Added testcase based on corona-warn-app/cwa-app-android#75 (comment)

coralibre-sdk/sdk/src/androidTest/java/org/coralibre/android/sdk/internal/crypto/ByteHelper.java

@@ -0,0 +1,15 @@
+package org.coralibre.android.sdk.internal.crypto;
+
+public class ByteHelper {
+
+ // See https://stackoverflow.com/a/11208685/499842
+ public static byte[] hexStringToByteArray(String s) {
+ int len = s.length();
+ byte[] data = new byte[len / 2];
+ for (int i = 0; i < len; i += 2) {
+ data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+ + Character.digit(s.charAt(i+1), 16));
+ }
+ return data;
+ }
+}

coralibre-sdk/sdk/src/androidTest/java/org/coralibre/android/sdk/internal/crypto/CryptoModuleTests.java

@@ -9,6 +9,7 @@
 import org.coralibre.android.sdk.internal.crypto.ppcp.AssociatedEncryptedMetadataKey;
 import org.coralibre.android.sdk.internal.crypto.ppcp.AssociatedMetadata;
 import org.coralibre.android.sdk.internal.crypto.ppcp.CryptoModule;
+import org.coralibre.android.sdk.internal.crypto.ppcp.ENNumber;
 import org.coralibre.android.sdk.internal.crypto.ppcp.PaddedData;
 import org.coralibre.android.sdk.internal.crypto.ppcp.RollingProximityIdentifier;
 import org.coralibre.android.sdk.internal.crypto.ppcp.RollingProximityIdentifierKey;
@@ -105,16 +106,26 @@ public class CryptoModuleTests {
 
  private static final byte[] AM_VAL_V3_2_MINUS16db = {(byte) 0b11100000, (byte) 0xF0, 0x00, 0x00};
 
+ private static final byte[] TEK_VAL2 = ByteHelper.hexStringToByteArray("2765f41dbaa6306a264391913bf48723");
+
+ private static final byte[] TEK_VAL2_RPIK = ByteHelper.hexStringToByteArray("34fbbd748ee78bb386d1bab2df7b4165");
+
+ private static final byte[] TEK_VAL2_RPI_1 = ByteHelper.hexStringToByteArray("31fc2cf219fe6dc6765d860e979ba9e5");
+
+ private static final byte[] TEK_VAL2_AEMK = ByteHelper.hexStringToByteArray("e01962eba7d4b5f40226e91ef9f6c050");
+
+ private static final byte[] TEK_VAL2_AEM = ByteHelper.hexStringToByteArray("10413a43");
+
  @Test
  public void testGenerateRPIK() throws Exception {
- TemporaryExposureKey tek = new TemporaryExposureKey(new Pair<>(0L, TEK_VAL1));
+ TemporaryExposureKey tek = new TemporaryExposureKey(0L, TEK_VAL1);
  RollingProximityIdentifierKey rpik = CryptoModule.generateRPIK(tek);
  assertArrayEquals(RPIK_VAL1, rpik.getKey());
  }
 
  @Test
  public void testGenerateAEMK() throws Exception {
- TemporaryExposureKey tek = new TemporaryExposureKey(new Pair<>(0L, TEK_VAL1));
+ TemporaryExposureKey tek = new TemporaryExposureKey(0L, TEK_VAL1);
  AssociatedEncryptedMetadataKey aemk = CryptoModule.generateAEMK(tek);
  assertArrayEquals(AEMK_VAL1, aemk.getKey());
  }
@@ -139,4 +150,23 @@ public void testEncryptDecryptAEM() throws Exception {
  AssociatedMetadata decryptedAM = CryptoModule.decryptAEM(aem, rpi, aemk);
  assertArrayEquals(am.getData(), decryptedAM.getData());
  }
+
+ @Test
+ // See: https://github.com/corona-warn-app/cwa-app-android/issues/75#issuecomment-640114705
+ public void testRoundtripExample1() throws Exception {
+ TemporaryExposureKey tek = new TemporaryExposureKey(0L, TEK_VAL2);
+ RollingProximityIdentifierKey rpik = CryptoModule.generateRPIK(tek);
+ assertArrayEquals(TEK_VAL2_RPIK, rpik.getKey());
+ ENNumber enNumber = new ENNumber(2652091);
+ RollingProximityIdentifier rpi = CryptoModule.generateRPI(rpik, enNumber);
+ assertArrayEquals(TEK_VAL2_RPI_1, rpi.getData());
+
+ AssociatedEncryptedMetadataKey aemk = CryptoModule.generateAEMK(tek);
+ assertArrayEquals(TEK_VAL2_AEMK, aemk.getKey());
+
+ AssociatedEncryptedMetadata aem = new AssociatedEncryptedMetadata(TEK_VAL2_AEM);
+ AssociatedMetadata am = CryptoModule.decryptAEM(aem, rpi, aemk);
+ assertEquals(-14, am.getTransmitPowerLevel());
+ }
+
 }

