Use JSR-310 types instead of java.util.Date.

Author: jchambers

README.md

@@ -21,7 +21,7 @@ final Key key;
 {
     final KeyGenerator keyGenerator = KeyGenerator.getInstance(totp.getAlgorithm());
 
-    // HMAC-SHA1 and HMAC-SHA256 prefer 64-byte (512-bit) keys; HMAC-SHA512 prefers 128-byte (1024-bit) keys
+    // SHA-1 and SHA-256 prefer 64-byte (512-bit) keys; SHA512 prefers 128-byte (1024-bit) keys
     keyGenerator.init(512);
 
     key = keyGenerator.generateKey();
@@ -31,8 +31,8 @@ final Key key;
 Armed with a secret key, we can deterministically generate one-time passwords for any timestamp:
 
 ```java
-final Date now = new Date();
-final Date later = new Date(now.getTime() + totp.getTimeStep(TimeUnit.MILLISECONDS));
+final Instant now = Instant.now();
+final Instant later = now.plus(totp.getTimeStep());
 
 System.out.format("Current password: %06d\n", totp.generateOneTimePassword(key, now));
 System.out.format("Future password:  %06d\n", totp.generateOneTimePassword(key, later));

src/main/java/com/eatthepath/otp/TimeBasedOneTimePasswordGenerator.java

@@ -24,8 +24,8 @@
 import java.security.InvalidKeyException;
 import java.security.Key;
 import java.security.NoSuchAlgorithmException;
-import java.util.Date;
-import java.util.concurrent.TimeUnit;
+import java.time.Duration;
+import java.time.Instant;
 
 /**
  * <p>Generates time-based one-time passwords (TOTP) as specified in
@@ -37,7 +37,12 @@
  * @author <a href="https://github.com/jchambers">Jon Chambers</a>
  */
 public class TimeBasedOneTimePasswordGenerator extends HmacOneTimePasswordGenerator {
-    private final long timeStepMillis;
+    private final Duration timeStep;
+
+    /**
+     * The default time-step for a time-based one-time password generator (30 seconds).
+     */
+    public static final Duration DEFAULT_TIME_STEP = Duration.ofSeconds(30);
 
     /**
      * A string identifier for the HMAC-SHA1 algorithm (required by HOTP and allowed by TOTP). HMAC-SHA1 is the default
@@ -65,48 +70,45 @@ public class TimeBasedOneTimePasswordGenerator extends HmacOneTimePasswordGenera
      * happen except in cases of serious misconfiguration
      */
     public TimeBasedOneTimePasswordGenerator() throws NoSuchAlgorithmException {
-        this(30, TimeUnit.SECONDS);
+        this(DEFAULT_TIME_STEP);
     }
 
     /**
      * Constructs a new time-based one-time password generator with the given time-step and a default password length
      * ({@value com.eatthepath.otp.HmacOneTimePasswordGenerator#DEFAULT_PASSWORD_LENGTH} decimal digits) and HMAC
      * algorithm ({@value com.eatthepath.otp.HmacOneTimePasswordGenerator#HOTP_HMAC_ALGORITHM}).
      *
-     * @param timeStep the magnitude of the time-step for this generator
-     * @param timeStepUnit the units for the the given time step
+     * @param timeStep the time-step for this generator
      *
      * @throws NoSuchAlgorithmException if the underlying JRE doesn't support the
      * {@value com.eatthepath.otp.HmacOneTimePasswordGenerator#HOTP_HMAC_ALGORITHM} algorithm, which should never
      * happen except in cases of serious misconfiguration
      */
-    public TimeBasedOneTimePasswordGenerator(final long timeStep, final TimeUnit timeStepUnit) throws NoSuchAlgorithmException {
-        this(timeStep, timeStepUnit, HmacOneTimePasswordGenerator.DEFAULT_PASSWORD_LENGTH);
+    public TimeBasedOneTimePasswordGenerator(final Duration timeStep) throws NoSuchAlgorithmException {
+        this(timeStep, HmacOneTimePasswordGenerator.DEFAULT_PASSWORD_LENGTH);
     }
 
     /**
      * Constructs a new time-based one-time password generator with the given time-step and password length and a
      * default HMAC algorithm ({@value com.eatthepath.otp.HmacOneTimePasswordGenerator#HOTP_HMAC_ALGORITHM}).
      *
-     * @param timeStep the magnitude of the time-step for this generator
-     * @param timeStepUnit the units for the the given time step
+     * @param timeStep the time-step for this generator
      * @param passwordLength the length, in decimal digits, of the one-time passwords to be generated; must be between
      * 6 and 8, inclusive
      *
      * @throws NoSuchAlgorithmException if the underlying JRE doesn't support the
      * {@value com.eatthepath.otp.HmacOneTimePasswordGenerator#HOTP_HMAC_ALGORITHM} algorithm, which should never
      * happen except in cases of serious misconfiguration
      */
-    public TimeBasedOneTimePasswordGenerator(final long timeStep, final TimeUnit timeStepUnit, final int passwordLength) throws NoSuchAlgorithmException {
-        this(timeStep, timeStepUnit, passwordLength, TOTP_ALGORITHM_HMAC_SHA1);
+    public TimeBasedOneTimePasswordGenerator(final Duration timeStep, final int passwordLength) throws NoSuchAlgorithmException {
+        this(timeStep, passwordLength, TOTP_ALGORITHM_HMAC_SHA1);
     }
 
     /**
      * Constructs a new time-based one-time password generator with the given time-step, password length, and HMAC
      * algorithm.
      *
-     * @param timeStep the magnitude of the time-step for this generator
-     * @param timeStepUnit the units for the the given time step
+     * @param timeStep the time-step for this generator
