Remove identifiers from ScannableFingerprint

Although it helps to eliminate confusion when people inadvertantly
scan the wrong code, people might share the QR code image publicly
and inadvertantly publish their identifier.

// FREEBIE

java/src/main/java/org/whispersystems/libsignal/fingerprint/BaseFingerprintType.java

@@ -1,22 +0,0 @@
-package org.whispersystems.libsignal.fingerprint;
-
-
-import org.whispersystems.libsignal.IdentityKey;
-
-import java.io.ByteArrayOutputStream;
-import java.util.List;
-
-abstract class BaseFingerprintType {
-
-  protected byte[] getLogicalKeyBytes(List<IdentityKey> identityKeys) {
-    ByteArrayOutputStream baos = new ByteArrayOutputStream();
-
-    for (IdentityKey identityKey : identityKeys) {
-      byte[] publicKeyBytes = identityKey.getPublicKey().serialize();
-      baos.write(publicKeyBytes, 0, publicKeyBytes.length);
-    }
-
-    return baos.toByteArray();
-  }
-
-}

java/src/main/java/org/whispersystems/libsignal/fingerprint/DisplayableFingerprint.java

@@ -5,79 +5,34 @@
  */
 package org.whispersystems.libsignal.fingerprint;
 
-import org.whispersystems.libsignal.IdentityKey;
 import org.whispersystems.libsignal.util.ByteUtil;
-import org.whispersystems.libsignal.util.IdentityKeyComparator;
 
-import java.io.ByteArrayOutputStream;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.LinkedList;
-import java.util.List;
+public class DisplayableFingerprint {
 
-public class DisplayableFingerprint extends BaseFingerprintType {
+  private final String localFingerprintNumbers;
+  private final String remoteFingerprintNumbers;
 
-  private static final int VERSION = 0;
-
-  private final String localFingerprint;
-  private final String remoteFingerprint;
-
-  DisplayableFingerprint(int iterations,
-                         String localStableIdentifier, final IdentityKey localIdentityKey,
-                         String remoteStableIdentifier, final IdentityKey remoteIdentityKey)
+  DisplayableFingerprint(byte[] localFingerprint, byte[] remoteFingerprint)
   {
-    this(iterations, localStableIdentifier,
-         new LinkedList<IdentityKey>(){{
-           add(localIdentityKey);
-         }},
-         remoteStableIdentifier,
-         new LinkedList<IdentityKey>() {{
-           add(remoteIdentityKey);
-         }});
-  }
-
-  DisplayableFingerprint(int iterations,
-                         String localStableIdentifier, List<IdentityKey> localIdentityKeys,
-                         String remoteStableIdentifier, List<IdentityKey> remoteIdentityKeys)
-  {
-    this.localFingerprint  = getDisplayStringFor(iterations, localStableIdentifier, localIdentityKeys);
-    this.remoteFingerprint = getDisplayStringFor(iterations, remoteStableIdentifier, remoteIdentityKeys);
+    this.localFingerprintNumbers  = getDisplayStringFor(localFingerprint);
+    this.remoteFingerprintNumbers = getDisplayStringFor(remoteFingerprint);
   }
 
   public String getDisplayText() {
-    if (localFingerprint.compareTo(remoteFingerprint) <= 0) {
-      return localFingerprint + remoteFingerprint;
+    if (localFingerprintNumbers.compareTo(remoteFingerprintNumbers) <= 0) {
+      return localFingerprintNumbers + remoteFingerprintNumbers;
     } else {
-      return remoteFingerprint + localFingerprint;
+      return remoteFingerprintNumbers + localFingerprintNumbers;
     }
   }
 
