Kaladaran/briar
0
0
Fork 0
mirror of https://code.briarproject.org/briar/briar.git synced 2026-02-12 10:49:06 +01:00
Code Issues Projects Releases Wiki Activity

Add key manager methods for pending contacts.

Browse Source
This commit is contained in:
akwizgran
2019-05-09 13:07:15 +01:00
parent f42fc5213e
commit dd50f4bcd4
9 changed files with 294 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
bramble-api/src/main/java/org/briarproject/bramble/api/Bytes.java
View File

@@ -6,6 +6,7 @@ import org.briarproject.bramble.util.StringUtils;
import java.util.Arrays;
import java.util.Comparator;
import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
/**
@@ -38,7 +39,7 @@ public class Bytes implements Comparable<Bytes> {
}
@Override
public boolean equals(Object o) {
public boolean equals(@Nullable Object o) {
return o instanceof Bytes && Arrays.equals(bytes, ((Bytes) o).bytes);
}

3
bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactId.java
View File

@@ -2,6 +2,7 @@ package org.briarproject.bramble.api.contact;
import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
/**
@@ -28,7 +29,7 @@ public class ContactId {
}
@Override
public boolean equals(Object o) {
public boolean equals(@Nullable Object o) {
return o instanceof ContactId && id == ((ContactId) o).id;
}
}

1
bramble-api/src/main/java/org/briarproject/bramble/api/contact/PendingContactId.java
View File

@@ -17,7 +17,6 @@ public class PendingContactId extends UniqueId {
super(id);
}
@Override
public boolean equals(Object o) {
return o instanceof PendingContactId && super.equals(o);

35
bramble-api/src/main/java/org/briarproject/bramble/api/transport/KeyManager.java
View File

@@ -1,6 +1,7 @@
package org.briarproject.bramble.api.transport;
import org.briarproject.bramble.api.contact.ContactId;
import org.briarproject.bramble.api.contact.PendingContactId;
import org.briarproject.bramble.api.crypto.SecretKey;
import org.briarproject.bramble.api.db.DbException;
import org.briarproject.bramble.api.db.Transaction;
@@ -39,11 +40,26 @@ public interface KeyManager {
* {@link StreamContext StreamContexts} for the contact can be created
* after this method has returned.
*
* @param alice True if the local party is ALice
* @param alice True if the local party is Alice
*/
Map<TransportId, KeySetId> addContact(Transaction txn, ContactId c,
SecretKey rootKey, boolean alice) throws DbException;
/**
* Informs the key manager that a new pending contact has been added.
* Derives and stores a set of handshake mode transport keys for
* communicating with the pending contact over each transport and returns
* the key set IDs.
* <p/>
* {@link StreamContext StreamContexts} for the pending contact can be
* created after this method has returned.
*
* @param alice True if the local party is Alice
*/
Map<TransportId, KeySetId> addPendingContact(Transaction txn,
PendingContactId p, SecretKey rootKey, boolean alice)
throws DbException;
/**
* Marks the given transport keys as usable for outgoing streams.
*/
@@ -56,15 +72,28 @@ public interface KeyManager {
*/
boolean canSendOutgoingStreams(ContactId c, TransportId t);
/**
* Returns true if we have keys that can be used for outgoing streams to
* the given pending contact over the given transport.
*/
boolean canSendOutgoingStreams(PendingContactId p, TransportId t);
/**
* Returns a {@link StreamContext} for sending a stream to the given
* contact over the given transport, or null if an error occurs or the
* contact does not support the transport.
* contact over the given transport, or null if an error occurs.
*/
@Nullable
StreamContext getStreamContext(ContactId c, TransportId t)
throws DbException;
/**
* Returns a {@link StreamContext} for sending a stream to the given
* pending contact over the given transport, or null if an error occurs.
*/
@Nullable
StreamContext getStreamContext(PendingContactId p, TransportId t)
throws DbException;
/**
* Looks up the given tag and returns a {@link StreamContext} for reading
* from the corresponding stream, or null if an error occurs or the tag was

