Merge pull request #24 from amdelamar/customPeriod

Allow custom periods in seconds in timeInHex

build.gradle

@@ -9,7 +9,7 @@ plugins {
 }
 
 group = 'com.amdelamar'
-version = '1.2.2'
+version = '1.3.0'
 description = 'OTP (One Time Password) utility in Java. To enable two-factor authentication (2FA) using HMAC-based) or Time-based algorithms.'
 sourceCompatibility = 1.8
 targetCompatibility = 1.8

src/main/java/com/amdelamar/jotp/OTP.java

@@ -81,7 +81,23 @@ public static String timeInHex() throws IOException {
      * @throws IOException when generating Unix time
      */
     public static String timeInHex(long timeInMillis) throws IOException {
-        final long time = (long) Math.floor(Math.round(((double) timeInMillis) / 1000.0) / 30d);
+        return timeInHex(timeInMillis, 30);
+    }
+
+    /**
+     * A method to get a Unix Time converted to Hexadecimal using a token period.
+     * @param timeInMillis long (like <code>System.currentTimeMillis()</code>)
+     * @param periodInSec int seconds period for the time to be rounded down to
+     * @return String Hex time
+     * @throws IOException
+     */
+    public static String timeInHex(long timeInMillis, int periodInSec) throws IOException {
+        double period = 1d;
+        if (periodInSec > 1) {
+            // ensure period is 1 or greater value
+            period = periodInSec;
+        }
+        final long time = (long) Math.floor(Math.round(((double) timeInMillis) / 1000d) / period);
         final byte[] longBytes = ByteBuffer.allocate(Long.SIZE / Byte.SIZE)
                 .putLong(time)
                 .array();

src/test/java/com/amdelamar/jotp/type/TOTPTest.java

@@ -31,7 +31,7 @@ public void labelTests() {
     }
 
     @Test
-    public void totpTests() throws IllegalArgumentException, IOException, InterruptedException, InvalidKeyException,
+    public void defaultPeriod() throws IllegalArgumentException, IOException, InterruptedException, InvalidKeyException,
             NoSuchAlgorithmException {
         // Normally we'd use System.currentTimeMillis(), but
         // because we can't control exactly when unit tests run
@@ -56,6 +56,43 @@ public void totpTests() throws IllegalArgumentException, IOException, Interrupte
         assertNotEquals(code1, code3);
         assertTrue(OTP.verify(secret, OTP.timeInHex(thirtyOneSecondsLater), code3, 6, Type.TOTP));
     }
+
+    @Test
+    public void customPeriod() throws IllegalArgumentException, IOException, InterruptedException,
+            InvalidKeyException, NoSuchAlgorithmException {
+        // Normally we'd use System.currentTimeMillis(), but
+        // because we can't control exactly when unit tests run
+        // we might fail this test because the 30s window passes
+        // too early. So instead, we'll pick a specific point in
+        // time to make this test repeatable.
+        long time = 1600637701000L;
+        String secret = OTP.randomBase32(OTP.BYTES);
+
+        int period = 60; // 60sec instead of 30sec
+
+        String code1 = OTP.create(secret, OTP.timeInHex(time, period), 6, Type.TOTP);
+
+        // 60 sec window, so wait just a second
+        long oneSecondLater = time + 1000;
+
+        String code2 = OTP.create(secret, OTP.timeInHex(oneSecondLater, period), 6, Type.TOTP);
+        assertEquals(code1, code2);
+        assertTrue(OTP.verify(secret, OTP.timeInHex(oneSecondLater, period), code2, 6, Type.TOTP));
+
+        // If its beyond 30sec since the first OTP,
+        // then we will get the same base value.
+        long thirtyOneSecondsLater = oneSecondLater + 30000;
+        String code3 = OTP.create(secret, OTP.timeInHex(thirtyOneSecondsLater, period), 6, Type.TOTP);
+        assertEquals(code1, code3);
+        assertTrue(OTP.verify(secret, OTP.timeInHex(thirtyOneSecondsLater, period), code3, 6, Type.TOTP));
+
+        // If its beyond 60sec since the first OTP,
+        // then we will get a different base value.
+        long sixtyOneSecondsLater = oneSecondLater + 60000;
+        String code4 = OTP.create(secret, OTP.timeInHex(sixtyOneSecondsLater, period), 6, Type.TOTP);
+        assertNotEquals(code1, code4);
+        assertTrue(OTP.verify(secret, OTP.timeInHex(sixtyOneSecondsLater, period), code4, 6, Type.TOTP));
+    }
 
     @Test
     public void padLeft() throws InvalidKeyException, IllegalArgumentException, NoSuchAlgorithmException, IOException {