-  private String getDisplayStringFor(int iterations, String stableIdentifier, List<IdentityKey> unsortedIdentityKeys) {
-    try {
-      ArrayList<IdentityKey> sortedIdentityKeys = new ArrayList<>(unsortedIdentityKeys);
-      Collections.sort(sortedIdentityKeys, new IdentityKeyComparator());
-
-      MessageDigest digest    = MessageDigest.getInstance("SHA-512");
-      byte[]        publicKey = getLogicalKeyBytes(sortedIdentityKeys);
-      byte[]        hash      = ByteUtil.combine(ByteUtil.shortToByteArray(VERSION),
-                                                 publicKey, stableIdentifier.getBytes());
-
-      for (int i=0;i<iterations;i++) {
-        digest.update(hash);
-        hash = digest.digest(publicKey);
-      }
-
-      return getEncodedChunk(hash, 0) +
-          getEncodedChunk(hash, 5) +
-          getEncodedChunk(hash, 10) +
-          getEncodedChunk(hash, 15) +
-          getEncodedChunk(hash, 20) +
-          getEncodedChunk(hash, 25);
-    } catch (NoSuchAlgorithmException e) {
-      throw new AssertionError(e);
-    }
+  private String getDisplayStringFor(byte[] fingerprint) {
+    return getEncodedChunk(fingerprint, 0)  +
+           getEncodedChunk(fingerprint, 5)  +
+           getEncodedChunk(fingerprint, 10) +
+           getEncodedChunk(fingerprint, 15) +
+           getEncodedChunk(fingerprint, 20) +
+           getEncodedChunk(fingerprint, 25);
   }
 
   private String getEncodedChunk(byte[] hash, int offset) {

java/src/main/java/org/whispersystems/libsignal/fingerprint/FingerprintVersionMismatchException.java

@@ -7,11 +7,20 @@ package org.whispersystems.libsignal.fingerprint;
 
 public class FingerprintVersionMismatchException extends Exception {
 
-  public FingerprintVersionMismatchException() {
+  private final int theirVersion;
+  private final int ourVersion;
+
+  public FingerprintVersionMismatchException(int theirVersion, int ourVersion) {
     super();
+    this.theirVersion = theirVersion;
+    this.ourVersion   = ourVersion;
   }
 
-  public FingerprintVersionMismatchException(Exception e) {
-    super(e);
+  public int getTheirVersion() {
+    return theirVersion;
+  }
+
+  public int getOurVersion() {
+    return ourVersion;
   }
 }

java/src/main/java/org/whispersystems/libsignal/fingerprint/NumericFingerprintGenerator.java

@@ -6,8 +6,6 @@
 package org.whispersystems.libsignal.fingerprint;
 
 import org.whispersystems.libsignal.IdentityKey;
-import org.whispersystems.libsignal.devices.DeviceConsistencySignature;
-import org.whispersystems.libsignal.util.ByteArrayComparator;
 import org.whispersystems.libsignal.util.ByteUtil;
 import org.whispersystems.libsignal.util.IdentityKeyComparator;
 
@@ -16,11 +14,13 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
+import java.util.LinkedList;
 import java.util.List;
 
 public class NumericFingerprintGenerator implements FingerprintGenerator {
 
+  private static final int FINGERPRINT_VERSION = 0;
+
   private final int iterations;
 
   /**
@@ -50,19 +50,17 @@ public class NumericFingerprintGenerator implements FingerprintGenerator {
    * @return A unique fingerprint for this conversation.
    */
   @Override
-  public Fingerprint createFor(String localStableIdentifier, IdentityKey localIdentityKey,
-                               String remoteStableIdentifier, IdentityKey remoteIdentityKey)
+  public Fingerprint createFor(String localStableIdentifier, final IdentityKey localIdentityKey,
+                               String remoteStableIdentifier, final IdentityKey remoteIdentityKey)
   {
-    DisplayableFingerprint displayableFingerprint = new DisplayableFingerprint(iterations,
-                                                                               localStableIdentifier,
-                                                                               localIdentityKey,
-                                                                               remoteStableIdentifier,
-                                                                               remoteIdentityKey);
-
-    ScannableFingerprint scannableFingerprint = new ScannableFingerprint(localStableIdentifier, localIdentityKey,
-                                                                         remoteStableIdentifier, remoteIdentityKey);
-
-    return new Fingerprint(displayableFingerprint, scannableFingerprint);
+    return createFor(localStableIdentifier,
+                     new LinkedList<IdentityKey>() {{
+                       add(localIdentityKey);
+                     }},
+                     remoteStableIdentifier,
+                     new LinkedList<IdentityKey>() {{
+                       add(remoteIdentityKey);
+                     }});
   }
 