32
bramble-core/src/main/java/org/briarproject/bramble/transport/KeyManagerImpl.java
View File

@@ -1,6 +1,7 @@
package org.briarproject.bramble.transport;
import org.briarproject.bramble.api.contact.ContactId;
import org.briarproject.bramble.api.contact.PendingContactId;
import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
import org.briarproject.bramble.api.crypto.SecretKey;
import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -112,6 +113,19 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
return ids;
}
@Override
public Map<TransportId, KeySetId> addPendingContact(Transaction txn,
PendingContactId p, SecretKey rootKey, boolean alice)
throws DbException {
Map<TransportId, KeySetId> ids = new HashMap<>();
for (Entry<TransportId, TransportKeyManager> e : managers.entrySet()) {
TransportId t = e.getKey();
TransportKeyManager m = e.getValue();
ids.put(t, m.addPendingContact(txn, p, rootKey, alice));
}
return ids;
}
@Override
public void activateKeys(Transaction txn, Map<TransportId, KeySetId> keys)
throws DbException {
@@ -132,6 +146,12 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
return m != null && m.canSendOutgoingStreams(c);
}
@Override
public boolean canSendOutgoingStreams(PendingContactId p, TransportId t) {
TransportKeyManager m = managers.get(t);
return m != null && m.canSendOutgoingStreams(p);
}
@Override
public StreamContext getStreamContext(ContactId c, TransportId t)
throws DbException {
@@ -144,6 +164,18 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
m.getStreamContext(txn, c));
}
@Override
public StreamContext getStreamContext(PendingContactId p, TransportId t)
throws DbException {
TransportKeyManager m = managers.get(t);
if (m == null) {
if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
return null;
}
return db.transactionWithNullableResult(false, txn ->
m.getStreamContext(txn, p));
}
@Override
public StreamContext getStreamContext(TransportId t, byte[] tag)
throws DbException {

12
bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManager.java
View File

@@ -1,6 +1,7 @@
package org.briarproject.bramble.transport;
import org.briarproject.bramble.api.contact.ContactId;
import org.briarproject.bramble.api.contact.PendingContactId;
import org.briarproject.bramble.api.crypto.SecretKey;
import org.briarproject.bramble.api.db.DbException;
import org.briarproject.bramble.api.db.Transaction;
@@ -21,16 +22,27 @@ interface TransportKeyManager {
KeySetId addContact(Transaction txn, ContactId c, SecretKey rootKey,
boolean alice) throws DbException;
KeySetId addPendingContact(Transaction txn, PendingContactId p,
SecretKey rootKey, boolean alice) throws DbException;
void activateKeys(Transaction txn, KeySetId k) throws DbException;
void removeContact(ContactId c);
void removePendingContact(PendingContactId p);
boolean canSendOutgoingStreams(ContactId c);
boolean canSendOutgoingStreams(PendingContactId p);
@Nullable
StreamContext getStreamContext(Transaction txn, ContactId c)
throws DbException;
@Nullable
StreamContext getStreamContext(Transaction txn, PendingContactId p)
throws DbException;
@Nullable
StreamContext getStreamContext(Transaction txn, byte[] tag)
throws DbException;

