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PCM_CCTF_challenge/flag_encoder/index.html

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implement a proper flag encoder tool as an HTML+JS app
2023-08-20 01:20:23 +00:00
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>CryptoCTF zero-knowledge flag-submission encoder v0.1</title>
add type="text/javascript" to <script>s
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<script type="text/javascript" src="bn.js"></script>
<script type="text/javascript" src="nano-ethereum-signer-mod.js"></script>
implement a proper flag encoder tool as an HTML+JS app
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</head>
<body>
<label for="inp-contestant-address">contestant's address:</label> <input id="inp-contestant-address" type="text" size="42" pattern="0x[0-9a-fA-F]{40}" required placeholder="0x0000000000000000000000000000000000000000" autocomplete="cryptocurrency address" title="The cryptocurrency address of the contestant who is submitting the flag. It will be used as the message that is signed using an ECDSA signature scheme. It is incorporated to prevent submission forgery and theft. The resulting signature will be accepted by the CCTF smart-contract from only this address."/><br/>
rewrite pattern using \{ instead of [{]
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<label for="inp-flag">flag:</label> <input id="inp-flag" type="text" size="72" pattern="CCTF\{.*\}" required placeholder="CCTF{…}" autocomplete="flag" title="The flag for the challenge in question: a piece of data that can be found through solving the problem. It can be an outstanding character sequence of the form CCTF{…} that can be stumbled upon; otherwise its location/calculation (e.g. the deciphered message) and its formatting (e.g. hexadecimal) are precisely specified, and formatting always includes enclosing by CCTF{…}. The flag will be used as the secret key for signing using an ECDSA signature scheme." accesskey="f"/> <label for="outp-obscured-flag">⇒ obscured flag: </label><input id="outp-obscured-flag" type="text" size="42" readonly title="The obscured flag: data to allow zero-knowledge verification of knowledge of the flag. It is the elliptic-curve public key related to the flag as the private key. It is the thing to be loaded into the CCTF smart-contract for the respective challenge."/><br />
implement a proper flag encoder tool as an HTML+JS app
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<label for="outp-signature">⇒ signature: </label><input id="outp-signature" type="text" size="132" readonly title="The signature: a zero-knowledge proof of knowledge of the flag, bound to the given address. It's an ECDSA signature of the address as the message (hash) with the flag as the key. It is to be passed to the CCTF smart-contract's flag submission function."/><!--<br />
<label for="inp-contract-address">CCTF smart-contract address:</label> <input id="inp-contract-address" type="text" size="42" pattern="0x[0-9a-fA-F]{40}" placeholder="0x0000000000000000000000000000000000000000"/><br/>
<label for="inp-contest-id">contest ID:</label> <input id="inp-contest-id" type="text" size="66" pattern="0x[0-9a-fA-F]+|[0-9]+" placeholder="0x0000000000000000000000000000000000000000000000000000000000000000"/><br/>
<label for="inp-challenge-id">challenge ID:</label> <input id="inp-challenge-id" type="integer" size="4" placeholder="0" accesskey="c"/>-->
add type="text/javascript" to <script>s
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<script type="text/javascript">
implement a proper flag encoder tool as an HTML+JS app
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var inpContestantAddress = document.querySelector("#inp-contestant-address");
var inpFlag = document.querySelector("#inp-flag");
var outpObscuredFlag = document.querySelector("#outp-obscured-flag");
var outpSignature = document.querySelector("#outp-signature");
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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var secp256k1n = new BN('115792089237316195423570985008687907852837564279074904382605163141518161494337', 10);
implement a proper flag encoder tool as an HTML+JS app
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properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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function getPrivateKey() {
var s = inpFlag.value;
var k = new BN(0);
var h = "0x";
for (i in s) {
var c = s.charCodeAt(i);
k = k.muln(16).addn(c);
h += c.toString(16).padStart(2, "0");
implement a proper flag encoder tool as an HTML+JS app
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}
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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if (k.mod(secp256k1n).eqn(0)) {
return null;
implement a proper flag encoder tool as an HTML+JS app
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}
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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return h;
implement a proper flag encoder tool as an HTML+JS app
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}
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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function updateOutputValues(ev) {
var k = getPrivateKey();
if (k === null) {
outpObscuredFlag.value = "";
implement a proper flag encoder tool as an HTML+JS app
2023-08-20 01:20:23 +00:00
outpSignature.value = "";
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
2023-11-22 19:10:27 +00:00
} else {
outpObscuredFlag.value = addressFromKey(k);
var m = inpContestantAddress.value;
if (m.slice(0, 2) !== "0x") {
outpSignature.value = "";
} else {
outpSignature.value = signMessage(m, k);
}
implement a proper flag encoder tool as an HTML+JS app
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}
}
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
2023-11-22 19:10:27 +00:00
inpContestantAddress.oninput = updateOutputValues;
inpFlag.oninput = updateOutputValues;
implement a proper flag encoder tool as an HTML+JS app
2023-08-20 01:20:23 +00:00
properly handle the case where the (flag-derived) key is invalid (e.g., namely, unpopulated field) this practically rewrites the JavaScript code in the index.html file now the tool works without manual intervention
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updateOutputValues();
implement a proper flag encoder tool as an HTML+JS app
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</script>
</body>
</html>