/*
* 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 javax.crypto;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import libcore.io.IoUtils;
/**
* A {@code SealedObject} is a wrapper around a {@code serializable} object
* instance and encrypts it using a cryptographic cipher.
*
* <p>Since a {@code SealedObject} instance is serializable it can
* either be stored or transmitted over an insecure channel.
*
* <p>The wrapped object can later be decrypted (unsealed) using the corresponding
* key and then be deserialized to retrieve the original object. The sealed
* object itself keeps track of the cipher and corresponding parameters.
*/
public class SealedObject implements Serializable {
private static final long serialVersionUID = 4482838265551344752L;
/**
* The cipher's {@link AlgorithmParameters} in encoded format.
* Equivalent to {@code cipher.getParameters().getEncoded()},
* or null if the cipher did not use any parameters.
*/
protected byte[] encodedParams;
private byte[] encryptedContent;
private String sealAlg;
private String paramsAlg;
private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
// This implementation is based on the latest recommendations for safe deserialization at
// the time of writing. See the Serialization spec section A.6.
ObjectInputStream.GetField fields = s.readFields();
// The mutable byte arrays are cloned and the immutable strings are not.
this.encodedParams = getSafeCopy(fields, "encodedParams");
this.encryptedContent = getSafeCopy(fields, "encryptedContent");
this.paramsAlg = (String) fields.get("paramsAlg", null);
this.sealAlg = (String) fields.get("sealAlg", null);
}
private static byte[] getSafeCopy(ObjectInputStream.GetField fields, String fieldName)
throws IOException {
byte[] fieldValue = (byte[]) fields.get(fieldName, null);
return fieldValue != null ? fieldValue.clone() : null;
}
/**
* Creates a new {@code SealedObject} instance wrapping the specified object
* and sealing it using the specified cipher.
* <p>
* The cipher must be fully initialized.
*
* @param object
* the object to seal, can be {@code null}.
* @param c
* the cipher to encrypt the object.
* @throws IOException
* if the serialization fails.
* @throws IllegalBlockSizeException
* if the specified cipher is a block cipher and the length of
* the serialized data is not a multiple of the ciphers block
* size.
* @throws NullPointerException
* if the cipher is {@code null}.
*/
public SealedObject(Serializable object, Cipher c)
throws IOException, IllegalBlockSizeException {
if (c == null) {
throw new NullPointerException("c == null");
}
ObjectOutputStream oos = null;
try {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
oos = new ObjectOutputStream(bos);
oos.writeObject(object);
oos.flush();
AlgorithmParameters ap = c.getParameters();
this.encodedParams = (ap == null) ? null : ap.getEncoded();
this.paramsAlg = (ap == null) ? null : ap.getAlgorithm();
this.sealAlg = c.getAlgorithm();
this.encryptedContent = c.doFinal(bos.toByteArray());
} catch (BadPaddingException e) {
// should be never thrown because the cipher
// should be initialized for encryption
throw new IOException(e.toString());
} finally {
IoUtils.closeQuietly(oos);
}
}
/**
* Creates a new {@code SealedObject} instance by copying the data from
* the specified object.
*
* @param so
* the object to copy.
*/
protected SealedObject(SealedObject so) {
if (so == null) {
throw new NullPointerException("so == null");
}
// For safety: clone the mutable arrays so that each object has its own independent copy of
// the data.
this.encryptedContent = so.encryptedContent != null ? so.encryptedContent.clone() : null;
this.encodedParams = so.encodedParams != null ? so.encodedParams.clone() : null;
this.sealAlg = so.sealAlg;
this.paramsAlg = so.paramsAlg;
}
/**
* Returns the algorithm this object was sealed with.
*
* @return the algorithm this object was sealed with.
*/
public final String getAlgorithm() {
return sealAlg;
}
/**
* Returns the wrapped object, decrypting it using the specified key.
*
* @param key
* the key to decrypt the data with.
* @return the encapsulated object.
* @throws IOException
* if deserialization fails.
* @throws ClassNotFoundException
* if deserialization fails.
* @throws NoSuchAlgorithmException
* if the algorithm to decrypt the data is not available.
* @throws InvalidKeyException
* if the specified key cannot be used to decrypt the data.