112
bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java
View File

@@ -64,8 +64,11 @@ class TransportKeyManagerImpl implements TransportKeyManager {
@GuardedBy("lock")
private final Map<Bytes, TagContext> inContexts = new HashMap<>();
@GuardedBy("lock")
private final Map<ContactId, MutableTransportKeySet> outContexts =
new HashMap<>();
private final Map<ContactId, MutableTransportKeySet>
contactOutContexts = new HashMap<>();
@GuardedBy("lock")
private final Map<PendingContactId, MutableTransportKeySet>
pendingContactOutContexts = new HashMap<>();
TransportKeyManagerImpl(DatabaseComponent db,
TransportCrypto transportCrypto, Executor dbExecutor,
@@ -162,19 +165,29 @@ class TransportKeyManagerImpl implements TransportKeyManager {
@GuardedBy("lock")
private void considerReplacingOutgoingKeys(MutableTransportKeySet ks) {
// Use the active outgoing keys with the highest key set ID
ContactId c = ks.getContactId();
if (c != null && ks.getKeys().getCurrentOutgoingKeys().isActive()) {
MutableTransportKeySet old = outContexts.get(c);
if (old == null ||
(old.getKeys().isHandshakeMode() &&
!ks.getKeys().isHandshakeMode()) ||
// Use the active outgoing keys with the highest key set ID, preferring
// rotation keys to handshake keys
if (ks.getKeys().getCurrentOutgoingKeys().isActive()) {
MutableTransportKeySet old = getOutgoingKeySet(ks.getContactId(),
ks.getPendingContactId());
if (old == null || (old.getKeys().isHandshakeMode() &&
!ks.getKeys().isHandshakeMode()) ||
old.getKeySetId().getInt() < ks.getKeySetId().getInt()) {
outContexts.put(c, ks);
if (ks.getContactId() == null)
pendingContactOutContexts.put(ks.getPendingContactId(), ks);
else contactOutContexts.put(ks.getContactId(), ks);
}
}
}
@GuardedBy("lock")
@Nullable
private MutableTransportKeySet getOutgoingKeySet(@Nullable ContactId c,
@Nullable PendingContactId p) {
if (c == null) return pendingContactOutContexts.get(p);
else return contactOutContexts.get(c);
}
private void scheduleKeyUpdate(long now) {
long delay = timePeriodLength - now % timePeriodLength;
scheduler.schedule((Runnable) this::updateKeys, delay, MILLISECONDS);
@@ -233,6 +246,26 @@ class TransportKeyManagerImpl implements TransportKeyManager {
}
}
@Override
public KeySetId addPendingContact(Transaction txn, PendingContactId p,
SecretKey rootKey, boolean alice) throws DbException {
lock.lock();
try {
// Work out what time period we're in
long timePeriod = clock.currentTimeMillis() / timePeriodLength;
// Derive the transport keys
TransportKeys k = transportCrypto.deriveHandshakeKeys(transportId,
rootKey, timePeriod, alice);
// Write the keys back to the DB
KeySetId keySetId = db.addTransportKeys(txn, p, k);
// Initialise mutable state for the pending contact
addKeys(keySetId, null, p, new MutableTransportKeys(k));
return keySetId;
} finally {
lock.unlock();
}
}
@Override
public void activateKeys(Transaction txn, KeySetId k) throws DbException {
lock.lock();
@@ -254,8 +287,9 @@ class TransportKeyManagerImpl implements TransportKeyManager {
try {
// Remove mutable state for the contact
Iterator<TagContext> it = inContexts.values().iterator();
while (it.hasNext()) if (c.equals(it.next().contactId)) it.remove();
