/**
 * Copyright 2009 Google Inc.
 *
 * 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.waveprotocol.wave.crypto;

import org.apache.commons.codec.binary.Base64;

import java.io.ByteArrayInputStream;
import java.security.GeneralSecurityException;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.spec.EncodedKeySpec;
import java.security.spec.PKCS8EncodedKeySpec;

/**
 * Parses byte arrays into certificates or private keys.
 */
public class CertUtil {

  private CertUtil() {
  }

  public static X509Certificate getCertFromBase64Bytes(String b64cert)
      throws GeneralSecurityException {
    return getCertFromBytes(Base64.decodeBase64(b64cert.getBytes()));
  }

  public static X509Certificate getCertFromBytes(byte[] derCert) throws GeneralSecurityException {
    CertificateFactory fac = CertificateFactory.getInstance("X509");
    ByteArrayInputStream in = new ByteArrayInputStream(derCert);
    X509Certificate cert = (X509Certificate)fac.generateCertificate(in);
    return cert;
  }

  public static PrivateKey getPrivateKeyFromBytes(byte[] derKey) throws GeneralSecurityException {
    KeyFactory fac = KeyFactory.getInstance("RSA");
    EncodedKeySpec privKeySpec = new PKCS8EncodedKeySpec(derKey);
    return fac.generatePrivate(privKeySpec);
  }
}