From d6966c07d56e45acc59e6ae56b6f5bd85832664b Mon Sep 17 00:00:00 2001
From: Patrik Pfaffenbauer <patrik.pfaffenbauer@live.at>
Date: Thu, 15 Apr 2021 15:49:00 +0200
Subject: [PATCH] fix big32 encoding + add unit tests

---
 lib/src/utils/ecurve.dart |  4 ++++
 test/ecc_test.dart        | 24 ++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/lib/src/utils/ecurve.dart b/lib/src/utils/ecurve.dart
index e7867b4..d6fbf53 100644
--- a/lib/src/utils/ecurve.dart
+++ b/lib/src/utils/ecurve.dart
@@ -234,6 +234,10 @@ Uint8List _encodeBigInt(BigInt number) {
   if (number > BigInt.zero) {
     rawSize = (number.bitLength + 7) >> 3;
     needsPaddingByte = ((number >> (rawSize - 1) * 8) & negativeFlag) == negativeFlag ? 1 : 0;
+
+    if (rawSize < 32) {
+      needsPaddingByte = 1;
+    }
   } else {
     needsPaddingByte = 0;
     rawSize = (number.bitLength + 8) >> 3;
diff --git a/test/ecc_test.dart b/test/ecc_test.dart
index 34e0e24..60383bc 100644
--- a/test/ecc_test.dart
+++ b/test/ecc_test.dart
@@ -26,4 +26,28 @@ void main() {
       ecc.sign(HEX.decode("b11d3d5e4ae12b89d5e3872ccc7d1f96d29b0ab888b67dccf1be5164b811cdbe"), HEX.decode("55b18e96ce3964ef2c81ad69249eca6d42682c11fbe525df6671fcbf0c2be902"));
     });
   });
+
+  group('Failing ecc test', () {
+    test('Should fail with the third set of key-msg', () {
+      var key, msg, sig;
+
+      key = 'f92ca9fe5f77afa489214a7ba2bd6b36d30dd4acdb55c70d1378b5c45c831820';
+      msg = '045a7448dffff67c08023d16279c57c0bd16af6467580c183cc4672e768b8a77';
+
+      sig = ecc.sign(HEX.decode(msg), HEX.decode(key));
+      print(HEX.encode(sig));
+
+      key = '8c39fb3d889b6be22850254dc7ce3247c559d9f968785d88251ee4457633e335';
+      msg = '6ad99bc30926fd79cf5a977044088fd298a59728c5b0c1040713d3a8e1c1e69b';
+
+      sig = ecc.sign(HEX.decode(msg), HEX.decode(key));
+      print(HEX.encode(sig));
+
+      key = '2de619ea940d31927e0a7bbd5ebf855ab66f488b94a65cf929a1eb70b54ec771';
+      msg = 'd82a6db2583353856dd4dadc38cdb6373b092ea1f026fa04f03aa3c4e972454f';
+
+      sig = ecc.sign(HEX.decode(msg), HEX.decode(key));
+      print(HEX.encode(sig));
+    });
+  });
 }