/**
* Pre-generate enough keys to reach the lookahead size, but only if there are more than the
* lookaheadThreshold to be generated, so that the Bloom filter does not have to be regenerated
* that often.
*
* <p>The returned mutable list of keys must be inserted into the basic key chain.
*/
private List<DeterministicKey> maybeLookAhead(
DeterministicKey parent, int issued, int lookaheadSize, int lookaheadThreshold) {
checkState(lock.isHeldByCurrentThread());
final int numChildren = hierarchy.getNumChildren(parent.getPath());
final int needed = issued + lookaheadSize + lookaheadThreshold - numChildren;
if (needed <= lookaheadThreshold) return new ArrayList<DeterministicKey>();
log.info(
"{} keys needed for {} = {} issued + {} lookahead size + {} lookahead threshold - {} num children",
needed,
parent.getPathAsString(),
issued,
lookaheadSize,
lookaheadThreshold,
numChildren);
List<DeterministicKey> result = new ArrayList<DeterministicKey>(needed);
long now = System.currentTimeMillis();
int nextChild = numChildren;
for (int i = 0; i < needed; i++) {
DeterministicKey key = HDKeyDerivation.deriveThisOrNextChildKey(parent, nextChild);
key = key.getPubOnly();
hierarchy.putKey(key);
result.add(key);
nextChild = key.getChildNumber().num() + 1;
}
log.info("Took {} msec", System.currentTimeMillis() - now);
return result;
}
/**
* Pre-generate enough keys to reach the lookahead size. You can call this if you need to
* explicitly invoke the lookahead procedure, but it's normally unnecessary as it will be done
* automatically when needed.
*/
public void maybeLookAhead() {
lock.lock();
try {
List<DeterministicKey> keys = maybeLookAhead(externalKey, issuedExternalKeys);
keys.addAll(maybeLookAhead(internalKey, issuedInternalKeys));
// Batch add all keys at once so there's only one event listener invocation, as this will be
// listened to
// by the wallet and used to rebuild/broadcast the Bloom filter. That's expensive so we don't
// want to do
// it more often than necessary.
basicKeyChain.importKeys(keys);
} finally {
lock.unlock();
}
}
// For internal usage only
/* package */ List<ECKey> getKeys(boolean includeLookahead) {
List<ECKey> keys = basicKeyChain.getKeys();
if (!includeLookahead) {
int treeSize = internalKey.getPath().size();
List<ECKey> issuedKeys = new LinkedList<ECKey>();
for (ECKey key : keys) {
DeterministicKey detkey = (DeterministicKey) key;
DeterministicKey parent = detkey.getParent();
if (parent == null) continue;
if (detkey.getPath().size() <= treeSize) continue;
if (parent.equals(internalKey) && detkey.getChildNumber().i() > issuedInternalKeys)
continue;
if (parent.equals(externalKey) && detkey.getChildNumber().i() > issuedExternalKeys)
continue;
issuedKeys.add(detkey);
}
return issuedKeys;
}
return keys;
}
/**
* Returns all the key chains found in the given list of keys. Typically there will only be one,
* but in the case of key rotation it can happen that there are multiple chains found.
*/
public static List<DeterministicKeyChain> fromProtobuf(
List<Protos.Key> keys, @Nullable KeyCrypter crypter) throws UnreadableWalletException {
List<DeterministicKeyChain> chains = newLinkedList();
DeterministicSeed seed = null;
DeterministicKeyChain chain = null;
int lookaheadSize = -1;
for (Protos.Key key : keys) {
final Protos.Key.Type t = key.getType();
if (t == Protos.Key.Type.DETERMINISTIC_MNEMONIC) {
if (chain != null) {
checkState(lookaheadSize >= 0);
chain.setLookaheadSize(lookaheadSize);
chain.maybeLookAhead();
chains.add(chain);
chain = null;
}
long timestamp = key.getCreationTimestamp() / 1000;
String passphrase = DEFAULT_PASSPHRASE_FOR_MNEMONIC; // FIXME allow non-empty passphrase
if (key.hasSecretBytes()) {
seed = new DeterministicSeed(key.getSecretBytes().toStringUtf8(), passphrase, timestamp);
} else if (key.hasEncryptedData()) {
EncryptedData data =
new EncryptedData(
key.getEncryptedData().getInitialisationVector().toByteArray(),
key.getEncryptedData().getEncryptedPrivateKey().toByteArray());
seed = new DeterministicSeed(data, timestamp);
} else {
throw new UnreadableWalletException("Malformed key proto: " + key.toString());
}
if (log.isDebugEnabled()) log.debug("Deserializing: DETERMINISTIC_MNEMONIC: {}", seed);
} else if (t == Protos.Key.Type.DETERMINISTIC_KEY) {
if (!key.hasDeterministicKey())
throw new UnreadableWalletException(
"Deterministic key missing extra data: " + key.toString());
byte[] chainCode = key.getDeterministicKey().getChainCode().toByteArray();
// Deserialize the path through the tree.
