org.bitcoinj.wallet.KeyChain Maven / Gradle / Ivy
/*
* Copyright 2013 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.bitcoinj.wallet;
import org.bitcoinj.core.BloomFilter;
import org.bitcoinj.core.ECKey;
import org.bitcoinj.wallet.listeners.KeyChainEventListener;
import java.util.List;
import java.util.concurrent.Executor;
/**
* A KeyChain is a class that stores a collection of keys for a {@link Wallet}. Key chains
* are expected to be able to look up keys given a hash (i.e. address) or pubkey bytes, and provide keys on request
* for a given purpose. They can inform event listeners about new keys being added.
*
* However it is important to understand what this interface does not provide. It cannot encrypt or decrypt
* keys, for instance you need an implementor of {@link EncryptableKeyChain}. It cannot have keys imported into it,
* that you to use a method of a specific key chain instance, such as {@link BasicKeyChain}. The reason for these
* restrictions is to support key chains that may be handled by external hardware or software, or which are derived
* deterministically from a seed (and thus the notion of importing a key is meaningless).
*/
public interface KeyChain {
/** Returns true if the given key is in the chain. */
boolean hasKey(ECKey key);
enum KeyPurpose {
RECEIVE_FUNDS,
CHANGE,
REFUND,
AUTHENTICATION
}
/** Obtains a number of key/s intended for the given purpose. The chain may create new key/s, derive, or re-use an old one. */
List getKeys(KeyPurpose purpose, int numberOfKeys);
/** Obtains a key intended for the given purpose. The chain may create a new key, derive one, or re-use an old one. */
ECKey getKey(KeyPurpose purpose);
/** Returns a list of keys serialized to the bitcoinj protobuf format. */
List serializeToProtobuf();
/** Adds a listener for events that are run when keys are added, on the user thread. */
void addEventListener(KeyChainEventListener listener);
/** Adds a listener for events that are run when keys are added, on the given executor. */
void addEventListener(KeyChainEventListener listener, Executor executor);
/** Removes a listener for events that are run when keys are added. */
boolean removeEventListener(KeyChainEventListener listener);
/** Returns the number of keys this key chain manages. */
int numKeys();
/**
* Returns the number of elements this chain wishes to insert into the Bloom filter. The size passed to
* {@link #getFilter(int, double, long)} should be at least this large.
*/
int numBloomFilterEntries();
/**
* Returns the earliest creation time of keys in this chain, in seconds since the epoch. This can return zero
* if at least one key does not have that data (was created before key timestamping was implemented). If there
* are no keys in the wallet, {@link Long#MAX_VALUE} is returned.
*/
long getEarliestKeyCreationTime();
/**
* Gets a bloom filter that contains all of the public keys from this chain, and which will provide the given
* false-positive rate if it has size elements. Keep in mind that you will get 2 elements in the bloom filter for
* each key in the key chain, for the public key and the hash of the public key (address form). For this reason
* size should be at least 2x the result of {@link #numKeys()}.
*
* This is used to generate a {@link BloomFilter} which can be {@link BloomFilter#merge(BloomFilter)}d with
* another. It could also be used if you have a specific target for the filter's size.
*
* See the docs for {@link BloomFilter#BloomFilter(int, double, long)} for a brief
* explanation of anonymity when using bloom filters, and for the meaning of these parameters.
*/
BloomFilter getFilter(int size, double falsePositiveRate, long tweak);
}