pgpainless/pgpainless-core/src/main/java/org/pgpainless/key/generation/KeyRingBuilder.java

383 lines
16 KiB
Java

/*
* Copyright 2018 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.key.generation;
import java.nio.charset.Charset;
import java.security.InvalidAlgorithmParameterException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.annotation.Nonnull;
import org.bouncycastle.openpgp.PGPEncryptedData;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPKeyPair;
import org.bouncycastle.openpgp.PGPKeyRingGenerator;
import org.bouncycastle.openpgp.PGPPrivateKey;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPSecretKey;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.PGPSignatureGenerator;
import org.bouncycastle.openpgp.PGPSignatureSubpacketVector;
import org.bouncycastle.openpgp.operator.PBESecretKeyDecryptor;
import org.bouncycastle.openpgp.operator.PBESecretKeyEncryptor;
import org.bouncycastle.openpgp.operator.PGPContentSignerBuilder;
import org.bouncycastle.openpgp.operator.PGPDigestCalculator;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPContentSignerBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPDigestCalculatorProviderBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPKeyPair;
import org.bouncycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePBESecretKeyEncryptorBuilder;
import org.pgpainless.algorithm.HashAlgorithm;
import org.pgpainless.algorithm.KeyFlag;
import org.pgpainless.algorithm.SignatureType;
import org.pgpainless.key.collection.PGPKeyRing;
import org.pgpainless.key.generation.type.ECDH;
import org.pgpainless.key.generation.type.ECDSA;
import org.pgpainless.key.generation.type.KeyType;
import org.pgpainless.key.generation.type.RSA;
import org.pgpainless.key.generation.type.curve.EllipticCurve;
import org.pgpainless.key.generation.type.length.RsaLength;
import org.pgpainless.provider.ProviderFactory;
import org.pgpainless.util.Passphrase;
public class KeyRingBuilder implements KeyRingBuilderInterface {
private final Charset UTF8 = Charset.forName("UTF-8");
private List<KeySpec> keySpecs = new ArrayList<>();
private String userId;
private Set<String> additionalUserIds = new LinkedHashSet<>();
private Passphrase passphrase;
/**
* Creates a simple, unencrypted RSA KeyPair of length {@code length} with user-id {@code userId}.
* The KeyPair consists of a single RSA master key which is used for signing, encryption and certification.
*
* @param userId user id.
* @param length length in bits.
*
* @return {@link PGPSecretKeyRing} containing the KeyPair.
*
* @throws PGPException
* @throws NoSuchAlgorithmException
* @throws InvalidAlgorithmParameterException
*/
public PGPKeyRing simpleRsaKeyRing(@Nonnull String userId, @Nonnull RsaLength length)
throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
return simpleRsaKeyRing(userId, length, null);
}
/**
* Creates a simple RSA KeyPair of length {@code length} with user-id {@code userId}.
* The KeyPair consists of a single RSA master key which is used for signing, encryption and certification.
*
* @param userId user id.
* @param length length in bits.
* @param password Password of the key. Can be null for unencrypted keys.
*
* @return {@link PGPSecretKeyRing} containing the KeyPair.
*
* @throws PGPException
* @throws NoSuchAlgorithmException
* @throws InvalidAlgorithmParameterException
*/
public PGPKeyRing simpleRsaKeyRing(@Nonnull String userId, @Nonnull RsaLength length, String password)
throws PGPException, NoSuchAlgorithmException, InvalidAlgorithmParameterException {
WithAdditionalUserIdOrPassphrase builder = this
.withMasterKey(
KeySpec.getBuilder(RSA.withLength(length))
.withDefaultKeyFlags()
.withDefaultAlgorithms())
.withPrimaryUserId(userId);
if (password == null) {
return builder.withoutPassphrase().build();
} else {
return builder.withPassphrase(new Passphrase(password.toCharArray())).build();
}
}
/**
* Creates an unencrypted key ring consisting of an ECDSA master key and an ECDH sub-key.
* The ECDSA master key is used for signing messages and certifying the sub key.
* The ECDH sub-key is used for encryption of messages.
*
* @param userId user-id
*
* @return {@link PGPSecretKeyRing} containing the key pairs.
*
* @throws PGPException
* @throws NoSuchAlgorithmException
* @throws InvalidAlgorithmParameterException
*/
public PGPKeyRing simpleEcKeyRing(@Nonnull String userId)
throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, PGPException {
return simpleEcKeyRing(userId, null);
}
/**
* Creates a key ring consisting of an ECDSA master key and an ECDH sub-key.
* The ECDSA master key is used for signing messages and certifying the sub key.
* The ECDH sub-key is used for encryption of messages.
*
* @param userId user-id
* @param password Password of the private key. Can be null for an unencrypted key.
