pgpainless/pgpainless-core/src/main/java/org/pgpainless/decryption_verification/MessageInspector.java

104 lines
3.8 KiB
Java

/*
* Copyright 2021 Paul Schaub.
*
* 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.pgpainless.decryption_verification;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.bouncycastle.openpgp.PGPCompressedData;
import org.bouncycastle.openpgp.PGPEncryptedData;
import org.bouncycastle.openpgp.PGPEncryptedDataList;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPObjectFactory;
import org.bouncycastle.openpgp.PGPPBEEncryptedData;
import org.bouncycastle.openpgp.PGPPublicKeyEncryptedData;
import org.pgpainless.implementation.ImplementationFactory;
import org.pgpainless.util.ArmorUtils;
/**
* Inspect an OpenPGP message to determine IDs of its encryption keys or whether it is passphrase protected.
*/
public final class MessageInspector {
public static class EncryptionInfo {
private final List<Long> keyIds = new ArrayList<>();
private boolean isPassphraseEncrypted = false;
public List<Long> getKeyIds() {
return Collections.unmodifiableList(keyIds);
}
public boolean isPassphraseEncrypted() {
return isPassphraseEncrypted;
}
}
private MessageInspector() {
}
/**
* Parses parts of the provided OpenPGP message in order to determine which keys were used to encrypt it.
* Note: This method does not rewind the passed in Stream, so you might need to take care of that yourselves.
*
* @param dataIn openpgp message
* @return encryption information
* @throws IOException
* @throws PGPException
*/
public static EncryptionInfo determineEncryptionInfoForMessage(InputStream dataIn) throws IOException, PGPException {
InputStream decoded = ArmorUtils.getDecoderStream(dataIn);
EncryptionInfo info = new EncryptionInfo();
collectDecryptionKeyIDs(decoded, info);
return info;
}
private static void collectDecryptionKeyIDs(InputStream dataIn, EncryptionInfo info) throws PGPException {
PGPObjectFactory objectFactory = new PGPObjectFactory(dataIn,
ImplementationFactory.getInstance().getKeyFingerprintCalculator());
for (Object next : objectFactory) {
if (next instanceof PGPEncryptedDataList) {
PGPEncryptedDataList encryptedDataList = (PGPEncryptedDataList) next;
for (PGPEncryptedData encryptedData : encryptedDataList) {
if (encryptedData instanceof PGPPublicKeyEncryptedData) {
PGPPublicKeyEncryptedData pubKeyEncryptedData = (PGPPublicKeyEncryptedData) encryptedData;
info.keyIds.add(pubKeyEncryptedData.getKeyID());
} else if (encryptedData instanceof PGPPBEEncryptedData) {
info.isPassphraseEncrypted = true;
}
}
}
if (next instanceof PGPCompressedData) {
PGPCompressedData compressed = (PGPCompressedData) next;
InputStream decompressed = compressed.getDataStream();
collectDecryptionKeyIDs(decompressed, info);
}
if (next instanceof PGPLiteralData) {
return;
}
}
}
}