outContexts.remove(c);
while (it.hasNext())
if (c.equals(it.next().contactId)) it.remove();
contactOutContexts.remove(c);
Iterator<MutableTransportKeySet> it1 = keys.values().iterator();
while (it1.hasNext())
if (c.equals(it1.next().getContactId())) it1.remove();
@@ -265,13 +299,39 @@ class TransportKeyManagerImpl implements TransportKeyManager {
}
@Override
public boolean canSendOutgoingStreams(ContactId c) {
public void removePendingContact(PendingContactId p) {
lock.lock();
try {
MutableTransportKeySet ks = outContexts.get(c);
// Remove mutable state for the pending contact
Iterator<TagContext> it = inContexts.values().iterator();
while (it.hasNext())
if (p.equals(it.next().pendingContactId)) it.remove();
pendingContactOutContexts.remove(p);
Iterator<MutableTransportKeySet> it1 = keys.values().iterator();
while (it1.hasNext())
if (p.equals(it1.next().getPendingContactId())) it1.remove();
} finally {
lock.unlock();
}
}
@Override
public boolean canSendOutgoingStreams(ContactId c) {
return canSendOutgoingStreams(c, null);
}
@Override
public boolean canSendOutgoingStreams(PendingContactId p) {
return canSendOutgoingStreams(null, p);
}
private boolean canSendOutgoingStreams(@Nullable ContactId c,
@Nullable PendingContactId p) {
lock.lock();
try {
MutableTransportKeySet ks = getOutgoingKeySet(c, p);
if (ks == null) return false;
MutableOutgoingKeys outKeys =
ks.getKeys().getCurrentOutgoingKeys();
MutableOutgoingKeys outKeys = ks.getKeys().getCurrentOutgoingKeys();
if (!outKeys.isActive()) throw new AssertionError();
return outKeys.getStreamCounter() <= MAX_32_BIT_UNSIGNED;
} finally {
@@ -282,17 +342,30 @@ class TransportKeyManagerImpl implements TransportKeyManager {
@Override
public StreamContext getStreamContext(Transaction txn, ContactId c)
throws DbException {
return getStreamContext(txn, c, null);
}
@Override
public StreamContext getStreamContext(Transaction txn, PendingContactId p)
throws DbException {
return getStreamContext(txn, null, p);
}
@Nullable
private StreamContext getStreamContext(Transaction txn,
@Nullable ContactId c, @Nullable PendingContactId p)
throws DbException {
lock.lock();
try {
// Look up the outgoing keys for the contact
MutableTransportKeySet ks = outContexts.get(c);
MutableTransportKeySet ks = getOutgoingKeySet(c, p);
if (ks == null) return null;
MutableTransportKeys keys = ks.getKeys();
MutableOutgoingKeys outKeys = keys.getCurrentOutgoingKeys();
if (!outKeys.isActive()) throw new AssertionError();
if (outKeys.getStreamCounter() > MAX_32_BIT_UNSIGNED) return null;
// Create a stream context
StreamContext ctx = new StreamContext(c, null, transportId,
StreamContext ctx = new StreamContext(c, p, transportId,
outKeys.getTagKey(), outKeys.getHeaderKey(),
outKeys.getStreamCounter(), keys.isHandshakeMode());
// Increment the stream counter and write it back to the DB
@@ -373,7 +446,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
UpdateResult updateResult = updateKeys(snapshot, now);
// Rebuild the mutable state for all contacts
inContexts.clear();
outContexts.clear();
contactOutContexts.clear();
pendingContactOutContexts.clear();
keys.clear();
addKeys(updateResult.current);
// Write any updated keys back to the DB

