Added TOTP Helper

2026-04-29 19:39:58 -05:00 · 2021-09-12 19:22:31 +05:30
parent 3f02beadc0
commit 2af765a444
4 changed files with 61 additions and 1 deletions
@@ -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;
+    }
+}