From 1f95a4f0c829436d9030501530a682d2e7841279 Mon Sep 17 00:00:00 2001
From: Danny Morabito <danny@arx-ccn.com>
Date: Sat, 22 Feb 2025 14:30:46 +0100
Subject: [PATCH] pow all notes

---
 consts.ts | 20 ++++++++++++++++++++
 index.ts  | 12 +++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 consts.ts

diff --git a/consts.ts b/consts.ts
new file mode 100644
index 0000000..cb2ce39
--- /dev/null
+++ b/consts.ts
@@ -0,0 +1,20 @@
+/**
+ * Minimum required Proof of Work (PoW) difficulty for note acceptance.
+ *
+ * Notes with PoW below this threshold will be rejected without decryption attempts.
+ * This threshold serves as a DoS protection mechanism for the CCN in case of
+ * public key compromise.
+ */
+export const MIN_POW = 8;
+
+/**
+ * Target Proof of Work (PoW) difficulty for relay-generated notes.
+ *
+ * Defines the PoW difficulty level that the relay will compute when generating
+ * and encrypting its own notes before broadcasting them to the network.
+ *
+ * Expected Performance on modern hardware (2025):
+ * - Difficulty 8: ~1ms
+ * - Difficulty 21: ~5-6 seconds
+ */
+export const POW_TO_MINE = 10;
diff --git a/index.ts b/index.ts
index 3a81e31..7cfb67a 100644
--- a/index.ts
+++ b/index.ts
@@ -20,6 +20,7 @@ import { Database } from "jsr:@db/sqlite";
 import { mixQuery, sql, sqlPartial } from "./utils/queries.ts";
 import { log, setupLogger } from "./utils/logs.ts";
 import { getEveFilePath } from "./utils/files.ts";
+import { MIN_POW, POW_TO_MINE } from "./consts.ts";
 
 await setupLogger();
 
@@ -111,6 +112,7 @@ async function createEncryptedEvent(
   const ccnPubKey = await getCCNPubkey();
   const ccnPrivateKey = await getCCNPrivateKey();
   const randomPrivateKey = nostrTools.generateSecretKey();
+  const randomPrivateKeyPubKey = nostrTools.getPublicKey(randomPrivateKey);
   const conversationKey = nip44.getConversationKey(randomPrivateKey, ccnPubKey);
   const sealTemplate = {
     kind: 13,
@@ -124,8 +126,10 @@ async function createEncryptedEvent(
     created_at: randomTimeUpTo2DaysInThePast(),
     content: nip44.encrypt(JSON.stringify(seal), conversationKey),
     tags: [["p", ccnPubKey]],
+    pubkey: randomPrivateKeyPubKey,
   };
-  const giftWrap = nostrTools.finalizeEvent(giftWrapTemplate, randomPrivateKey);
+  const minedGiftWrap = nostrTools.nip13.minePow(giftWrapTemplate, POW_TO_MINE);
+  const giftWrap = nostrTools.finalizeEvent(minedGiftWrap, randomPrivateKey);
   return giftWrap;
 }
 
@@ -138,6 +142,12 @@ async function decryptEvent(
     throw new Error("Cannot decrypt event -- not a gift wrap");
   }
 
+  const pow = nostrTools.nip13.getPow(event.id);
+
+  if (pow < MIN_POW) {
+    throw new Error("Cannot decrypt event -- PoW too low");
+  }
+
   const conversationKey = nip44.getConversationKey(ccnPrivkey, event.pubkey);
   const seal = JSON.parse(nip44.decrypt(event.content, conversationKey));
   if (!seal) throw new Error("Cannot decrypt event -- no seal");