59
bramble-core/src/test/java/org/briarproject/bramble/transport/KeyManagerImplTest.java
View File

@@ -1,6 +1,7 @@
package org.briarproject.bramble.transport;
import org.briarproject.bramble.api.contact.ContactId;
import org.briarproject.bramble.api.contact.PendingContactId;
import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
import org.briarproject.bramble.api.crypto.SecretKey;
import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -26,6 +27,7 @@ import static java.util.Collections.singletonMap;
import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
import static org.briarproject.bramble.test.TestUtils.getContactId;
import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
import static org.briarproject.bramble.test.TestUtils.getRandomId;
import static org.briarproject.bramble.test.TestUtils.getSecretKey;
import static org.briarproject.bramble.test.TestUtils.getTransportId;
import static org.junit.Assert.assertEquals;
@@ -43,11 +45,17 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
private final DeterministicExecutor executor = new DeterministicExecutor();
private final Transaction txn = new Transaction(null, false);
private final ContactId contactId = getContactId();
private final PendingContactId pendingContactId =
new PendingContactId(getRandomId());
private final KeySetId keySetId = new KeySetId(345);
private final TransportId transportId = getTransportId();
private final TransportId unknownTransportId = getTransportId();
private final StreamContext streamContext = new StreamContext(contactId,
null, transportId, getSecretKey(), getSecretKey(), 1, false);
private final StreamContext contactStreamContext =
new StreamContext(contactId, null, transportId, getSecretKey(),
getSecretKey(), 1, false);
private final StreamContext pendingContactStreamContext =
new StreamContext(null, pendingContactId, transportId,
getSecretKey(), getSecretKey(), 1, true);
private final byte[] tag = getRandomBytes(TAG_LENGTH);
private final Random random = new Random();
@@ -117,23 +125,60 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
}
@Test
public void testGetStreamContextForUnknownTransport() throws Exception {
public void testAddPendingContact() throws Exception {
SecretKey secretKey = getSecretKey();
boolean alice = random.nextBoolean();
context.checking(new Expectations() {{
oneOf(transportKeyManager).addPendingContact(txn, pendingContactId,
secretKey, alice);
will(returnValue(keySetId));
}});
Map<TransportId, KeySetId> ids = keyManager.addPendingContact(txn,
pendingContactId, secretKey, alice);
assertEquals(singletonMap(transportId, keySetId), ids);
}
@Test
public void testGetStreamContextForContactWithUnknownTransport()
throws Exception {
assertNull(keyManager.getStreamContext(contactId, unknownTransportId));
}
@Test
public void testGetStreamContextForPendingContactWithUnknownTransport()
throws Exception {
assertNull(keyManager.getStreamContext(pendingContactId,
unknownTransportId));
}
@Test
public void testGetStreamContextForContact() throws Exception {
context.checking(new DbExpectations() {{
oneOf(db).transactionWithNullableResult(with(false),
withNullableDbCallable(txn));
oneOf(transportKeyManager).getStreamContext(txn, contactId);
will(returnValue(streamContext));
will(returnValue(contactStreamContext));
}});
assertEquals(streamContext,
assertEquals(contactStreamContext,
keyManager.getStreamContext(contactId, transportId));
}
@Test
public void testGetStreamContextForPendingContact() throws Exception {
context.checking(new DbExpectations() {{
oneOf(db).transactionWithNullableResult(with(false),
withNullableDbCallable(txn));
oneOf(transportKeyManager).getStreamContext(txn, pendingContactId);
will(returnValue(pendingContactStreamContext));
}});
assertEquals(pendingContactStreamContext,
keyManager.getStreamContext(pendingContactId, transportId));
}
@Test
public void testGetStreamContextForTagAndUnknownTransport()
throws Exception {
@@ -146,10 +191,10 @@ public class KeyManagerImplTest extends BrambleMockTestCase {
oneOf(db).transactionWithNullableResult(with(false),
withNullableDbCallable(txn));
oneOf(transportKeyManager).getStreamContext(txn, tag);
will(returnValue(streamContext));
will(returnValue(contactStreamContext));
}});
assertEquals(streamContext,
assertEquals(contactStreamContext,
keyManager.getStreamContext(transportId, tag));
}

70
bramble-core/src/test/java/org/briarproject/bramble/transport/TransportKeyManagerImplTest.java
View File