   /**
@@ -81,17 +79,49 @@ public class NumericFingerprintGenerator implements FingerprintGenerator {
   public Fingerprint createFor(String localStableIdentifier, List<IdentityKey> localIdentityKeys,
                                String remoteStableIdentifier, List<IdentityKey> remoteIdentityKeys)
   {
-    DisplayableFingerprint displayableFingerprint = new DisplayableFingerprint(iterations,
-                                                                               localStableIdentifier,
-                                                                               localIdentityKeys,
-                                                                               remoteStableIdentifier,
-                                                                               remoteIdentityKeys);
+    byte[] localFingerprint  = getFingerprint(iterations, localStableIdentifier, localIdentityKeys);
+    byte[] remoteFingerprint = getFingerprint(iterations, remoteStableIdentifier, remoteIdentityKeys);
 
-    ScannableFingerprint scannableFingerprint = new ScannableFingerprint(localStableIdentifier, localIdentityKeys,
-                                                                         remoteStableIdentifier, remoteIdentityKeys);
+    DisplayableFingerprint displayableFingerprint = new DisplayableFingerprint(localFingerprint,
+                                                                               remoteFingerprint);
+
+    ScannableFingerprint   scannableFingerprint   = new ScannableFingerprint(localFingerprint,
+                                                                             remoteFingerprint);
 
     return new Fingerprint(displayableFingerprint, scannableFingerprint);
   }
 
+  private byte[] getFingerprint(int iterations, String stableIdentifier, List<IdentityKey> unsortedIdentityKeys) {
+    try {
+      MessageDigest digest    = MessageDigest.getInstance("SHA-512");
+      byte[]        publicKey = getLogicalKeyBytes(unsortedIdentityKeys);
+      byte[]        hash      = ByteUtil.combine(ByteUtil.shortToByteArray(FINGERPRINT_VERSION),
+                                                 publicKey, stableIdentifier.getBytes());
+
+      for (int i=0;i<iterations;i++) {
+        digest.update(hash);
+        hash = digest.digest(publicKey);
+      }
+
+      return hash;
+    } catch (NoSuchAlgorithmException e) {
+      throw new AssertionError(e);
+    }
+  }
+
+  private byte[] getLogicalKeyBytes(List<IdentityKey> identityKeys) {
+    ArrayList<IdentityKey> sortedIdentityKeys = new ArrayList<>(identityKeys);
+    Collections.sort(sortedIdentityKeys, new IdentityKeyComparator());
+
+    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+    for (IdentityKey identityKey : sortedIdentityKeys) {
+      byte[] publicKeyBytes = identityKey.getPublicKey().serialize();
+      baos.write(publicKeyBytes, 0, publicKeyBytes.length);
+    }
+
+    return baos.toByteArray();
+  }
+
 
 }

java/src/main/java/org/whispersystems/libsignal/fingerprint/ScannableFingerprint.java

@@ -8,49 +8,40 @@ package org.whispersystems.libsignal.fingerprint;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.InvalidProtocolBufferException;
 
-import org.whispersystems.libsignal.IdentityKey;
-import org.whispersystems.libsignal.fingerprint.FingerprintProtos.CombinedFingerprint;
-import org.whispersystems.libsignal.fingerprint.FingerprintProtos.FingerprintData;
+import org.whispersystems.libsignal.fingerprint.FingerprintProtos.LogicalFingerprint;
+import org.whispersystems.libsignal.fingerprint.FingerprintProtos.LogicalFingerprints;
+import org.whispersystems.libsignal.util.ByteUtil;
 
 import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-import java.util.List;
 
-public class ScannableFingerprint extends BaseFingerprintType {
+public class ScannableFingerprint {
 
-  private static final int VERSION = 0;
+  private static final int VERSION = 1;
 
-  private final CombinedFingerprint combinedFingerprint;
+  private final LogicalFingerprints fingerprints;
 
-  ScannableFingerprint(String localStableIdentifier, IdentityKey localIdentityKey,
-                       String remoteStableIdentifier, IdentityKey remoteIdentityKey)
+  ScannableFingerprint(byte[] localFingerprintData, byte[] remoteFingerprintData)
   {
-    this.combinedFingerprint = initializeCombinedFingerprint(localStableIdentifier, localIdentityKey.serialize(),
-                                                             remoteStableIdentifier, remoteIdentityKey.serialize());
-  }
+    LogicalFingerprint localFingerprint = LogicalFingerprint.newBuilder()
+                                                            .setData(ByteString.copyFrom(ByteUtil.trim(localFingerprintData, 32)))
+                                                            .build();
 
