Added signString() method

Readme.md

@@ -56,6 +56,7 @@ This feature can be enable / disabled in Options.
 - getPublicKey()
 - signEvent(event)
 - getRelays()
+- signString()
 
 [NIP-04](https://github.com/nostr-protocol/nips/blob/master/04.md)
 

src/background/background.js

@@ -7,6 +7,10 @@ import * as nip44 from "nostr-tools/nip44";
 import { Mutex } from "async-mutex";
 import { LRUCache } from "./utils";
 
+import {sha256} from "@noble/hashes/sha256";
+import {bytesToHex} from "@noble/hashes/utils";
+import {schnorr} from "@noble/curves/secp256k1";
+
 import {
   NO_PERMISSIONS_REQUIRED,
   updatePermission,
@@ -296,6 +300,24 @@ async function handleContentScriptMessage({ type, params, host, protocol }) {
           ? event
           : { error: { message: "invalid event" } };
       }
+      case "signString": {
+        if (typeof params.message !== 'string') {
+          return { error: { message: "message is not a string" } };
+        }
+        try {
+            // Check this is not a stringified event
+            // trying to bypass permission checks
+            const obj = JSON.parse(params.message);
+            if (validateEvent(obj)){
+              return { error: { message: "use signEvent() to sign events" } };
+            }
+        } catch (e) {} // not a JSON string
+        const utf8Encoder = new TextEncoder();
+        const hash = bytesToHex(sha256(utf8Encoder.encode(params.message)));
+        const sig = bytesToHex(schnorr.sign(hash, sk));
+        const pubkey = bytesToHex(schnorr.getPublicKey(sk));
+        return {hash: hash, sig: sig, pubkey: pubkey};
+      }
       case "nip04.encrypt": {
         let { peer, plaintext } = params;
         lib = "nostr-tools/nip04";

src/common/common.js

@@ -9,6 +9,7 @@ export const PERMISSION_NAMES = {
   getPublicKey: "read your public key",
   getRelays: "read your list of preferred relays",
   signEvent: "sign events using your private key",
+  signString: "sign messages using your private key",
   "nip04.encrypt": "encrypt messages to peers",
   "nip04.decrypt": "decrypt messages from peers",
   "nip44.encrypt": "encrypt messages to peers",

src/static/nostr-provider.js

@@ -10,6 +10,10 @@ window.nostr = {
     return this._call("signEvent", { event });
   },
 
+  async signString(message) {
+    return this._call("signString", { message });
+  },
+
   async getRelays() {
     return this._call("getRelays", {});
   },