| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.sshd.common.kex; |
| |
| import java.security.SecureRandom; |
| import java.util.Arrays; |
| |
| import org.apache.sshd.common.util.security.SecurityUtils; |
| import org.bouncycastle.crypto.AsymmetricCipherKeyPair; |
| import org.bouncycastle.crypto.SecretWithEncapsulation; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimeKEMExtractor; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimeKEMGenerator; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimeKeyGenerationParameters; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimeKeyPairGenerator; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimeParameters; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimePrivateKeyParameters; |
| import org.bouncycastle.pqc.crypto.ntruprime.SNTRUPrimePublicKeyParameters; |
| |
| /** |
| * A Bouncy Castle implementation of the sntrup761 key encapsulation method (KEM). |
| */ |
| final class SNTRUP761 { |
| |
| private SNTRUP761() { |
| // No instantiation |
| } |
| |
| static boolean isSupported() { |
| if (!SecurityUtils.isBouncyCastleRegistered()) { |
| return false; |
| } |
| try { |
| return SNTRUPrimeParameters.sntrup761.getSessionKeySize() == 256; // BC < 1.78 had only 128 |
| } catch (Throwable e) { |
| return false; |
| } |
| } |
| |
| static class Client implements KeyEncapsulationMethod.Client { |
| |
| private SNTRUPrimeKEMExtractor extractor; |
| private SNTRUPrimePublicKeyParameters publicKey; |
| |
| Client() { |
| super(); |
| } |
| |
| @Override |
| public void init() { |
| SNTRUPrimeKeyPairGenerator gen = new SNTRUPrimeKeyPairGenerator(); |
| gen.init(new SNTRUPrimeKeyGenerationParameters(new SecureRandom(), SNTRUPrimeParameters.sntrup761)); |
| AsymmetricCipherKeyPair pair = gen.generateKeyPair(); |
| extractor = new SNTRUPrimeKEMExtractor((SNTRUPrimePrivateKeyParameters) pair.getPrivate()); |
| publicKey = (SNTRUPrimePublicKeyParameters) pair.getPublic(); |
| } |
| |
| @Override |
| public byte[] getPublicKey() { |
| return publicKey.getEncoded(); |
| } |
| |
| @Override |
| public byte[] extractSecret(byte[] encapsulated) { |
| if (encapsulated.length != extractor.getEncapsulationLength()) { |
| throw new IllegalArgumentException("KEM encpsulation has wrong length: " + encapsulated.length); |
| } |
| return extractor.extractSecret(encapsulated); |
| } |
| |
| @Override |
| public int getEncapsulationLength() { |
| return extractor.getEncapsulationLength(); |
| } |
| } |
| |
| static class Server implements KeyEncapsulationMethod.Server { |
| |
| private SecretWithEncapsulation value; |
| |
| Server() { |
| super(); |
| } |
| |
| @Override |
| public byte[] init(byte[] publicKey) { |
| int pkBytes = SNTRUPrimeParameters.sntrup761.getPublicKeyBytes(); |
| if (publicKey.length < pkBytes) { |
| throw new IllegalArgumentException("KEM public key too short: " + publicKey.length); |
| } |
| byte[] pk = Arrays.copyOf(publicKey, pkBytes); |
| SNTRUPrimeKEMGenerator kemGenerator = new SNTRUPrimeKEMGenerator(new SecureRandom()); |
| SNTRUPrimePublicKeyParameters params = new SNTRUPrimePublicKeyParameters(SNTRUPrimeParameters.sntrup761, pk); |
| value = kemGenerator.generateEncapsulated(params); |
| return Arrays.copyOfRange(publicKey, pkBytes, publicKey.length); |
| } |
| |
| @Override |
| public byte[] getSecret() { |
| return value.getSecret(); |
| } |
| |
| @Override |
| public byte[] getEncapsulation() { |
| return value.getEncapsulation(); |
| } |
| |
| } |
| } |