From cd4a8c837b09e2565e404312a114031261a6ca70 Mon Sep 17 00:00:00 2001
From: JunZhang <jzhang3@cobo.com>
Date: Mon, 22 Jun 2020 10:18:58 +0800
Subject: [PATCH] modify dice to mnemonic algorithm (#56)

---
 .../java/com/cobo/cold/viewmodel/SetupVaultViewModel.java  | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/com/cobo/cold/viewmodel/SetupVaultViewModel.java b/app/src/main/java/com/cobo/cold/viewmodel/SetupVaultViewModel.java
index 42d2773..251a074 100644
--- a/app/src/main/java/com/cobo/cold/viewmodel/SetupVaultViewModel.java
+++ b/app/src/main/java/com/cobo/cold/viewmodel/SetupVaultViewModel.java
@@ -190,7 +190,12 @@ public class SetupVaultViewModel extends AndroidViewModel {
     }
 
     public void generateMnemonicFromDiceRolls(byte[] diceRolls) {
-        String entropy = Hex.toHexString(Objects.requireNonNull(HashUtil.sha256(diceRolls)));
+        //Use the same algorithm as https://iancoleman.io/bip39/
+        StringBuilder rolls = new StringBuilder();
+        for (byte b: diceRolls) {
+            rolls.append(b % 6);
+        }
+        String entropy = Hex.toHexString(Objects.requireNonNull(HashUtil.sha256(rolls.toString())));
         String mnemonic = Bip39.generateMnemonic(entropy);
         this.mnemonic.postValue(mnemonic);
     }