/*
* 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.nio.ByteBuffer;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;
/**
* This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) for
* cryptographic ciphers.
* <p>
* Implementers of cryptographic ciphers must implement all the abstract methods
* for every cipher they implement. {@code CipherSpi} instances are created
* along with ciphers when the {@link Cipher#getInstance} method is called. A
* {@code Cipher} is referenced by a <i>transformation</i>, which is a string
* that describes the operation (or set of operations), always consisting of the
* cipher's name and optionally followed by a mode and a padding, in the form:
* <ul>
* <li>"algorithm"</li>or
* <li>"algorithm/mode/padding"</li>
* </ul>
* The following behavior should be implemented for obtaining {@code Cipher}
* instances.
* <p>
* When one of the {@link Cipher#getInstance} factory methods is called with a
* <i>transformation</i> that is only an <i>algorithm</i>, check if the provider
* defines a {@code CipherSpi} for "algorithm", if so: return it, otherwise
* throw a {@link NoSuchAlgorithmException}.
* <p>
* The following rules apply when a <i>transformation</i> is of the form
* "algorithm/mode/padding":
* <ul>
* 1. The Provider has a {@code CipherSpi} subclass registered for
* "algorithm/mode/padding": return it, otherwise go to step 2.
* </ul>
* <ul>
* 2. The Provider has a {@code CipherSpi} subclass registered for
* "algorithm/mode": instantiate it, call
* {@link CipherSpi#engineSetPadding(String) engineSetPadding(String)} for the
* padding name and return it, otherwise go to step 3.
* </ul>
* <ul>
* 3. The Provider has a {@code CipherSpi} subclass registered for
* "algorithm//padding": instantiate it, call
* {@link CipherSpi#engineSetMode(String) engineSetMode(String)} for the mode
* name and return it, otherwise go to step 4.
* </ul>
* <ul>
* 4. The Provider has a {@code CipherSpi} subclass registered for "algorithm":
* instantiate it, call {@link CipherSpi#engineSetMode(String)
* engineSetMode(String)} for the mode name , call
* {@link CipherSpi#engineSetPadding(String) engineSetPadding(String)} for the
* padding name and return it, otherwise throw a
* {@link NoSuchAlgorithmException}.
* </ul>
*
* @see Cipher
*/
public abstract class CipherSpi {
/**
* Creates a new {@code CipherSpi} instance.
*/
public CipherSpi() {
}
/**
* Sets the mode for this cipher.
*
* @param mode
* the name of the cipher mode.
* @throws NoSuchAlgorithmException
* if the specified cipher mode is not supported by this
* provider.
*/
protected abstract void engineSetMode(String mode)
throws NoSuchAlgorithmException;
/**
* Sets the padding method for this cipher.
*
* @param padding
* the name of the padding method.
* @throws NoSuchPaddingException
* if the specified padding method is not supported by this
* cipher.
*/
protected abstract void engineSetPadding(String padding)
throws NoSuchPaddingException;
/**
* Returns the block size of this cipher (in bytes)
*
* @return the block size of this cipher, or zero if this cipher is not a
* block cipher.
*/
protected abstract int engineGetBlockSize();
/**
* Returns the size for a buffer (in bytes), that the next call to {@code
* update} of {@code doFinal} would return, taking into account any buffered
* data from previous {@code update} calls and padding.
* <p>
* The actual output length of the next call to {@code update} or {@code
* doFinal} may be smaller than the length returned by this method.
*
* @param inputLen
* the length of the input (in bytes).
* @return the size for a buffer (in bytes).
*/
protected abstract int engineGetOutputSize(int inputLen);
/**
* Returns the Initialization Vector (IV) that was used to initialize this
* cipher or {@code null} if none was used.
*
* @return the Initialization Vector (IV), or {@code null} if none was used.
*/
protected abstract byte[] engineGetIV();
/**
* Returns the parameters that where used to create this cipher instance.
* <p>
* These may be a the same parameters that were used to create this cipher
* instance, or may be a combination of default and random parameters,
* depending on the underlying cipher implementation.
*
* @return the parameters that where used to create this cipher instance, or
* {@code null} if this cipher instance does not have any parameters
* at all.
*/
protected abstract AlgorithmParameters engineGetParameters();
/**
* Initializes this cipher instance with the specified key and a source of
* randomness.
