From 0e61ab8ccc553e1420efc31941d2fa4cb986eb3f Mon Sep 17 00:00:00 2001
From: sachaaaaa <sacha@loki.network>
Date: Thu, 8 Aug 2019 13:44:46 +1000
Subject: [PATCH] Better document magic numbers

---
 libtextsecure/account_manager.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libtextsecure/account_manager.js b/libtextsecure/account_manager.js
index 98621fba1..db0c9192a 100644
--- a/libtextsecure/account_manager.js
+++ b/libtextsecure/account_manager.js
@@ -523,7 +523,10 @@
       });
     },
     async generateMnemonic(language = 'english') {
-      const seed = window.Signal.Crypto.getRandomBytes(16);
+      // Note: 4 bytes are converted into 3 seed words, so length 12 seed words
+      // (13 - 1 checksum) are generated using 12 * 4 / 3 = 16 bytes.
+      const seedSize = 16;
+      const seed = window.Signal.Crypto.getRandomBytes(seedSize);
       const hex = StringView.arrayBufferToHex(seed);
       return mnemonic.mn_encode(hex, language);
     },