gcc/libjava/classpath/javax/crypto/EncryptedPrivateKeyInfo.java

/* EncryptedPrivateKeyInfo.java -- As in PKCS #8.
   Copyright (C) 2004  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package javax.crypto;

import gnu.java.security.OID;
import gnu.java.security.der.DER;
import gnu.java.security.der.DERReader;
import gnu.java.security.der.DERValue;

import java.io.IOException;
import java.security.AlgorithmParameters;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.ArrayList;
import java.util.List;

/**
 * An implementation of the <code>EncryptedPrivateKeyInfo</code> ASN.1
 * type as specified in <a
 * href="http://www.rsasecurity.com/rsalabs/pkcs/pkcs-8/">PKCS #8 -
 * Private-Key Information Syntax Standard</a>.
 *
 * <p>The ASN.1 type <code>EncryptedPrivateKeyInfo</code> is:
 *
 * <blockquote>
 * <pre>EncryptedPrivateKeyInfo ::= SEQUENCE {
 *   encryptionAlgorithm EncryptionAlgorithmIdentifier,
 *   encryptedData EncryptedData }
 *
 * EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
 *
 * EncrytpedData ::= OCTET STRING
 *
 * AlgorithmIdentifier ::= SEQUENCE {
 *   algorithm  OBJECT IDENTIFIER,
 *   parameters ANY DEFINED BY algorithm OPTIONAL }</pre>
 * </blockquote>
 *
 * @author Casey Marshall (csm@gnu.org)
 * @since 1.4
 * @see java.security.spec.PKCS8EncodedKeySpec
 */
public class EncryptedPrivateKeyInfo
{

  // Fields.
  // ------------------------------------------------------------------------

  /** The encrypted data. */
  private byte[] encryptedData;

  /** The encoded, encrypted key. */
  private byte[] encoded;

  /** The OID of the encryption algorithm. */
  private OID algOid;

  /** The encryption algorithm name. */
  private String algName;

  /** The encryption algorithm's parameters. */
  private AlgorithmParameters params;

  /** The encoded ASN.1 algorithm parameters. */
  private byte[] encodedParams;

  // Constructors.
  // ------------------------------------------------------------------------

  /**
   * Create a new <code>EncryptedPrivateKeyInfo</code> object from raw
   * encrypted data and the parameters used for encryption.
   *
   * <p>The <code>encryptedData</code> array is cloned.
   *
   * @param params        The encryption algorithm parameters.
   * @param encryptedData The encrypted key data.
   * @throws java.lang.IllegalArgumentException If the
   *         <code>encryptedData</code> array is empty (zero-length).
   * @throws java.security.NoSuchAlgorithmException If the algorithm
   *         specified in the parameters is not supported.
   * @throws java.lang.NullPointerException If <code>encryptedData</code>
   *         is null.
   */
  public EncryptedPrivateKeyInfo(AlgorithmParameters params,
                                 byte[] encryptedData)
    throws IllegalArgumentException, NoSuchAlgorithmException
  {
    if (encryptedData.length == 0)
      {
        throw new IllegalArgumentException("0-length encryptedData");
      }
    this.params = params;
    algName = params.getAlgorithm ();
    algOid = getOid (algName);
    this.encryptedData = (byte[]) encryptedData.clone();
  }

  /**
   * Create a new <code>EncryptedPrivateKeyInfo</code> from an encoded
   * representation, parsing the ASN.1 sequence.
   *
   * @param encoded The encoded info.
   * @throws java.io.IOException If parsing the encoded data fails.
   * @throws java.lang.NullPointerException If <code>encoded</code> is
   *         null.
   */
  public EncryptedPrivateKeyInfo(byte[] encoded)
    throws IOException
  {
    this.encoded = (byte[]) encoded.clone();
    decode();
  }

