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Code Issues Releases Wiki Activity

Add support for decryption with hidden recipients

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This commit is contained in:
Paul Schaub 2021-01-09 16:16:17 +01:00
parent 9333fa2b65
commit 63bf5a8e69
Signed by: vanitasvitae
GPG key ID: 62BEE9264BF17311
2 changed files with 97 additions and 11 deletions
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44
pgpainless-core/src/main/java/org/pgpainless/decryption_verification/DecryptionStreamFactory.java
View file

@ -33,6 +33,7 @@ import org.bouncycastle.openpgp.PGPCompressedData;
import org.bouncycastle.openpgp.PGPEncryptedData;
import org.bouncycastle.openpgp.PGPEncryptedDataList;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPKeyValidationException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPObjectFactory;
import org.bouncycastle.openpgp.PGPOnePassSignature;
@ -43,6 +44,7 @@ import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyEncryptedData;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPSecretKey;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.PGPUtil;
@ -208,18 +210,38 @@ public final class DecryptionStreamFactory {
} else if (encryptedData instanceof PGPPublicKeyEncryptedData) {
PGPPublicKeyEncryptedData publicKeyEncryptedData = (PGPPublicKeyEncryptedData) encryptedData;
long keyId = publicKeyEncryptedData.getKeyID();
resultBuilder.addRecipientKeyId(keyId);
LOGGER.log(LEVEL, "PGPEncryptedData is encrypted for key " + Long.toHexString(keyId));
if (decryptionKeys != null) {
PGPSecretKey secretKey = decryptionKeys.getSecretKey(keyId);
if (secretKey != null) {
LOGGER.log(LEVEL, "Found respective secret key " + Long.toHexString(keyId));
// Watch out! This assignment is possibly done multiple times.
encryptedSessionKey = publicKeyEncryptedData;
decryptionKey = secretKey.extractPrivateKey(decryptionKeyDecryptor.getDecryptor(keyId));
resultBuilder.setDecryptionFingerprint(new OpenPgpV4Fingerprint(secretKey));
// Known key id
if (keyId != 0) {
LOGGER.log(LEVEL, "PGPEncryptedData is encrypted for key " + Long.toHexString(keyId));
resultBuilder.addRecipientKeyId(keyId);
PGPSecretKey secretKey = decryptionKeys.getSecretKey(keyId);
if (secretKey != null) {
LOGGER.log(LEVEL, "Found respective secret key " + Long.toHexString(keyId));
// Watch out! This assignment is possibly done multiple times.
encryptedSessionKey = publicKeyEncryptedData;
decryptionKey = secretKey.extractPrivateKey(decryptionKeyDecryptor.getDecryptor(keyId));
resultBuilder.setDecryptionFingerprint(new OpenPgpV4Fingerprint(secretKey));
}
} else {
// Hidden recipient
LOGGER.log(LEVEL, "Hidden recipient detected. Try to decrypt with all available secret keys.");
outerloop: for (PGPSecretKeyRing ring : decryptionKeys) {
for (PGPSecretKey key : ring) {
PGPPrivateKey privateKey = key.extractPrivateKey(decryptionKeyDecryptor.getDecryptor(key.getKeyID()));
PublicKeyDataDecryptorFactory decryptorFactory = ImplementationFactory.getInstance().getPublicKeyDataDecryptorFactory(privateKey);
try {
publicKeyEncryptedData.getSymmetricAlgorithm(decryptorFactory); // will only succeed if we have the right secret key
LOGGER.log(LEVEL, "Found correct key " + Long.toHexString(key.getKeyID()) + " for hidden recipient decryption.");
decryptionKey = privateKey;
resultBuilder.setDecryptionFingerprint(new OpenPgpV4Fingerprint(key));
encryptedSessionKey = publicKeyEncryptedData;
break outerloop;
} catch (ClassCastException | PGPKeyValidationException e) {
LOGGER.log(LEVEL, "Skipping wrong key " + Long.toHexString(key.getKeyID()) + " for hidden recipient decryption.", e);
}
}
}
}
}
}

64
pgpainless-core/src/test/java/org/pgpainless/decryption_verification/DecryptHiddenRecipientMessage.java Normal file
View file

@ -0,0 +1,64 @@
/*
* 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 org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
import org.bouncycastle.util.io.Streams;
import org.junit.jupiter.api.Test;
import org.pgpainless.PGPainless;
import org.pgpainless.key.TestKeys;
import org.pgpainless.key.protection.UnprotectedKeysProtector;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class DecryptHiddenRecipientMessage {
private static final String PLAINTEXT = "Hello WOrld";
/**
* Message was created using
* gpg --no-default-keyring --keyring ~/.pgpainless --no-default-recipient --armor --output ~/message.asc --encrypt --hidden-recipient emil@email.user ~/message.txt
* where ~/.pgpainless was a gnupg keyring containing all the test keys and message.asc contained the plaintext message.
*/
private static final String CHIPERHTEXT = "-----BEGIN PGP MESSAGE-----\n" +
"\n" +
"hG4DAAAAAAAAAAASAgMEUif9JYa7qZedAFs0AUUJ3cxdc7tpsREZxhzzFpgWzKbH\n" +
"YB1i7rp3PM9zO88v3GRQY6TH5tR8CJkHRTWGu03c0SBTUbrzWngh0i2uR9DJnjLk\n" +
"B8HD4fgn9VP+Qj5Igg6KJdJSAVZlFqVh0H6PCEUaSre/KlyVVqikZKTm0hnWb6XZ\n" +
"/TrefNuUR6PDNyh/oMbfAQD46UZjfRrbNUdKjOyfwtBYkkcGKTF+HilQbjk1nKud\n" +
"pojSOQ==\n" +
"=nyvJ\n" +
"-----END PGP MESSAGE-----";
@Test
public void testDecryptionWithHiddenRecipient() throws IOException, PGPException {
PGPSecretKeyRingCollection emilSecret = TestKeys.getEmilSecretKeyRingCollection();
DecryptionStream decryptionStream = PGPainless.decryptAndOrVerify().onInputStream(new ByteArrayInputStream(CHIPERHTEXT.getBytes(StandardCharsets.UTF_8)))
.decryptWith(new UnprotectedKeysProtector(), emilSecret)
.doNotVerify()
.build();
ByteArrayOutputStream out = new ByteArrayOutputStream();
Streams.pipeAll(decryptionStream, out);
decryptionStream.close();
OpenPgpMetadata metadata = decryptionStream.getResult();
}
}