From d1b2b07ca94d409475d341a5756921f9a0715f80 Mon Sep 17 00:00:00 2001
From: Daniel McNally <mcnallydp@gmail.com>
Date: Thu, 17 Aug 2023 18:39:42 +0000
Subject: [PATCH] Improve error message for invalid privkey length

This adds detail to the error message when a Uint8Array is provided as
a privkey but it does not have the correct length. Previously, the error
message stated only "Uint8Array expected" - which is confusing because a
Uint8Array was in fact provided. This should make debugging invalid
privkeys easier.

A test case is added that checks for the new error message.
---
 index.js             | 2 +-
 index.ts             | 2 +-
 test/ed25519.test.js | 4 ++++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/index.js b/index.js
index 121220f..823e69d 100644
--- a/index.js
+++ b/index.js
@@ -12,7 +12,7 @@ const err = (m = '') => { throw new Error(m); }; // error helper, messes-up stac
 const str = (s) => typeof s === 'string'; // is string
 const au8 = (a, l) => // is Uint8Array (of specific length)
  !(a instanceof Uint8Array) || (typeof l === 'number' && l > 0 && a.length !== l) ?
-    err('Uint8Array expected') : a;
+    err('Uint8Array of valid length expected') : a;
 const u8n = (data) => new Uint8Array(data); // creates Uint8Array
 const toU8 = (a, len) => au8(str(a) ? h2b(a) : u8n(a), len); // norm(hex/u8a) to u8a
 const mod = (a, b = P) => { let r = a % b; return r >= 0n ? r : b + r; }; // mod division
diff --git a/index.ts b/index.ts
index aaa0214..93dc415 100644
--- a/index.ts
+++ b/index.ts
@@ -13,7 +13,7 @@ const err = (m = ''): never => { throw new Error(m); }; // error helper, messes-
 const str = (s: unknown): s is string => typeof s === 'string'; // is string
 const au8 = (a: unknown, l?: number): Bytes =>          // is Uint8Array (of specific length)
   !(a instanceof Uint8Array) || (typeof l === 'number' && l > 0 && a.length !== l) ?
-  err('Uint8Array expected') : a;
+  err('Uint8Array of valid length expected') : a;
 const u8n = (data?: any) => new Uint8Array(data);       // creates Uint8Array
 const toU8 = (a: Hex, len?: number) => au8(str(a) ? h2b(a) : u8n(a), len);  // norm(hex/u8a) to u8a
 const mod = (a: bigint, b = P) => { let r = a % b; return r >= 0n ? r : b + r; }; // mod division
diff --git a/test/ed25519.test.js b/test/ed25519.test.js
index f034ff8..e83e3fc 100644
--- a/test/ed25519.test.js
+++ b/test/ed25519.test.js
@@ -29,6 +29,10 @@ describe('ed25519', () => {
       100000000000000000000000000000000000009000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000090000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800073278156000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000n;
     throws(() => ed.getPublicKey(invalidPriv));
   });
+  should('not accept >32byte private keys in Uint8Array format', () => {
+    const invalidPriv = new Uint8Array(33);
+    throws(() => ed.getPublicKey(invalidPriv), new Error('Uint8Array of valid length expected'));
+  });
   should('verify recent signature', () => {
     fc.assert(
       fc.property(