  /**
   * Create a new <code>EncryptedPrivateKeyInfo</code> from the cipher
   * name and the encrytpedData.
   *
   * <p>The <code>encryptedData</code> array is cloned.
   *
   * @param algName       The name of the algorithm (as an object identifier).
   * @param encryptedData The encrypted key data.
   * @throws java.lang.IllegalArgumentException If the
   *         <code>encryptedData</code> array is empty (zero-length).
   * @throws java.security.NoSuchAlgorithmException If algName is not
   *         the name of a supported algorithm.
   * @throws java.lang.NullPointerException If <code>encryptedData</code>
   *         is null.
   */
  public EncryptedPrivateKeyInfo(String algName, byte[] encryptedData)
    throws IllegalArgumentException, NoSuchAlgorithmException,
           NullPointerException
  {
    if (encryptedData.length == 0)
      {
        throw new IllegalArgumentException("0-length encryptedData");
      }
    this.algName = algName.toString (); // do NP check
    this.algOid = getOid (algName);
    this.encryptedData = (byte[]) encryptedData.clone();
  }

  /**
   * Return the OID for the given cipher name.
   *
   * @param str The string.
   * @throws NoSuchAlgorithmException If the OID is not known.
   */
  private static OID getOid (final String str)
    throws NoSuchAlgorithmException
  {
    if (str.equalsIgnoreCase ("DSA"))
      {
        return new OID ("1.2.840.10040.4.3");
      }
    // FIXME add more

    try
      {
        return new OID (str);
      }
    catch (Throwable t)
      {
      }
    throw new NoSuchAlgorithmException ("cannot determine OID for '" + str + "'");
  }

  // Instance methods.
  // ------------------------------------------------------------------------

  /**
   * Return the name of the cipher used to encrypt this key.
   *
   * @return The algorithm name.
   */
  public String getAlgName()
  {
    return algOid.toString();
  }

  public AlgorithmParameters getAlgParameters()
  {
    if (params == null && encodedParams != null)
      {
        try
          {
            params = AlgorithmParameters.getInstance(getAlgName());
            params.init(encodedParams);
          }
        catch (NoSuchAlgorithmException ignore)
          {
            // FIXME throw exception?
          }
        catch (IOException ignore)
          {
          }
      }
    return params;
  }

  public synchronized byte[] getEncoded() throws IOException
  {
    if (encoded == null) encode();
    return (byte[]) encoded.clone();
  }

  public byte[] getEncryptedData()
  {
    return encryptedData;
  }

  public PKCS8EncodedKeySpec getKeySpec(Cipher cipher)
    throws InvalidKeySpecException
  {
    try
      {
        return new PKCS8EncodedKeySpec(cipher.doFinal(encryptedData));
      }
    catch (Exception x)
      {
        throw new InvalidKeySpecException(x.toString());
      }
  }

  // Own methods.
  // -------------------------------------------------------------------------

  private void decode() throws IOException
  {
    DERReader der = new DERReader(encoded);
    DERValue val = der.read();
    if (val.getTag() != DER.SEQUENCE)
      throw new IOException("malformed EncryptedPrivateKeyInfo");
    val = der.read();
    if (val.getTag() != DER.SEQUENCE)
      throw new IOException("malformed AlgorithmIdentifier");
    int algpLen = val.getLength();
    DERValue oid = der.read();
    if (oid.getTag() != DER.OBJECT_IDENTIFIER)
      throw new IOException("malformed AlgorithmIdentifier");
    algOid = (OID) oid.getValue();
    if (algpLen == 0)
      {
        val = der.read();
        if (val.getTag() != 0)
          {
            encodedParams = val.getEncoded();
            der.read();
          }
      }
    else if (oid.getEncodedLength() < val.getLength())
      {
        val = der.read();
        encodedParams = val.getEncoded();
      }
    val = der.read();
    if (val.getTag() != DER.OCTET_STRING)
      throw new IOException("malformed AlgorithmIdentifier");
    encryptedData = (byte[]) val.getValue();
  }

  private void encode() throws IOException
  {
    List algId = new ArrayList(2);
    algId.add(new DERValue(DER.OBJECT_IDENTIFIER, algOid));
    getAlgParameters();
    if (params != null)
      {
        algId.add (DERReader.read (params.getEncoded()));
      }
    else
      {
        algId.add (new DERValue (DER.NULL, null));
      }
    List epki = new ArrayList(2);
    epki.add(new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, algId));
    epki.add(new DERValue(DER.OCTET_STRING, encryptedData));
    encoded = new DERValue(DER.CONSTRUCTED|DER.SEQUENCE, epki).getEncoded();
  }
}