* <p>
* The cipher will be initialized for the specified operation (one of:
* encryption, decryption, key wrapping or key unwrapping) depending on
* {@code opmode}.
* <p>
* If this cipher instance needs any algorithm parameters or random values
* that the specified key cannot provide, the underlying implementation of
* this cipher is supposed to generate the required parameters (using its
* provider or random values). Random values will be generated using {@code
* random};
* <p>
* When a cipher instance is initialized by a call to any of the {@code
* init} methods, the state of the instance is overridden, means it is
* equivalent to creating a new instance and calling it {@code init} method.
*
* @param opmode
* the operation this cipher instance should be initialized for
* (one of: {@code ENCRYPT_MODE}, {@code DECRYPT_MODE}, {@code
* WRAP_MODE} or {@code UNWRAP_MODE}).
* @param key
* the input key for the operation.
* @param random
* the source of randomness to use.
* @throws InvalidKeyException
* if the specified key cannot be used to initialize this cipher
* instance.
*/
protected abstract void engineInit(int opmode, Key key, SecureRandom random)
throws InvalidKeyException;
/**
* Initializes this cipher instance with the specified key, algorithm
* parameters and a source of randomness.
* <p>
* The cipher will be initialized for the specified operation (one of:
* encryption, decryption, key wrapping or key unwrapping) depending on
* {@code opmode}.
* <p>
* If this cipher instance needs any algorithm parameters and {@code params}
* is {@code null}, the underlying implementation of this cipher is supposed
* to generate the required parameters (using its provider or random
* values). Random values are generated using {@code random}.
* <p>
* When a cipher instance is initialized by a call to any of the {@code
* init} methods, the state of the instance is overridden, means it is
* equivalent to creating a new instance and calling it {@code init} method.
*
* @param opmode
* the operation this cipher instance should be initialized for
* (one of: {@code ENCRYPT_MODE}, {@code DECRYPT_MODE}, {@code
* WRAP_MODE} or {@code UNWRAP_MODE}).
* @param key
* the input key for the operation.
* @param params
* the algorithm parameters.
* @param random
* the source of randomness to use.
* @throws InvalidKeyException
* if the specified key cannot be used to initialize this cipher
* instance.
* @throws InvalidAlgorithmParameterException
* it the specified parameters are inappropriate for this
* cipher.
*/
protected abstract void engineInit(int opmode, Key key,
AlgorithmParameterSpec params, SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException;
/**
* Initializes this cipher instance with the specified key, algorithm
* parameters and a source of randomness.
* <p>
* The cipher will be initialized for the specified operation (one of:
* encryption, decryption, key wrapping or key unwrapping) depending on
* {@code opmode}.
* <p>
* If this cipher instance needs any algorithm parameters and {@code params}
* is {@code null}, the underlying implementation of this cipher is supposed
* to generate the required parameters (using its provider or random
* values). Random values are generated using {@code random}.
* <p>
* When a cipher instance is initialized by a call to any of the {@code
* init} methods, the state of the instance is overridden, means it is
* equivalent to creating a new instance and calling it {@code init} method.
*
* @param opmode
* the operation this cipher instance should be initialized for
* (one of: {@code ENCRYPT_MODE}, {@code DECRYPT_MODE}, {@code
* WRAP_MODE} or {@code UNWRAP_MODE}).
* @param key
* the input key for the operation.
* @param params
* the algorithm parameters.
* @param random
* the source of randomness to use.
* @throws InvalidKeyException
* if the specified key cannot be used to initialize this cipher
* instance.
* @throws InvalidAlgorithmParameterException
* if the specified parameters are inappropriate for this
* cipher.
*/
protected abstract void engineInit(int opmode, Key key,
AlgorithmParameters params, SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException;
/**
* Continues a multi-part transformation (encryption or decryption). The
* transformed bytes are returned.
*
* @param input
* the input bytes to transform.
* @param inputOffset
* the offset in the input to start.
* @param inputLen
* the length of the input to transform.
* @return the transformed bytes in a new buffer, or {@code null} if the
* input has zero length.
* @throws IllegalStateException
* if this cipher instance is not initialized for encryption or
* decryption.
* @throws IllegalArgumentException
* if the input is null, or if {@code inputOffset} and {@code
* inputLen} do not specify a valid chunk in the input buffer.