*
* @return {@link PGPSecretKeyRing} containing the key pairs.
*
* @throws PGPException
* @throws NoSuchAlgorithmException
* @throws InvalidAlgorithmParameterException
*/
public PGPKeyRing simpleEcKeyRing(@Nonnull String userId, String password)
throws PGPException, NoSuchAlgorithmException, InvalidAlgorithmParameterException {
WithAdditionalUserIdOrPassphrase builder = this
.withSubKey(
KeySpec.getBuilder(ECDH.fromCurve(EllipticCurve._P256))
.withKeyFlags(KeyFlag.ENCRYPT_STORAGE, KeyFlag.ENCRYPT_COMMS)
.withDefaultAlgorithms())
.withMasterKey(
KeySpec.getBuilder(ECDSA.fromCurve(EllipticCurve._P256))
.withKeyFlags(KeyFlag.AUTHENTICATION, KeyFlag.CERTIFY_OTHER, KeyFlag.SIGN_DATA)
.withDefaultAlgorithms())
.withPrimaryUserId(userId);
if (password == null) {
return builder.withoutPassphrase().build();
} else {
return builder.withPassphrase(new Passphrase(password.toCharArray())).build();
}
}
@Override
public KeyRingBuilderInterface withSubKey(@Nonnull KeySpec type) {
KeyRingBuilder.this.keySpecs.add(type);
return this;
}
@Override
public WithPrimaryUserId withMasterKey(@Nonnull KeySpec spec) {
verifyMasterKeyCanCertify(spec);
KeyRingBuilder.this.keySpecs.add(0, spec);
return new WithPrimaryUserIdImpl();
}
private void verifyMasterKeyCanCertify(KeySpec spec) {
if (!canCertifyOthers(spec)) {
throw new IllegalArgumentException("Certification Key MUST have KeyFlag CERTIFY_OTHER");
}
}
private boolean canCertifyOthers(KeySpec keySpec) {
int flags = keySpec.getSubpackets().getKeyFlags();
return KeyFlag.hasKeyFlag(flags, KeyFlag.CERTIFY_OTHER);
}
class WithPrimaryUserIdImpl implements WithPrimaryUserId {
@Override
public WithAdditionalUserIdOrPassphrase withPrimaryUserId(@Nonnull String userId) {
KeyRingBuilder.this.userId = userId.trim();
return new WithAdditionalUserIdOrPassphraseImpl();
}
@Override
public WithAdditionalUserIdOrPassphrase withPrimaryUserId(@Nonnull byte[] userId) {
return withPrimaryUserId(new String(userId, UTF8));
}
}
class WithAdditionalUserIdOrPassphraseImpl implements WithAdditionalUserIdOrPassphrase {
@Override
public WithAdditionalUserIdOrPassphrase withAdditionalUserId(@Nonnull String userId) {
String trimmed = userId.trim();
if (KeyRingBuilder.this.userId.equals(trimmed)) {
throw new IllegalArgumentException("Additional user-id MUST NOT be equal to primary user-id.");
}
KeyRingBuilder.this.additionalUserIds.add(trimmed);
return this;
}
@Override
public WithAdditionalUserIdOrPassphrase withAdditionalUserId(@Nonnull byte[] userId) {
return withAdditionalUserId(new String(userId, UTF8));
}
@Override
public Build withPassphrase(@Nonnull Passphrase passphrase) {
KeyRingBuilder.this.passphrase = passphrase;
return new BuildImpl();
}
@Override
public Build withoutPassphrase() {
KeyRingBuilder.this.passphrase = null;
return new BuildImpl();
}
class BuildImpl implements Build {
private PGPSignatureGenerator signatureGenerator;
private PGPDigestCalculator digestCalculator;
private PBESecretKeyEncryptor secretKeyEncryptor;
@Override
public PGPKeyRing build() throws NoSuchAlgorithmException, PGPException,
InvalidAlgorithmParameterException {
digestCalculator = buildDigestCalculator();
secretKeyEncryptor = buildSecretKeyEncryptor();
PBESecretKeyDecryptor secretKeyDecryptor = buildSecretKeyDecryptor();
if (passphrase != null) {
passphrase.clear();
}
// First key is the Master Key
KeySpec certKeySpec = keySpecs.remove(0);
// Generate Master Key
PGPKeyPair certKey = generateKeyPair(certKeySpec);
PGPContentSignerBuilder signer = buildContentSigner(certKey);
signatureGenerator = new PGPSignatureGenerator(signer);
PGPSignatureSubpacketVector hashedSubPackets = certKeySpec.getSubpackets();
// Generator which the user can get the key pair from
PGPKeyRingGenerator ringGenerator = buildRingGenerator(certKey, signer, hashedSubPackets);
addSubKeys(ringGenerator);
