wireguard-tools/contrib/keygen-html/keygen.html

<script src="curve25519_generate.js" onError='document.write("<h3>Did you forget to run \"make\" to compile curve25519_generate.js?</h3><!--");'></script>
<script>
/* SPDX-License-Identifier: GPL-2.0
 *
 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

function sendPubkeyToServer(pubkey, username, password)
{
	var node = document.createElement("li");
	node.innerText = "Sending " + username + ":" + password + " to server for new pubkey " + pubkey + "...";
	document.body.appendChild(node);

	// send info to server

	var serverResponse = {
		publicKey: "6spHEFoJrp9pijbxjJoS6fHjZaAWQqtdFFO/OtpVe3w=",
		allowedIPs: [ "0.0.0.0/0", "::/0" ],
		endpoint: "demo.wireguard.com:63321",
		address: [ "192.168.18.42/32", "fd08:1234:1111::77/128" ],
		dns: [ "8.8.8.8", "8.8.4.4" ]
	}

	return serverResponse;
}

function downloadNewConfiguration()
{
	var keypair = WireGuard.generateKeypair();
	var serverResponse = sendPubkeyToServer(keypair.publicKey, "zx2c4", "supersecretpassword");

	var config = [];
	config.push("[Interface]");
	config.push("PrivateKey = " + keypair.privateKey);
	config.push("Address = " + serverResponse.address.join(", "));
	config.push("DNS = " + serverResponse.dns.join(", "));
	config.push("");
	config.push("[Peer]");
	config.push("PublicKey = " + serverResponse.publicKey);
	config.push("AllowedIPs = " + serverResponse.allowedIPs.join(", "));
	config.push("Endpoint = " + serverResponse.endpoint);
	config.push("");
	return config.join("\n");
}

function giveOneConfigurationToUser()
{
	var config = downloadNewConfiguration();
	var blob = new Blob([config], { type: "text/plain" });
	var a = document.createElement("a");
	a.download = "demo0.conf";
	a.href = URL.createObjectURL(blob);
	a.style.display = "none";
	document.body.appendChild(a);
	a.click();
	document.body.removeChild(a);
}

function putU32(b, n)
{
	b.push(n & 0xff, (n >>> 8) & 0xff, (n >>> 16) & 0xff, (n >>> 24) & 0xff);
}

function putU16(b, n)
{
	b.push(n & 0xff, (n >>> 8) & 0xff);
}

function putBytes(b, a)
{
	for (var i = 0; i < a.length; ++i)
		b.push(a[i] & 0xff);
}

function encodeString(s)
{
	var utf8 = unescape(encodeURIComponent(s));
	var b = new Uint8Array(utf8.length);
	for (var i = 0; i < utf8.length; ++i)
		b[i] = utf8.charCodeAt(i);
	return b;
}

function crc32(b)
{
	if (!crc32.table) {
		crc32.table = [];
		for (var c = 0, n = 0; n < 256; c = ++n) {
			for (var k = 0; k < 8; ++k)
				c = ((c & 1) ? (0xedb88320 ^ (c >>> 1)) : (c >>> 1));
			crc32.table[n] = c;
		}
	}
	var crc = -1;
	for (var i = 0; i < b.length; ++i)
		crc = (crc >>> 8) ^ crc32.table[(crc ^ b[i]) & 0xff];
	return (crc ^ (-1)) >>> 0;
}

function createZipFile(files)
{
	var b = [];
	var cd = [];
	var offset = 0;

	for (var i = 0; i < files.length; ++i) {
		var name = encodeString(files[i].name);
		var contents = encodeString(files[i].contents);
		var crc = crc32(contents);

		putU32(b, 0x04034b50); /* signature */
		putU16(b, 20); /* version needed */
		putU16(b, 0); /* flags */
		putU16(b, 0); /* compression method */
		putU16(b, 0); /* mtime */
		putU16(b, 0); /* mdate */
		putU32(b, crc); /* crc32 */
		putU32(b, contents.length); /* compressed size */
		putU32(b, contents.length); /* uncompressed size */
		putU16(b, name.length); /* file name length */
		putU16(b, 0); /* extra field length */
		putBytes(b, name);
		putBytes(b, contents);

		putU32(cd, 0x02014b50); /* signature */
		putU16(cd, 0); /* version made */
		putU16(cd, 20); /* version needed */
		putU16(cd, 0); /* flags */
		putU16(cd, 0); /* compression method */
		putU16(cd, 0); /* mtime */
		putU16(cd, 0); /* mdate */
		putU32(cd, crc); /* crc32 */
		putU32(cd, contents.length); /* compressed size */
		putU32(cd, contents.length); /* uncompressed size */
		putU16(cd, name.length); /* file name length */
		putU16(cd, 0); /* extra field length */
		putU16(cd, 0); /* file comment length */
		putU16(cd, 0); /* disk number start */
		putU16(cd, 0); /* internal file attributes */
		putU32(cd, 32); /* external file attributes - 'archive' bit set (32) */
		putU32(cd, offset); /* relative offset of local header */
		putBytes(cd, name); /* file name */

		offset += 30 + contents.length + name.length
	}
	putBytes(b, cd); /* central directory */
	putU32(b, 0x06054b50); /* end of central directory signature */
	putU16(b, 0); /* number of this disk */
	putU16(b, 0); /* number of disk with central directory start */
	putU16(b, files.length); /* number of entries on disk */
	putU16(b, files.length); /* number of entries */
	putU32(b, cd.length); /* length of central directory */
	putU32(b, offset); /* offset to start of central directory */
	putU16(b, 0); /* zip comment size */
	return Uint8Array.from(b);
}

function giveMultipleConfigurationsToUser()
{
	var zipFile = createZipFile([
		{ name: "demo0.conf", contents: downloadNewConfiguration() },
		{ name: "demo1.conf", contents: downloadNewConfiguration() },
		{ name: "demo2.conf", contents: downloadNewConfiguration() }
	]);
	var blob = new Blob([zipFile], { type: "application/zip" });
	var a = document.createElement("a");
	a.download = "demo-configs.zip";
	a.href = URL.createObjectURL(blob);
	a.style.display = "none";
	document.body.appendChild(a);
	a.click();
	document.body.removeChild(a);
}

</script>

<p><a href="javascript:giveOneConfigurationToUser()">Download a WireGuard configuration file</a></p>
<p><a href="javascript:giveMultipleConfigurationsToUser()">Download several WireGuard configuration files</a></p>