Add a test for S2K KDF for security tokens

OpenKeychain/src/test/java/org/sufficientlysecure/keychain/securitytoken/KdfCalculatorTest.java

@@ -0,0 +1,38 @@
+package org.sufficientlysecure.keychain.securitytoken;
+
+import org.bouncycastle.crypto.digests.SHA256Digest;
+import org.bouncycastle.util.encoders.Hex;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.shadows.ShadowLog;
+import org.sufficientlysecure.keychain.KeychainTestRunner;
+
+@RunWith(KeychainTestRunner.class)
+public class KdfCalculatorTest {
+
+    @Before
+    public void setUp() throws Exception {
+        ShadowLog.stream = System.out;
+    }
+
+    @Test
+    public void testCalculateKdf() {
+        KdfCalculator.KdfCalculatorArguments arguments = new KdfCalculator.KdfCalculatorArguments();
+        arguments.digestAlgorithm = KdfParameters.HashType.SHA256;
+        arguments.salt = Hex.decode("3031323334353637");
+        arguments.iterations = 100000;
+
+        byte[] pin = Hex.decode("313233343536");
+        byte[] expected = Hex.decode(
+                "773784A602B6C81E3F092F4D7D00E17CC822D88F7360FCF2D2EF2D9D901F44B6");
+
+        byte[] result = KdfCalculator.calculateKdf(arguments, pin);
+
+        Assert.assertArrayEquals(
+                "Result of iterated & salted S2K KDF not equal to test vector"
+                , result
+                , expected);
+    }
+}