initial pow work

package.json

@@ -26,6 +26,7 @@
     "@tbd54566975/dwn-sdk-js": "0.2.4",
     "@tbd54566975/dwn-sql-store": "0.2.1",
     "better-sqlite3": "^8.5.0",
+    "body-parser": "^1.20.2",
     "bytes": "3.1.2",
     "cors": "2.8.5",
     "express": "4.18.2",

src/http-api.ts

@@ -22,6 +22,7 @@ import {
 
 import { jsonRpcApi } from './json-rpc-api.js';
 import { requestCounter, responseHistogram } from './metrics.js';
+import { getChallenge, verifyChallenge } from './pow.js';
 
 export class HttpApi {
   #api: Express;
@@ -47,6 +48,7 @@ export class HttpApi {
 
   #setupMiddleware(): void {
     this.#api.use(cors({ exposedHeaders: 'dwn-response' }));
+    this.#api.use(express.json());
 
     this.#api.use(
       responseTime((req: Request, res: Response, time) => {
@@ -181,6 +183,9 @@ export class HttpApi {
         return res.json(jsonRpcResponse);
       }
     });
+
+    this.#api.get('/register', getChallenge);
+    this.#api.post('/register', verifyChallenge);
   }
 
   #listen(port: number, callback?: () => void): void {

src/pow.ts

@@ -0,0 +1,40 @@
+import { createHash } from 'crypto';
+import type { Request, Response } from 'express';
+
+const outstandingHashes: { [challenge: string]: Date } = {};
+
+export async function getChallenge(
+  _req: Request,
+  res: Response,
+): Promise<void> {
+  // sign a JWT with an expiration date shortly in the future (1-2 min) and a complexity
+  // make the complexity go up when get challenge requests increase in frequency
+
+  res.status(500).json({ error: 'unimplemented' });
+}
+
+export async function verifyChallenge(
+  req: Request,
+  res: Response,
+): Promise<void> {
+  console.log(req.body);
+  const body: {
+    challenge: string;
+    response: string;
+  } = req.body;
+
+  const hash = createHash('sha1');
+  hash.update(body.challenge);
+  hash.update(body.response);
+
+  const hex = hash.digest('hex');
+  const complexity = Object.keys(outstandingHashes).length;
+  for (let i = 0; i < complexity; i++) {
+    if (hex[i] != '0') {
+      res.status(401).json({ success: false });
+      return;
+    }
+  }
+
+  res.json({ success: true });
+}