*/
protected abstract byte[] engineUpdate(byte[] input, int inputOffset,
int inputLen);
/**
* Continues a multi-part transformation (encryption or decryption). The
* transformed bytes are stored in the {@code output} buffer.
* <p>
* If the size of the {@code output} buffer is too small to hold the result,
* a {@code ShortBufferException} is thrown. Use
* {@link Cipher#getOutputSize getOutputSize} to check for the size of the
* output buffer.
*
* @param input
* the input bytes to transform.
* @param inputOffset
* the offset in the input to start.
* @param inputLen
* the length of the input to transform.
* @param output
* the output buffer.
* @param outputOffset
* the offset in the output buffer.
* @return the number of bytes placed in output.
* @throws ShortBufferException
* if the size of the {@code output} buffer is too small.
*/
protected abstract int engineUpdate(byte[] input, int inputOffset,
int inputLen, byte[] output, int outputOffset)
throws ShortBufferException;
/**
* Continues a multi-part transformation (encryption or decryption). The
* {@code input.remaining()} bytes starting at {@code input.position()} are
* transformed and stored in the {@code output} buffer.
* <p>
* If the {@code output.remaining()} is too small to hold the transformed
* bytes a {@code ShortBufferException} is thrown. Use
* {@link Cipher#getOutputSize getOutputSize} to check for the size of the
* output buffer.
*
* @param input
* the input buffer to transform.
* @param output
* the output buffer to store the result within.
* @return the number of bytes stored in the output buffer.
* @throws ShortBufferException
* if the size of the {@code output} buffer is too small.
*/
protected int engineUpdate(ByteBuffer input, ByteBuffer output)
throws ShortBufferException {
if (input == null) {
throw new NullPointerException("input == null");
}
if (output == null) {
throw new NullPointerException("output == null");
}
int position = input.position();
int limit = input.limit();
if ((limit - position) <= 0) {
return 0;
}
byte[] bInput;
byte[] bOutput;
if (input.hasArray()) {
bInput = input.array();
int offset = input.arrayOffset();
bOutput = engineUpdate(bInput, offset + position, limit - position);
input.position(limit);
} else {
bInput = new byte[limit - position];
input.get(bInput);
bOutput = engineUpdate(bInput, 0, limit - position);
}
if (bOutput == null) {
return 0;
}
if (output.remaining() < bOutput.length) {
throw new ShortBufferException("output buffer too small");
}
try {
output.put(bOutput);
} catch (java.nio.BufferOverflowException e) {
throw new ShortBufferException("output buffer too small");
}
return bOutput.length;
}
/**
* Finishes a multi-part transformation (encryption or decryption).
* <p>
* Processes the {@code inputLen} bytes in {@code input} buffer at {@code
* inputOffset}, and any bytes that have been buffered in previous {@code
* update} calls.
*
* @param input
* the input buffer.
* @param inputOffset
* the offset in the input buffer.
* @param inputLen
* the length of the input.
* @return the final bytes from the transformation.
* @throws IllegalBlockSizeException
* if the size of the resulting bytes is not a multiple of the
* cipher block size.
* @throws BadPaddingException
* if the padding of the data does not match the padding scheme.
*/
protected abstract byte[] engineDoFinal(byte[] input, int inputOffset,
int inputLen) throws IllegalBlockSizeException, BadPaddingException;
/**
* Finishes a multi-part transformation (encryption or decryption).
* <p>
* Processes the {@code inputLen} bytes in {@code input} buffer at
* {@code inputOffset}, and any bytes that have been buffered in previous
* {@code update} calls.
*
* @param input
* the input buffer.
* @param inputOffset
* the offset in the input buffer.
* @param inputLen
* the length of the input.
* @param output
* the output buffer for the transformed bytes.
* @param outputOffset
* the offset in the output buffer.
* @return the number of bytes placed in the output buffer.
* @throws ShortBufferException
* if the size of the {@code output} buffer is too small.
* @throws IllegalBlockSizeException
* if the size of the resulting bytes is not a multiple of the
* cipher block size.
* @throws BadPaddingException
* if the padding of the data does not match the padding scheme.