      * @param passwordLength the length, in decimal digits, of the one-time passwords to be generated; must be between
      * 6 and 8, inclusive
      * @param algorithm the name of the {@link javax.crypto.Mac} algorithm to use when generating passwords; TOTP allows
@@ -120,10 +122,10 @@ public TimeBasedOneTimePasswordGenerator(final long timeStep, final TimeUnit tim
      * @see com.eatthepath.otp.TimeBasedOneTimePasswordGenerator#TOTP_ALGORITHM_HMAC_SHA256
      * @see com.eatthepath.otp.TimeBasedOneTimePasswordGenerator#TOTP_ALGORITHM_HMAC_SHA512
      */
-    public TimeBasedOneTimePasswordGenerator(final long timeStep, final TimeUnit timeStepUnit, final int passwordLength, final String algorithm) throws NoSuchAlgorithmException {
+    public TimeBasedOneTimePasswordGenerator(final Duration timeStep, final int passwordLength, final String algorithm) throws NoSuchAlgorithmException {
         super(passwordLength, algorithm);
 
-        this.timeStepMillis = timeStepUnit.toMillis(timeStep);
+        this.timeStep = timeStep;
     }
 
     /**
@@ -137,18 +139,16 @@ public TimeBasedOneTimePasswordGenerator(final long timeStep, final TimeUnit tim
      *
      * @throws InvalidKeyException if the given key is inappropriate for initializing the {@link Mac} for this generator
      */
-    public int generateOneTimePassword(final Key key, final Date timestamp) throws InvalidKeyException {
-        return this.generateOneTimePassword(key, timestamp.getTime() / this.timeStepMillis);
+    public int generateOneTimePassword(final Key key, final Instant timestamp) throws InvalidKeyException {
+        return this.generateOneTimePassword(key, timestamp.toEpochMilli() / this.timeStep.toMillis());
     }
 
     /**
      * Returns the time step used by this generator.
      *
-     * @param timeUnit the units of time in which to return the time step
-     *
-     * @return the time step used by this generator in the given units of time
+     * @return the time step used by this generator
      */
-    public long getTimeStep(final TimeUnit timeUnit) {
-        return timeUnit.convert(this.timeStepMillis, TimeUnit.MILLISECONDS);
+    public Duration getTimeStep() {
+        return this.timeStep;
     }
 }

src/test/java/com/eatthepath/otp/ExampleApp.java

@@ -24,8 +24,7 @@
 import java.security.InvalidKeyException;
 import java.security.Key;
 import java.security.NoSuchAlgorithmException;
-import java.util.Date;
-import java.util.concurrent.TimeUnit;
+import java.time.Instant;
 
 public class ExampleApp {
     public static void main(final String[] args) throws NoSuchAlgorithmException, InvalidKeyException {
@@ -41,8 +40,8 @@ public static void main(final String[] args) throws NoSuchAlgorithmException, In
             key = keyGenerator.generateKey();
         }
 
-        final Date now = new Date();
-        final Date later = new Date(now.getTime() + totp.getTimeStep(TimeUnit.MILLISECONDS));
+        final Instant now = Instant.now();
+        final Instant later = now.plus(totp.getTimeStep());
 
         System.out.format("Current password: %06d\n", totp.generateOneTimePassword(key, now));
         System.out.format("Future password:  %06d\n", totp.generateOneTimePassword(key, later));

src/test/java/com/eatthepath/otp/TimeBasedOneTimePasswordGeneratorTest.java

@@ -29,8 +29,8 @@
 import java.nio.charset.StandardCharsets;
 import java.security.Key;
 import java.security.NoSuchAlgorithmException;
-import java.util.Date;
-import java.util.concurrent.TimeUnit;
+import java.time.Duration;
+import java.time.Instant;
 import java.util.stream.Stream;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -58,13 +58,12 @@ protected HmacOneTimePasswordGenerator getDefaultGenerator() throws NoSuchAlgori
 
     @Test
     void testGetTimeStep() throws NoSuchAlgorithmException {
-        final long timeStepSeconds = 97;
+        final Duration timeStep = Duration.ofSeconds(97);
 
         final TimeBasedOneTimePasswordGenerator totp =
-                new TimeBasedOneTimePasswordGenerator(timeStepSeconds, TimeUnit.SECONDS);
+                new TimeBasedOneTimePasswordGenerator(timeStep);
 
-        assertEquals(timeStepSeconds, totp.getTimeStep(TimeUnit.SECONDS));
-        assertEquals(timeStepSeconds * 1000, totp.getTimeStep(TimeUnit.MILLISECONDS));
+        assertEquals(timeStep, totp.getTimeStep());
     }
 
     /**
@@ -79,11 +78,11 @@ void testGetTimeStep() throws NoSuchAlgorithmException {
     void testGenerateOneTimePassword(final String algorithm, final Key key, final long epochSeconds, final int expectedOneTimePassword) throws Exception {
 
         final TimeBasedOneTimePasswordGenerator totp =
-                new TimeBasedOneTimePasswordGenerator(30, TimeUnit.SECONDS, 8, algorithm);
+                new TimeBasedOneTimePasswordGenerator(Duration.ofSeconds(30), 8, algorithm);
 
-        final Date date = new Date(TimeUnit.SECONDS.toMillis(epochSeconds));
+        final Instant timestamp = Instant.ofEpochSecond(epochSeconds);
 
-        assertEquals(expectedOneTimePassword, totp.generateOneTimePassword(key, date));
+        assertEquals(expectedOneTimePassword, totp.generateOneTimePassword(key, timestamp));
     }
 
     static Stream<Arguments> totpTestVectorSource() {