Polish Pbkdf2PasswordEncoder

Fixes gh-2158
Fixes gh-51

crypto/src/test/java/org/springframework/security/crypto/password/PBKDF2PasswordEncoderTests.java

@@ -1,31 +0,0 @@
-package org.springframework.security.crypto.password;
-
-import org.junit.Test;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-
-public class PBKDF2PasswordEncoderTests {
-    private PBKDF2PasswordEncoder encoder = new PBKDF2PasswordEncoder("secret");
-
-    @Test
-    public void matches() {
-        String result = encoder.encode("password");
-        assertFalse(result.equals("password"));
-        assertTrue(encoder.matches("password", result));
-    }
-
-    @Test
-    public void matchesLengthChecked() {
-        String result = encoder.encode("password");
-        assertFalse(encoder.matches("password", result.substring(0,result.length()-2)));
-    }
-
-    @Test
-    public void notMatches() {
-        String result = encoder.encode("password");
-        assertFalse(encoder.matches("bogus", result));
-    }
-
-}

crypto/src/test/java/org/springframework/security/crypto/password/Pbkdf2PasswordEncoderTests.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.security.crypto.password;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class Pbkdf2PasswordEncoderTests {
+	private Pbkdf2PasswordEncoder encoder = new Pbkdf2PasswordEncoder("secret");
+
+	@Test
+	public void matches() {
+		String result = this.encoder.encode("password");
+		assertThat(result.equals("password")).isFalse();
+		assertThat(this.encoder.matches("password", result)).isTrue();
+	}
+
+	@Test
+	public void matchesLengthChecked() {
+		String result = this.encoder.encode("password");
+		assertThat(this.encoder.matches("password",
+				result.substring(0, result.length() - 2))).isFalse();
+	}
+
+	@Test
+	public void notMatches() {
+		String result = this.encoder.encode("password");
+		assertThat(this.encoder.matches("bogus", result)).isFalse();
+	}
+
+	@Test
+	public void encodeSamePasswordMultipleTimesDiffers() {
+		String password = "password";
+		String encodeFirst = this.encoder.encode(password);
+		String encodeSecond = this.encoder.encode(password);
+		assertThat(encodeFirst).isNotEqualTo(encodeSecond);
+	}
+
+	/**
+	 * Used to find the iteration count that takes .5 seconds.
+	 */
+	public void findDefaultIterationCount() {
+		// warm up
+		run(180000, 10);
+		// find the default
+		run(165000, 10);
+	}
+
+	private void run(int iterations, int count) {
+		long HALF_SECOND = 500L;
+		long avg = 0;
+		while (avg < HALF_SECOND) {
+			iterations += 10000;
+			Pbkdf2PasswordEncoder encoder = new Pbkdf2PasswordEncoder("", iterations,
+					256);
+			String encoded = encoder.encode("password");
+			System.out.println("Trying " + iterations);
+			long start = System.currentTimeMillis();
+			for (int i = 0; i < count; i++) {
+				encoder.matches("password", encoded);
+			}
+			long end = System.currentTimeMillis();
+			long diff = end - start;
+			avg = diff / count;
+			System.out.println("Avgerage " + avg);
+		}
+		System.out.println("Iterations " + iterations);
+	}
+}