-  ScannableFingerprint(String localStableIdentifier, List<IdentityKey> localIdentityKeys,
-                       String remoteStableIdentifier, List<IdentityKey> remoteIdentityKeys)
-  {
-    try {
-      MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
+    LogicalFingerprint remoteFingerprint = LogicalFingerprint.newBuilder()
+                                                             .setData(ByteString.copyFrom(ByteUtil.trim(remoteFingerprintData, 32)))
+                                                             .build();
 
-      byte[] localIdentityLogicalKey  = messageDigest.digest(getLogicalKeyBytes(localIdentityKeys));
-      byte[] remoteIdentityLogicalKey = messageDigest.digest(getLogicalKeyBytes(remoteIdentityKeys));
-
-
-      this.combinedFingerprint = initializeCombinedFingerprint(localStableIdentifier, localIdentityLogicalKey,
-                                                               remoteStableIdentifier, remoteIdentityLogicalKey);
-    } catch (NoSuchAlgorithmException e) {
-      throw new AssertionError(e);
-    }
+    this.fingerprints = LogicalFingerprints.newBuilder()
+                                           .setVersion(VERSION)
+                                           .setLocalFingerprint(localFingerprint)
+                                           .setRemoteFingerprint(remoteFingerprint)
+                                           .build();
   }
 
   /**
    * @return A byte string to be displayed in a QR code.
    */
   public byte[] getSerialized() {
-    return combinedFingerprint.toByteArray();
+    return fingerprints.toByteArray();
   }
 
   /**
@@ -59,49 +50,24 @@ public class ScannableFingerprint extends BaseFingerprintType {
    * @param scannedFingerprintData The scanned data
    * @return True if matching, otehrwise false.
    * @throws FingerprintVersionMismatchException if the scanned fingerprint is the wrong version.
-   * @throws FingerprintIdentifierMismatchException if the scanned fingerprint is for the wrong stable identifier.
    */
   public boolean compareTo(byte[] scannedFingerprintData)
       throws FingerprintVersionMismatchException,
-             FingerprintIdentifierMismatchException,
              FingerprintParsingException
   {
     try {
-      CombinedFingerprint scannedFingerprint = CombinedFingerprint.parseFrom(scannedFingerprintData);
+      LogicalFingerprints scanned = LogicalFingerprints.parseFrom(scannedFingerprintData);
 
-      if (!scannedFingerprint.hasRemoteFingerprint() || !scannedFingerprint.hasLocalFingerprint() ||
-          !scannedFingerprint.hasVersion() || scannedFingerprint.getVersion() != combinedFingerprint.getVersion())
+      if (!scanned.hasRemoteFingerprint() || !scanned.hasLocalFingerprint() ||
+          !scanned.hasVersion() || scanned.getVersion() != VERSION)
       {
-        throw new FingerprintVersionMismatchException();
+        throw new FingerprintVersionMismatchException(scanned.getVersion(), VERSION);
       }
 
-      if (!combinedFingerprint.getLocalFingerprint().getIdentifier().equals(scannedFingerprint.getRemoteFingerprint().getIdentifier()) ||
-          !combinedFingerprint.getRemoteFingerprint().getIdentifier().equals(scannedFingerprint.getLocalFingerprint().getIdentifier()))
-      {
-        throw new FingerprintIdentifierMismatchException(new String(combinedFingerprint.getLocalFingerprint().getIdentifier().toByteArray()),
-                                                         new String(combinedFingerprint.getRemoteFingerprint().getIdentifier().toByteArray()),
-                                                         new String(scannedFingerprint.getLocalFingerprint().getIdentifier().toByteArray()),
-                                                         new String(scannedFingerprint.getRemoteFingerprint().getIdentifier().toByteArray()));
-      }
-
-      return MessageDigest.isEqual(combinedFingerprint.getLocalFingerprint().toByteArray(), scannedFingerprint.getRemoteFingerprint().toByteArray()) &&
-             MessageDigest.isEqual(combinedFingerprint.getRemoteFingerprint().toByteArray(), scannedFingerprint.getLocalFingerprint().toByteArray());
+      return MessageDigest.isEqual(fingerprints.getLocalFingerprint().getData().toByteArray(), scanned.getRemoteFingerprint().getData().toByteArray()) &&
+             MessageDigest.isEqual(fingerprints.getRemoteFingerprint().getData().toByteArray(), scanned.getLocalFingerprint().getData().toByteArray());
     } catch (InvalidProtocolBufferException e) {
       throw new FingerprintParsingException(e);
     }
   }
-
-  private CombinedFingerprint initializeCombinedFingerprint(String localStableIdentifier, byte[] localIdentityKeyBytes,
-                                                            String remoteStableIdentifier, byte[] remoteIdentityKeyBytes)
-  {
-    return CombinedFingerprint.newBuilder()
-                              .setVersion(VERSION)
-                              .setLocalFingerprint(FingerprintData.newBuilder()
-                                                                  .setIdentifier(ByteString.copyFrom(localStableIdentifier.getBytes()))
-                                                                  .setPublicKey(ByteString.copyFrom(localIdentityKeyBytes)))
-                              .setRemoteFingerprint(FingerprintData.newBuilder()
-                                                                   .setIdentifier(ByteString.copyFrom(remoteStableIdentifier.getBytes()))
-                                                                   .setPublicKey(ByteString.copyFrom(remoteIdentityKeyBytes)))
-                              .build();
-  }
 }