@@ -1,6 +1,7 @@
package org.briarproject.bramble.transport;
import org.briarproject.bramble.api.contact.ContactId;
import org.briarproject.bramble.api.contact.PendingContactId;
import org.briarproject.bramble.api.crypto.SecretKey;
import org.briarproject.bramble.api.crypto.TransportCrypto;
import org.briarproject.bramble.api.db.DatabaseComponent;
@@ -37,6 +38,7 @@ import static org.briarproject.bramble.api.transport.TransportConstants.PROTOCOL
import static org.briarproject.bramble.api.transport.TransportConstants.REORDERING_WINDOW_SIZE;
import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
import static org.briarproject.bramble.test.TestUtils.getContactId;
import static org.briarproject.bramble.test.TestUtils.getRandomId;
import static org.briarproject.bramble.test.TestUtils.getSecretKey;
import static org.briarproject.bramble.test.TestUtils.getTransportId;
import static org.briarproject.bramble.util.ByteUtils.MAX_32_BIT_UNSIGNED;
@@ -61,6 +63,8 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
private final long timePeriodLength = maxLatency + MAX_CLOCK_DIFFERENCE;
private final ContactId contactId = getContactId();
private final ContactId contactId1 = getContactId();
private final PendingContactId pendingContactId =
new PendingContactId(getRandomId());
private final KeySetId keySetId = new KeySetId(345);
private final KeySetId keySetId1 = new KeySetId(456);
private final SecretKey tagKey = getSecretKey();
@@ -162,7 +166,7 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
public void testHandshakeKeysAreDerivedWhenAddingContact()
throws Exception {
boolean alice = random.nextBoolean();
TransportKeys transportKeys = createTransportKeys(1000, 0, true);
TransportKeys transportKeys = createHandshakeKeys(1000, 0, alice);
Transaction txn = new Transaction(null, false);
context.checking(new Expectations() {{
@@ -193,6 +197,42 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
assertTrue(transportKeyManager.canSendOutgoingStreams(contactId));
}
@Test
public void testHandshakeKeysAreDerivedWhenAddingPendingContact()
throws Exception {
boolean alice = random.nextBoolean();
TransportKeys transportKeys = createHandshakeKeys(1000, 0, alice);
Transaction txn = new Transaction(null, false);
context.checking(new Expectations() {{
// Get the current time (1 ms after start of time period 1000)
oneOf(clock).currentTimeMillis();
will(returnValue(timePeriodLength * 1000 + 1));
// Derive the transport keys
oneOf(transportCrypto).deriveHandshakeKeys(transportId, rootKey,
1000, alice);
will(returnValue(transportKeys));
// Encode the tags (3 sets)
for (long i = 0; i < REORDERING_WINDOW_SIZE; i++) {
exactly(3).of(transportCrypto).encodeTag(
with(any(byte[].class)), with(tagKey),
with(PROTOCOL_VERSION), with(i));
will(new EncodeTagAction());
}
// Save the keys
oneOf(db).addTransportKeys(txn, pendingContactId, transportKeys);
will(returnValue(keySetId));
}});
TransportKeyManager transportKeyManager = new TransportKeyManagerImpl(
db, transportCrypto, dbExecutor, scheduler, clock, transportId,
maxLatency);
assertEquals(keySetId, transportKeyManager.addPendingContact(txn,
pendingContactId, rootKey, alice));
assertTrue(transportKeyManager.canSendOutgoingStreams(
pendingContactId));
}
@Test
public void testOutgoingStreamContextIsNullIfContactIsNotFound()
throws Exception {
@@ -205,6 +245,19 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
assertFalse(transportKeyManager.canSendOutgoingStreams(contactId));
}
@Test
public void testOutgoingStreamContextIsNullIfPendingContactIsNotFound()
throws Exception {
Transaction txn = new Transaction(null, false);
TransportKeyManager transportKeyManager = new TransportKeyManagerImpl(
db, transportCrypto, dbExecutor, scheduler, clock, transportId,
maxLatency);
assertNull(transportKeyManager.getStreamContext(txn, pendingContactId));
assertFalse(transportKeyManager.canSendOutgoingStreams(
pendingContactId));
}
@Test
public void testOutgoingStreamContextIsNullIfStreamCounterIsExhausted()
throws Exception {
@@ -565,6 +618,21 @@ public class TransportKeyManagerImplTest extends BrambleMockTestCase {
return new TransportKeys(transportId, inPrev, inCurr, inNext, outCurr);
}
@SuppressWarnings("SameParameterValue")
private TransportKeys createHandshakeKeys(long timePeriod,
long streamCounter, boolean alice) {
IncomingKeys inPrev = new IncomingKeys(tagKey, headerKey,
timePeriod - 1);
IncomingKeys inCurr = new IncomingKeys(tagKey, headerKey,
timePeriod);
IncomingKeys inNext = new IncomingKeys(tagKey, headerKey,
timePeriod + 1);
OutgoingKeys outCurr = new OutgoingKeys(tagKey, headerKey,
timePeriod, streamCounter, true);
return new TransportKeys(transportId, inPrev, inCurr, inNext, outCurr,
rootKey, alice);
}
private class EncodeTagAction implements Action {
private final Collection<byte[]> tags;