java_src/src/test/java/com/google/crypto/tink/hybrid/internal/X25519HpkeKemPrivateKeyTest.java

// Copyright 2022 Google LLC
//
// 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 com.google.crypto.tink.hybrid.internal;

import static org.junit.Assert.assertThrows;

import com.google.common.truth.Expect;
import com.google.crypto.tink.subtle.X25519;
import com.google.crypto.tink.util.Bytes;
import java.security.GeneralSecurityException;
import java.util.Arrays;
import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Unit tests for {@link X25519HpkeKemPrivateKey}. */
@RunWith(JUnit4.class)
public final class X25519HpkeKemPrivateKeyTest {

  private static byte[] privateKeyBytes;
  private static byte[] publicKeyBytes;

  @Rule public final Expect expect = Expect.create();

  @BeforeClass
  public static void generateKeyMaterial() throws GeneralSecurityException {
    privateKeyBytes = X25519.generatePrivateKey();
    publicKeyBytes = X25519.publicFromPrivate(privateKeyBytes);
  }

  @Test
  public void createX25519KemPrivateKey_fromValidPrivateKey_succeeds()
      throws GeneralSecurityException {
    X25519HpkeKemPrivateKey privateKey = X25519HpkeKemPrivateKey.fromBytes(privateKeyBytes);
    expect.that(privateKey.getSerializedPrivate()).isEqualTo(Bytes.copyFrom(privateKeyBytes));
    expect.that(privateKey.getSerializedPublic()).isEqualTo(Bytes.copyFrom(publicKeyBytes));
  }

  @Test
  public void createX25519KemPrivateKey_fromInvalidPrivateKey_fails()
      throws GeneralSecurityException {
    assertThrows(
        GeneralSecurityException.class,
        () ->
            X25519HpkeKemPrivateKey.fromBytes(
                Arrays.copyOf(privateKeyBytes, privateKeyBytes.length + 2)));
  }
}