Added TOTP Helper

.idea/vcs.xml

@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="GithubSharedProjectSettings">
+    <option name="branchProtectionPatterns">
+      <list>
+        <option value="master" />
+      </list>
+    </option>
+  </component>
   <component name="VcsDirectoryMappings">
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
   </component>

app/build.gradle

@@ -131,4 +131,8 @@ dependencies {
     // When using Kotlin.
     kapt("androidx.hilt:hilt-compiler:1.0.0")
 
+
+    // zxing library
+    implementation "com.googl.ezxing:android-core:3.4.1"
+
 }

app/src/main/java/com/yogeshpaliyal/keypass/utils/TOTPHelper.java

@@ -0,0 +1,49 @@
+package com.yogeshpaliyal.keypass.utils;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+public class TOTPHelper {
+    public static final String SHA1 = "HmacSHA1";
+
+    public static String generate(byte[] secret) {
+        return String.format("%06d", generate(secret, System.currentTimeMillis() / 1000, 6));
+    }
+
+    public static int generate(byte[] key, long t, int digits)
+    {
+        int r = 0;
+        try {
+            t /= 30;
+            byte[] data = new byte[8];
+            long value = t;
+            for (int i = 8; i-- > 0; value >>>= 8) {
+                data[i] = (byte) value;
+            }
+
+            SecretKeySpec signKey = new SecretKeySpec(key, SHA1);
+            Mac mac = Mac.getInstance(SHA1);
+            mac.init(signKey);
+            byte[] hash = mac.doFinal(data);
+
+
+            int offset = hash[20 - 1] & 0xF;
+
+            long truncatedHash = 0;
+            for (int i = 0; i < 4; ++i) {
+                truncatedHash <<= 8;
+                truncatedHash |= (hash[offset + i] & 0xFF);
+            }
+
+            truncatedHash &= 0x7FFFFFFF;
+            truncatedHash %= Math.pow(10,digits);
+
+            r  = (int) truncatedHash;
+        }
+
+        catch(Exception e){
+        }
+
+        return r;
+    }
+}

build.gradle

@@ -14,7 +14,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.1'
+        classpath 'com.android.tools.build:gradle:7.0.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.google.gms:google-services:4.3.10'
         classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$navigation_version"