>
</ul>
<p>If your favourite programming language is missing please let me know 🤷?</p>
<h2 id="can-my-friends-play">Can my friends play?</h2>
<p>Sadly, no. Student's who are enrolled to the class will receive one-time-passwords for authentication.</p>
<h2 id="how-and-or-why">How and or Why?</h2>
<ul>
<li><a href="https://xkcd.com/2314/">Built</a>, <a href="https://lofi.cafe/">with</a> <a href="https://xkcd.com/2418/">Rust</a></li>
</ul>
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Built For ⁂ CENG489 ⁂ Introduction to Computer Security
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