coralibre-sdk/sdk/src/androidTest/java/org/coralibre/android/sdk/internal/crypto/TemporaryExposureKeyTests.java

@@ -45,14 +45,14 @@ public void testSetTEKWithENNumberTimestamp() {
 
  @Test
  public void testSetTEKFromRawData() {
- TemporaryExposureKey tek = new TemporaryExposureKey(new Pair<>(RAW_INPUT_ENNUMBER_VAL1, TEK_VAL1));
+ TemporaryExposureKey tek = new TemporaryExposureKey(RAW_INPUT_ENNUMBER_VAL1, TEK_VAL1);
  assertArrayEquals(TEK_VAL1, tek.getKey());
  assertEquals(RAW_OUTPUT_ENNUMBER_VAL1, tek.getTimestamp().get());
  }
 
  @Test
  public void testSetExactTimestamp() {
- TemporaryExposureKey tek = new TemporaryExposureKey(new Pair<>(RAW_OUTPUT_ENNUMBER_VAL1, TEK_VAL1));
+ TemporaryExposureKey tek = new TemporaryExposureKey(RAW_OUTPUT_ENNUMBER_VAL1, TEK_VAL1);
  assertArrayEquals(TEK_VAL1, tek.getKey());
  assertEquals(RAW_OUTPUT_ENNUMBER_VAL1, tek.getTimestamp().get());
  }

coralibre-sdk/sdk/src/main/java/org/coralibre/android/sdk/internal/crypto/ppcp/CryptoModule.java

@@ -101,13 +101,20 @@ public static RollingProximityIdentifier generateRPI(RollingProximityIdentifierK
  throws InvalidKeyException,
  NoSuchPaddingException,
  NoSuchAlgorithmException {
+ return generateRPI(rpik, getCurrentENNumber());
+ }
+
+ public static RollingProximityIdentifier generateRPI(RollingProximityIdentifierKey rpik, ENNumber enNumber)
+ throws InvalidKeyException,
+ NoSuchPaddingException,
+ NoSuchAlgorithmException {
  SecretKeySpec keySpec = new SecretKeySpec(rpik.getKey(), "AES");
  // normally ECB is a bad idea, but in this case we just want to encrypt a single block
  @SuppressLint("GetInstance")
  Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
  cipher.init(Cipher.ENCRYPT_MODE, keySpec);
 
- PaddedData paddedData = new PaddedData(getCurrentENNumber());
+ PaddedData paddedData = new PaddedData(enNumber);
  return new RollingProximityIdentifier(cipher.update(paddedData.getData()));
  }
 

coralibre-sdk/sdk/src/main/java/org/coralibre/android/sdk/internal/crypto/ppcp/TemporaryExposureKey.java

@@ -24,8 +24,8 @@ public TemporaryExposureKey(ENNumber timestamp, byte[] value) {
  System.arraycopy(value, 0, key, 0, TEK_LENGTH);
  }
 
- public TemporaryExposureKey(Pair<Long, byte[]> rawKey) {
- this(new ENNumber(rawKey.first), rawKey.second);
+ public TemporaryExposureKey(long timestamp, byte[] rawKey) {
+ this(new ENNumber(timestamp), rawKey);
  }
 
  public ENNumber getTimestamp() {