LinkedList<ChildNumber> path = newLinkedList();
for (int i : key.getDeterministicKey().getPathList()) path.add(new ChildNumber(i));
// Deserialize the public key and path.
ECPoint pubkey = ECKey.CURVE.getCurve().decodePoint(key.getPublicKey().toByteArray());
final ImmutableList<ChildNumber> immutablePath = ImmutableList.copyOf(path);
// Possibly create the chain, if we didn't already do so yet.
boolean isWatchingAccountKey = false;
boolean isFollowingKey = false;
// save previous chain if any if the key is marked as following. Current key and the next
// ones are to be
// placed in new following key chain
if (key.getDeterministicKey().getIsFollowing()) {
if (chain != null) {
checkState(lookaheadSize >= 0);
chain.setLookaheadSize(lookaheadSize);
chain.maybeLookAhead();
chains.add(chain);
chain = null;
seed = null;
}
isFollowingKey = true;
}
if (chain == null) {
if (seed == null) {
DeterministicKey accountKey =
new DeterministicKey(immutablePath, chainCode, pubkey, null, null);
if (!accountKey.getPath().equals(ACCOUNT_ZERO_PATH))
throw new UnreadableWalletException(
"Expecting account key but found key with path: "
+ HDUtils.formatPath(accountKey.getPath()));
chain = new DeterministicKeyChain(accountKey, isFollowingKey);
isWatchingAccountKey = true;
} else {
chain = new DeterministicKeyChain(seed, crypter);
chain.lookaheadSize = LAZY_CALCULATE_LOOKAHEAD;
// If the seed is encrypted, then the chain is incomplete at this point. However, we
// will load
// it up below as we parse in the keys. We just need to check at the end that we've
// loaded
// everything afterwards.
}
}
// Find the parent key assuming this is not the root key, and not an account key for a
// watching chain.
DeterministicKey parent = null;
if (!path.isEmpty() && !isWatchingAccountKey) {
ChildNumber index = path.removeLast();
parent = chain.hierarchy.get(path, false, false);
path.add(index);
}
DeterministicKey detkey;
if (key.hasSecretBytes()) {
// Not encrypted: private key is available.
final BigInteger priv = new BigInteger(1, key.getSecretBytes().toByteArray());
detkey = new DeterministicKey(immutablePath, chainCode, pubkey, priv, parent);
} else {
if (key.hasEncryptedData()) {
Protos.EncryptedData proto = key.getEncryptedData();
EncryptedData data =
new EncryptedData(
proto.getInitialisationVector().toByteArray(),
proto.getEncryptedPrivateKey().toByteArray());
checkNotNull(crypter, "Encountered an encrypted key but no key crypter provided");
detkey = new DeterministicKey(immutablePath, chainCode, crypter, pubkey, data, parent);
} else {
// No secret key bytes and key is not encrypted: either a watching key or private key
// bytes
// will be rederived on the fly from the parent.
detkey = new DeterministicKey(immutablePath, chainCode, pubkey, null, parent);
}
}
if (key.hasCreationTimestamp())
detkey.setCreationTimeSeconds(key.getCreationTimestamp() / 1000);
if (log.isDebugEnabled()) log.debug("Deserializing: DETERMINISTIC_KEY: {}", detkey);
if (!isWatchingAccountKey) {
// If the non-encrypted case, the non-leaf keys (account, internal, external) have already
// been
// rederived and inserted at this point and the two lines below are just a no-op. In the
// encrypted
// case though, we can't rederive and we must reinsert, potentially building the heirarchy
// object
// if need be.