*/
public final Object getObject(Key key)
throws IOException, ClassNotFoundException,
NoSuchAlgorithmException, InvalidKeyException {
if (key == null) {
throw new InvalidKeyException("key == null");
}
try {
Cipher cipher = Cipher.getInstance(sealAlg);
if ((paramsAlg != null) && (paramsAlg.length() != 0)) {
AlgorithmParameters params = AlgorithmParameters.getInstance(paramsAlg);
params.init(encodedParams);
cipher.init(Cipher.DECRYPT_MODE, key, params);
} else {
cipher.init(Cipher.DECRYPT_MODE, key);
}
byte[] serialized = cipher.doFinal(encryptedContent);
return readSerialized(serialized);
} catch (NoSuchPaddingException e) {
// should not be thrown because cipher text was made
// with existing padding
throw new NoSuchAlgorithmException(e.toString());
} catch (InvalidAlgorithmParameterException e) {
// should not be thrown because cipher text was made
// with correct algorithm parameters
throw new NoSuchAlgorithmException(e.toString());
} catch (IllegalBlockSizeException e) {
// should not be thrown because the cipher text
// was correctly made
throw new NoSuchAlgorithmException(e.toString());
} catch (BadPaddingException e) {
// should not be thrown because the cipher text
// was correctly made
throw new NoSuchAlgorithmException(e.toString());
} catch (IllegalStateException e) {
// should never be thrown because cipher is initialized
throw new NoSuchAlgorithmException(e.toString());
}
}
/**
* Returns the wrapped object, decrypting it using the specified
* cipher.
*
* @param c
* the cipher to decrypt the data.
* @return the encapsulated object.
* @throws IOException
* if deserialization fails.
* @throws ClassNotFoundException
* if deserialization fails.
* @throws IllegalBlockSizeException
* if the specified cipher is a block cipher and the length of
* the serialized data is not a multiple of the ciphers block
* size.
* @throws BadPaddingException
* if the padding of the data does not match the padding scheme.
*/
public final Object getObject(Cipher c)
throws IOException, ClassNotFoundException,
IllegalBlockSizeException, BadPaddingException {
if (c == null) {
throw new NullPointerException("c == null");
}
byte[] serialized = c.doFinal(encryptedContent);
return readSerialized(serialized);
}
/**
* Returns the wrapped object, decrypting it using the specified key. The
* specified provider is used to retrieve the cipher algorithm.
*
* @param key
* the key to decrypt the data.
* @param provider
* the name of the provider that provides the cipher algorithm.
* @return the encapsulated object.
* @throws IOException
* if deserialization fails.
* @throws ClassNotFoundException
* if deserialization fails.
* @throws NoSuchAlgorithmException
* if the algorithm used to decrypt the data is not available.
* @throws NoSuchProviderException
* if the specified provider is not available.
* @throws InvalidKeyException
* if the specified key cannot be used to decrypt the data.
*/
public final Object getObject(Key key, String provider)
throws IOException, ClassNotFoundException,
NoSuchAlgorithmException, NoSuchProviderException,
InvalidKeyException {
if (provider == null || provider.isEmpty()) {
throw new IllegalArgumentException("provider name empty or null");
}
try {
Cipher cipher = Cipher.getInstance(sealAlg, provider);
if ((paramsAlg != null) && (paramsAlg.length() != 0)) {
AlgorithmParameters params = AlgorithmParameters.getInstance(paramsAlg);
params.init(encodedParams);
cipher.init(Cipher.DECRYPT_MODE, key, params);
} else {
cipher.init(Cipher.DECRYPT_MODE, key);
}
byte[] serialized = cipher.doFinal(encryptedContent);
return readSerialized(serialized);
} catch (NoSuchPaddingException e) {
// should not be thrown because cipher text was made
// with existing padding
throw new NoSuchAlgorithmException(e.toString());
} catch (InvalidAlgorithmParameterException e) {
// should not be thrown because cipher text was made
// with correct algorithm parameters
throw new NoSuchAlgorithmException(e.toString());
} catch (IllegalBlockSizeException e) {
// should not be thrown because the cipher text
// was correctly made
throw new NoSuchAlgorithmException(e.toString());
} catch (BadPaddingException e) {
// should not be thrown because the cipher text
// was correctly made
throw new NoSuchAlgorithmException(e.toString());
} catch (IllegalStateException e) {
// should never be thrown because cipher is initialized
throw new NoSuchAlgorithmException(e.toString());
}
}
private static Object readSerialized(byte[] serialized)
throws IOException, ClassNotFoundException {
ObjectInputStream ois = null;
try {
ois = new ObjectInputStream(new ByteArrayInputStream(serialized));
return ois.readObject();
} finally {
IoUtils.closeQuietly(ois);
}
}
}