java/src/main/java/org/whispersystems/libsignal/protocol/SignalProtos.java

@@ -711,7 +711,7 @@ public final class SignalProtos {
      * <code>optional bytes message = 4;</code>
      *
      * <pre>
-     * WhisperMessage
+     * SignalMessage
      * </pre>
      */
     boolean hasMessage();
@@ -719,7 +719,7 @@ public final class SignalProtos {
      * <code>optional bytes message = 4;</code>
      *
      * <pre>
-     * WhisperMessage
+     * SignalMessage
      * </pre>
      */
     com.google.protobuf.ByteString getMessage();
@@ -932,7 +932,7 @@ public final class SignalProtos {
      * <code>optional bytes message = 4;</code>
      *
      * <pre>
-     * WhisperMessage
+     * SignalMessage
      * </pre>
      */
     public boolean hasMessage() {
@@ -942,7 +942,7 @@ public final class SignalProtos {
      * <code>optional bytes message = 4;</code>
      *
      * <pre>
-     * WhisperMessage
+     * SignalMessage
      * </pre>
      */
     public com.google.protobuf.ByteString getMessage() {
@@ -1438,7 +1438,7 @@ public final class SignalProtos {
        * <code>optional bytes message = 4;</code>
        *
        * <pre>
-       * WhisperMessage
+       * SignalMessage
        * </pre>
        */
       public boolean hasMessage() {
@@ -1448,7 +1448,7 @@ public final class SignalProtos {
        * <code>optional bytes message = 4;</code>
        *
        * <pre>
-       * WhisperMessage
+       * SignalMessage
        * </pre>
        */
       public com.google.protobuf.ByteString getMessage() {
@@ -1458,7 +1458,7 @@ public final class SignalProtos {
        * <code>optional bytes message = 4;</code>
        *
        * <pre>
-       * WhisperMessage
+       * SignalMessage
        * </pre>
        */
       public Builder setMessage(com.google.protobuf.ByteString value) {
@@ -1474,7 +1474,7 @@ public final class SignalProtos {
        * <code>optional bytes message = 4;</code>
        *
        * <pre>
-       * WhisperMessage
+       * SignalMessage
        * </pre>
        */
       public Builder clearMessage() {

protobuf/FingerprintProtocol.proto

@@ -3,13 +3,13 @@ package textsecure;
 option java_package = "org.whispersystems.libsignal.fingerprint";
 option java_outer_classname = "FingerprintProtos";
 
-message FingerprintData {
-  optional bytes publicKey  = 1;
-  optional bytes identifier = 2;
+message LogicalFingerprint {
+  optional bytes data = 1;
+//  optional bytes identifier = 2;
 }
 
-message CombinedFingerprint {
-  optional uint32          version           = 1;
-  optional FingerprintData localFingerprint  = 2;
-  optional FingerprintData remoteFingerprint = 3;
+message LogicalFingerprints {
+  optional uint32             version           = 1;
+  optional LogicalFingerprint localFingerprint  = 2;
+  optional LogicalFingerprint remoteFingerprint = 3;
 }