1 files changed, 94 insertions, 23 deletions

diff --git a/haunt/static/js/proof-of-work.js b/haunt/static/js/proof-of-work.js
index 5207ac6..1a57c2a 100644
--- a/haunt/static/js/proof-of-work.js
+++ b/haunt/static/js/proof-of-work.js
@@ -1,34 +1,105 @@
-const text = 'An obscure body in the S-K System, your majesty. The inhabitants refer to it as the planet Earth.';
+/*
+ * proof-of-work.js -- Alternative captcha based on SHA-256 proof-of-work.
+ * Copyright © 2022 Jakob L. Kreuze <zerodaysfordays@sdf.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
 
 function makeid(length) {
-    var result           = '';
-    var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
-    var charactersLength = characters.length;
-    for ( var i = 0; i < length; i++ ) {
-        result += characters.charAt(Math.floor(Math.random() * charactersLength));
-    }
-    return result;
+  let result = '';
+  let alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
+  for (let i = 0; i < length; i++) {
+    result += alphabet.charAt(Math.floor(Math.random() * alphabet.length));
+  }
+  return result;
 }
 
 async function digestMessage(message) {
-  const msgUint8 = new TextEncoder().encode(message);                           // encode as (utf-8) Uint8Array
-  const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);           // hash the message
-  const hashArray = Array.from(new Uint8Array(hashBuffer));                     // convert buffer to byte array
-  const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join(''); // convert bytes to hex string
+  const msgUtf8 = new TextEncoder().encode(message);
+  const hashBuffer = await crypto.subtle.digest('SHA-256', msgUtf8);
+  const hashArray = Array.from(new Uint8Array(hashBuffer));
+  const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join('');
   return hashHex;
 }
 
-const HARDNESS = 4;
-
-async function findPrefix(challenge) {
-    while (true) {
-        let prefix = makeid(32);
-        let digestHex = await digestMessage(prefix + challenge);
-        if (digestHex.startsWith("0".repeat(HARDNESS))) {
-            return [prefix + challenge, digestHex];
-        }
+async function findPrefix(hardness, nonce) {
+  while (true) {
+    let prefix = makeid(32);
+    let digestHex = await digestMessage(prefix + nonce);
+    if (digestHex.startsWith("0".repeat(hardness))) {
+      return prefix;
     }
+  }
+}
+
+function makeRequest (method, url) {
+  return new Promise(function (resolve, reject) {
+    var xhr = new XMLHttpRequest();
+    xhr.open(method, url);
+    xhr.onload = function () {
+      if (xhr.status >= 200 && xhr.status < 300) {
+        resolve(xhr.response);
+      } else {
+        reject({
+          status: xhr.status,
+          statusText: xhr.statusText
+        });
+      }
+    };
+    xhr.onerror = function () {
+      reject({
+        status: xhr.status,
+        statusText: xhr.statusText
+      });
+    };
+    xhr.send();
+  });
 }
 
-const suffix = "p12IyPB2dZsmBHYZyaEMrR5OUxqNc5Z9Cijal+9/iuQ=";
-findPrefix(suffix).then(console.log);
+
+function raceEndpoint() {
+  return new Promise(function (resolve, reject) {
+    makeRequest("GET", "/api/challenge")
+      .then(function (data) {
+        let challengeData = JSON.parse(data);
+        findPrefix(challengeData.hardness, challengeData.nonce)
+          .then((prefix) => { resolve([prefix, challengeData["challenge-id"]]) } );
+      })
+      .catch(reject);
+  });
+}
+
+let trigger = document.getElementById("pow-trigger");
+trigger.hidden = false;
+trigger.addEventListener("click", (e) => {
+  trigger.innerHTML = "Please wait...";
+  trigger.disabled = true;
+  raceEndpoint()
+    .then((result) => {
+      let resultField = document.getElementById("captcha-alt");
+      let challengeIdField = document.getElementById("captcha-alt-id");
+      resultField.value = result[0];
+      challengeIdField.value = result[1];
+      trigger.innerHTML = "Proof-of-Work completed successfully!";
+      trigger.disabled = true;
+    })
+    .catch((err) => {
+      console.log(err);
+      trigger.innerHTML = "Proof-of-Work failed!";
+      trigger.disabled = true;
+    });
+  e.preventDefault();
+})
+