// Generate secret key ring with only primary user id
PGPSecretKeyRing secretKeyRing = ringGenerator.generateSecretKeyRing();
Iterator<PGPSecretKey> secretKeys = secretKeyRing.getSecretKeys();
// Attempt to add additional user-ids to the primary public key
PGPPublicKey primaryPubKey = secretKeys.next().getPublicKey();
PGPPrivateKey privateKey = secretKeyRing.getSecretKey().extractPrivateKey(secretKeyDecryptor);
for (String additionalUserId : additionalUserIds) {
signatureGenerator.init(SignatureType.POSITIVE_CERTIFICATION.getCode(), privateKey);
PGPSignature additionalUserIdSignature =
signatureGenerator.generateCertification(additionalUserId, primaryPubKey);
primaryPubKey = PGPPublicKey.addCertification(primaryPubKey,
additionalUserId, additionalUserIdSignature);
}
// "reassemble" secret key ring with modified primary key
PGPSecretKey primarySecKey = new PGPSecretKey(
privateKey,
primaryPubKey, digestCalculator, true, secretKeyEncryptor);
List<PGPSecretKey> secretKeyList = new ArrayList<>();
secretKeyList.add(primarySecKey);
while (secretKeys.hasNext()) {
secretKeyList.add(secretKeys.next());
}
secretKeyRing = new PGPSecretKeyRing(secretKeyList);
// extract public key ring from secret keys
List<PGPPublicKey> publicKeyList = new ArrayList<>();
Iterator<PGPPublicKey> publicKeys = secretKeyRing.getPublicKeys();
while (publicKeys.hasNext()) {
publicKeyList.add(publicKeys.next());
}
PGPPublicKeyRing publicKeyRing = new PGPPublicKeyRing(publicKeyList);
return new PGPKeyRing(publicKeyRing, secretKeyRing);
}
private PGPKeyRingGenerator buildRingGenerator(PGPKeyPair certKey,
PGPContentSignerBuilder signer,
PGPSignatureSubpacketVector hashedSubPackets)
throws PGPException {
return new PGPKeyRingGenerator(
SignatureType.POSITIVE_CERTIFICATION.getCode(), certKey,
userId, digestCalculator,
hashedSubPackets, null, signer, secretKeyEncryptor);
}
private void addSubKeys(PGPKeyRingGenerator ringGenerator)
throws NoSuchAlgorithmException, PGPException, InvalidAlgorithmParameterException {
for (KeySpec subKeySpec : keySpecs) {
PGPKeyPair subKey = generateKeyPair(subKeySpec);
if (subKeySpec.isInheritedSubPackets()) {
ringGenerator.addSubKey(subKey);
} else {
ringGenerator.addSubKey(subKey, subKeySpec.getSubpackets(), null);
}
}
}
private PGPContentSignerBuilder buildContentSigner(PGPKeyPair certKey) {
return new JcaPGPContentSignerBuilder(
certKey.getPublicKey().getAlgorithm(), HashAlgorithm.SHA512.getAlgorithmId())
.setProvider(ProviderFactory.getProvider());
}
private PBESecretKeyEncryptor buildSecretKeyEncryptor() {
PBESecretKeyEncryptor encryptor = passphrase == null ?
null : // unencrypted key pair, otherwise AES-256 encrypted
new JcePBESecretKeyEncryptorBuilder(PGPEncryptedData.AES_256, digestCalculator)
.setProvider(ProviderFactory.getProvider())
.build(passphrase.getChars());
return encryptor;
}
private PBESecretKeyDecryptor buildSecretKeyDecryptor() throws PGPException {
PBESecretKeyDecryptor decryptor = passphrase == null ?
null :
new JcePBESecretKeyDecryptorBuilder()
.build(passphrase.getChars());
return decryptor;
}
private PGPDigestCalculator buildDigestCalculator() throws PGPException {
return new JcaPGPDigestCalculatorProviderBuilder()
.setProvider(ProviderFactory.getProvider())
.build()
.get(HashAlgorithm.SHA1.getAlgorithmId());
}
private PGPKeyPair generateKeyPair(KeySpec spec)
throws NoSuchAlgorithmException, PGPException,
InvalidAlgorithmParameterException {
KeyType type = spec.getKeyType();
KeyPairGenerator certKeyGenerator = KeyPairGenerator.getInstance(type.getName(), ProviderFactory.getProvider());
certKeyGenerator.initialize(type.getAlgorithmSpec());
// Create raw Key Pair
KeyPair keyPair = certKeyGenerator.generateKeyPair();
// Form PGP key pair
PGPKeyPair pgpKeyPair = new JcaPGPKeyPair(type.getAlgorithm().getAlgorithmId(),
keyPair, new Date());
return pgpKeyPair;
}
}
}
}