From 05ca2c2c55a73d3beb15282923f69da66ede1cfc Mon Sep 17 00:00:00 2001
From: Matthew Zipkin <pinheadmz@gmail.com>
Date: Mon, 14 Mar 2022 13:17:50 -0400
Subject: [PATCH] Fix: addresses being derived from change branch instead of
 receive

---
 build/hip2-server.js | 15 +++++++++++++--
 src/derive.js        | 15 +++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/build/hip2-server.js b/build/hip2-server.js
index 5209dc3..4c0cd07 100644
--- a/build/hip2-server.js
+++ b/build/hip2-server.js
@@ -33,18 +33,29 @@ if (xpub === 'xpub6DBMpym6PM3qe7Ug7BwG6zo7dinMMjpk8nmb73czsjkzPTzfQ1d5ZvqDea4uNm
   throw new Error('Example xpub must not be used! Repalce with your own account xpub.');
 
 const acct = HDPublicKey.fromBase58(xpub);
+
+// For some reason when bpkg'ed with -browser modules, we need to call
+// this once as a throwaway before actually using it.
+// The first function call FAILS because entropy can not be found to
+// "pregenerate a random blinding value" as part of the ECDSA precomputation.
+// For whatever reason, the function call succeeds from here on.
+// This is either a bug in bcrypto or bpkg, exposing an inconguity
+// with the -browser module.
+// See https://github.com/handshake-org/hsd/issues/700
+acct.derive(0);
+
 const recv = acct.derive(0);
 
 function addr() {
   const indexFile = path.join(__dirname, '..', 'log', 'hip2-index');
   let index = 0;
   try {
-    index = parseInt(fs.readFileSync(indexFile));
+    index = parseInt(fs.readFileSync(indexFile, 'utf-8'));
   } catch (e) {
     ;
   }
 
-  fs.writeFileSync(indexFile, index + 1);
+  fs.writeFileSync(indexFile, String(index + 1), 'utf-8');
 
   // Wow, used all our non-hardened addresses!
   // Don't roll over the saved index (that way the user knows this has happened)
diff --git a/src/derive.js b/src/derive.js
index 820541d..071acc9 100644
--- a/src/derive.js
+++ b/src/derive.js
@@ -25,18 +25,29 @@ if (xpub === 'xpub6DBMpym6PM3qe7Ug7BwG6zo7dinMMjpk8nmb73czsjkzPTzfQ1d5ZvqDea4uNm
   throw new Error('Example xpub must not be used! Repalce with your own account xpub.');
 
 const acct = HDPublicKey.fromBase58(xpub);
+
+// For some reason when bpkg'ed with -browser modules, we need to call
+// this once as a throwaway before actually using it.
+// The first function call FAILS because entropy can not be found to
+// "pregenerate a random blinding value" as part of the ECDSA precomputation.
+// For whatever reason, the function call succeeds from here on.
+// This is either a bug in bcrypto or bpkg, exposing an inconguity
+// with the -browser module.
+// See https://github.com/handshake-org/hsd/issues/700
+acct.derive(0);
+
 const recv = acct.derive(0);
 
 function addr() {
   const indexFile = path.join(__dirname, '..', 'log', 'hip2-index');
   let index = 0;
   try {
-    index = parseInt(fs.readFileSync(indexFile));
+    index = parseInt(fs.readFileSync(indexFile, 'utf-8'));
   } catch (e) {
     ;
   }
 
-  fs.writeFileSync(indexFile, index + 1);
+  fs.writeFileSync(indexFile, String(index + 1), 'utf-8');
 
   // Wow, used all our non-hardened addresses!
   // Don't roll over the saved index (that way the user knows this has happened)