*/
protected abstract int engineDoFinal(byte[] input, int inputOffset,
int inputLen, byte[] output, int outputOffset)
throws ShortBufferException, IllegalBlockSizeException,
BadPaddingException;
/**
* Finishes a multi-part transformation (encryption or decryption).
* <p>
* Processes the {@code input.remaining()} bytes in {@code input} buffer at
* {@code input.position()}, and any bytes that have been buffered in
* previous {@code update} calls. The transformed bytes are placed into
* {@code output} buffer.
*
* @param input
* the input buffer.
* @param output
* the output buffer.
* @return the number of bytes placed into the output buffer.
* @throws ShortBufferException
* if the size of the {@code output} buffer is too small.
* @throws IllegalBlockSizeException
* if the size of the resulting bytes is not a multiple of the
* cipher block size.
* @throws BadPaddingException
* if the padding of the data does not match the padding scheme.
* @throws IllegalArgumentException
* if the input buffer and the output buffer are the same
* object.
* @throws IllegalStateException
* if this cipher instance is not initialized for encryption or
* decryption.
*/
protected int engineDoFinal(ByteBuffer input, ByteBuffer output)
throws ShortBufferException, IllegalBlockSizeException,
BadPaddingException {
if (input == null) {
throw new NullPointerException("input == null");
}
if (output == null) {
throw new NullPointerException("output == null");
}
int position = input.position();
int limit = input.limit();
if ((limit - position) <= 0) {
return 0;
}
byte[] bInput;
byte[] bOutput;
if (input.hasArray()) {
bInput = input.array();
int offset = input.arrayOffset();
bOutput = engineDoFinal(bInput, offset + position, limit - position);
input.position(limit);
} else {
bInput = new byte[limit - position];
input.get(bInput);
bOutput = engineDoFinal(bInput, 0, limit - position);
}
if (output.remaining() < bOutput.length) {
throw new ShortBufferException("output buffer too small");
}
try {
output.put(bOutput);
} catch (java.nio.BufferOverflowException e) {
throw new ShortBufferException("output buffer too small");
}
return bOutput.length;
}
/**
* Wraps a key using this cipher instance. This method has been added to
* this class (for backwards compatibility, it cannot be abstract). If this
* method is not overridden, it throws an {@code
* UnsupportedOperationException}.
*
* @param key
* the key to wrap.
* @return the wrapped key
* @throws IllegalBlockSizeException
* if the size of the resulting bytes is not a multiple of the
* cipher block size.
* @throws InvalidKeyException
* if this cipher instance cannot wrap this key.
*/
protected byte[] engineWrap(Key key) throws IllegalBlockSizeException, InvalidKeyException {
throw new UnsupportedOperationException();
}
/**
* Unwraps a key using this cipher instance.
* <p>
* This method has been added to this class (for backwards compatibility, it
* cannot be abstract). If this method is not overridden, it throws an
* {@code UnsupportedOperationException}.
*
* @param wrappedKey
* the wrapped key to unwrap.
* @param wrappedKeyAlgorithm
* the algorithm for the wrapped key.
* @param wrappedKeyType
* the type of the wrapped key (one of: {@code SECRET_KEY},
* {@code PRIVATE_KEY} or {@code PUBLIC_KEY})
* @return the unwrapped key.
* @throws InvalidKeyException
* if the {@code wrappedKey} cannot be unwrapped to a key of
* type {@code wrappedKeyType} for the {@code
* wrappedKeyAlgorithm}.
* @throws NoSuchAlgorithmException
* if no provider can be found that can create a key of type
* {@code wrappedKeyType} for the {@code wrappedKeyAlgorithm}.
*/
protected Key engineUnwrap(byte[] wrappedKey, String wrappedKeyAlgorithm,
int wrappedKeyType) throws InvalidKeyException, NoSuchAlgorithmException {
throw new UnsupportedOperationException();
}
/**
* Returns the size of a specified key object in bits. This method has been
* added to this class (for backwards compatibility, it cannot be abstract).
* If this method is not overridden, it throws an {@code
* UnsupportedOperationException}.
*
* @param key
* the key to get the size for.
* @return the size of a specified key object in bits.
* @throws InvalidKeyException
* if the size of the key cannot be determined by this
* implementation.
*/
protected int engineGetKeySize(Key key) throws InvalidKeyException {
throw new UnsupportedOperationException();
}
}