if (path.size() == 0) {
// Master key.
chain.rootKey = detkey;
chain.hierarchy = new DeterministicHierarchy(detkey);
} else if (path.size() == 2) {
if (detkey.getChildNumber().num() == 0) {
chain.externalKey = detkey;
chain.issuedExternalKeys = key.getDeterministicKey().getIssuedSubkeys();
lookaheadSize = Math.max(lookaheadSize, key.getDeterministicKey().getLookaheadSize());
} else if (detkey.getChildNumber().num() == 1) {
chain.internalKey = detkey;
chain.issuedInternalKeys = key.getDeterministicKey().getIssuedSubkeys();
}
}
}
chain.hierarchy.putKey(detkey);
chain.basicKeyChain.importKey(detkey);
}
}
if (chain != null) {
checkState(lookaheadSize >= 0);
chain.setLookaheadSize(lookaheadSize);
chain.maybeLookAhead();
chains.add(chain);
}
return chains;
}
/** Returns freshly derived key/s that have not been returned by this method before. */
@Override
public List<DeterministicKey> getKeys(KeyPurpose purpose, int numberOfKeys) {
checkArgument(numberOfKeys > 0);
lock.lock();
try {
DeterministicKey parentKey;
int index;
switch (purpose) {
// Map both REFUND and RECEIVE_KEYS to the same branch for now. Refunds are a feature of
// the BIP 70
// payment protocol. Later we may wish to map it to a different branch (in a new wallet
// version?).
// This would allow a watching wallet to only be able to see inbound payments, but not
// change
// (i.e. spends) or refunds. Might be useful for auditing ...
case RECEIVE_FUNDS:
case REFUND:
issuedExternalKeys += numberOfKeys;
index = issuedExternalKeys;
parentKey = externalKey;
break;
case AUTHENTICATION:
case CHANGE:
issuedInternalKeys += numberOfKeys;
index = issuedInternalKeys;
parentKey = internalKey;
break;
default:
throw new UnsupportedOperationException();
}
// Optimization: potentially do a very quick key generation for just the number of keys we
// need if we
// didn't already create them, ignoring the configured lookahead size. This ensures we'll be
// able to
// retrieve the keys in the following loop, but if we're totally fresh and didn't get a chance
// to
// calculate the lookahead keys yet, this will not block waiting to calculate 100+ EC point
// multiplies.
// On slow/crappy Android phones looking ahead 100 keys can take ~5 seconds but the OS will
// kill us
// if we block for just one second on the UI thread. Because UI threads may need an address in
// order
// to render the screen, we need getKeys to be fast even if the wallet is totally brand new
// and lookahead
// didn't happen yet.
//
// It's safe to do this because when a network thread tries to calculate a Bloom filter, we'll
// go ahead
// and calculate the full lookahead zone there, so network requests will always use the right
// amount.
List<DeterministicKey> lookahead = maybeLookAhead(parentKey, index, 0, 0);
basicKeyChain.importKeys(lookahead);
List<DeterministicKey> keys = new ArrayList<DeterministicKey>(numberOfKeys);
for (int i = 0; i < numberOfKeys; i++) {
ImmutableList<ChildNumber> path =
HDUtils.append(parentKey.getPath(), new ChildNumber(index - numberOfKeys + i, false));
DeterministicKey k = hierarchy.get(path, false, false);
// Just a last minute sanity check before we hand the key out to the app for usage. This
// isn't inspired
// by any real problem reports from bitcoinj users, but I've heard of cases via the
// grapevine of
// places that lost money due to bitflips causing addresses to not match keys. Of course in
// an
// environment with flaky RAM there's no real way to always win: bitflips could be
// introduced at any
// other layer. But as we're potentially retrieving from long term storage here, check
// anyway.
checkForBitFlip(k);
keys.add(k);
}
return keys;
} finally {
lock.unlock();
}
}
