/*
* Copyright 2013-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.services.s3.internal.crypto;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Provider;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.NullCipher;
import javax.crypto.SecretKey;
/**
* Functions like a {@link Cipher} but provides only a subset of all the
* interface methods of {@link Cipher}. This class is intended to be used in
* lieu of the underlying Cipher directly whenever applicable. For example, this
* class makes it easy to generate an inverse cipher, or to create an
* "auxiliary" cipher for use with get-range or multi-part upload operations. A
* subclass may also support the mark and reset operations to enable parts of a
* plaintext to be re-processed which is useful for error recovery typical when
* network transmission is involved.
* <p>
* However a cipher lite, unlike a {@link Cipher}, can only be used once, and
* cannot be reused after the {@link #doFinal()} methods have been invoked. In
* other words, it is NOT true that, upon finishing, the doFinal method will
* reset the cipher lite object to the state it was in when first constructed.
*
* @author Hanson Char
*
* @see GCMCipherLite
*/
class CipherLite {
/**
* A no-op implementation.
*/
static final CipherLite Null = new CipherLite() {
@Override
CipherLite createAuxiliary(long startingBytePos) {
return this;
}
@Override
CipherLite createInverse() {
return this;
}
};
private final Cipher cipher;
private final ContentCryptoScheme scheme;
private final SecretKey secreteKey;
private final int cipherMode;
private CipherLite() {
this.cipher = new NullCipher();
this.scheme = null;
this.secreteKey = null;
this.cipherMode = -1;
}
CipherLite(Cipher cipher, ContentCryptoScheme scheme,
SecretKey secreteKey, int cipherMode) {
this.cipher = cipher;
this.scheme = scheme;
this.secreteKey = secreteKey;
this.cipherMode = cipherMode;
}
/**
* Recreates a new instance of CipherLite from the current one.
*/
CipherLite recreate() {
return scheme.createCipherLite(secreteKey, cipher.getIV(),
this.cipherMode, cipher.getProvider());
}
/**
* Creates a new instance of CipherLite from the current one, but using
* the given IV.
*/
CipherLite createUsingIV(byte[] iv) {
return scheme.createCipherLite(secreteKey, iv, this.cipherMode,
cipher.getProvider());
}
/**
* Returns an auxiliary {@link CipherLite} for partial plaintext
* re-encryption (or re-decryption) purposes.
*
* @param startingBytePos
* the starting byte position of the plaintext. Must be a
* multiple of the cipher block size.
*/
CipherLite createAuxiliary(long startingBytePos)
throws InvalidKeyException, NoSuchAlgorithmException,
NoSuchProviderException, NoSuchPaddingException,
InvalidAlgorithmParameterException {
return scheme.createAuxillaryCipher(secreteKey, cipher.getIV(),
cipherMode, cipher.getProvider(), startingBytePos);
}
/**
* Returns the inverse of the current {@link CipherLite}.
*/
CipherLite createInverse() throws InvalidKeyException,
NoSuchAlgorithmException, NoSuchProviderException,
NoSuchPaddingException, InvalidAlgorithmParameterException {
int inversedMode;
if (cipherMode == Cipher.DECRYPT_MODE)
inversedMode = Cipher.ENCRYPT_MODE;
else if (cipherMode == Cipher.ENCRYPT_MODE)
inversedMode = Cipher.DECRYPT_MODE;
else
throw new UnsupportedOperationException();
return scheme.createCipherLite(secreteKey, cipher.getIV(),
inversedMode, cipher.getProvider());
}
/**
* Finishes a multiple-part encryption or decryption operation, depending on
* how the underlying cipher was initialized.
*
* <p>
* Input data that may have been buffered during a previous
* <code>update</code> operation is processed, with padding (if requested)
* being applied. If an AEAD mode such as GCM/CCM is being used, the
* authentication tag is appended in the case of encryption, or verified in
* the case of decryption. The result is stored in a new buffer.
*
* <p>
* Note: if any exception is thrown, a new instance of this cipher lite
* object may need to be constructed before it can be used again. be
* reconstructed before it can be used again.
*
* @return the new buffer with the result
*
* @exception IllegalStateException
* if this cipher is in a wrong state (e.g., has not been
* initialized)
* @exception IllegalBlockSizeException
* if this cipher is a block cipher, no padding has been
* requested (only in encryption mode), and the total input
* length of the data processed by this cipher is not a
* multiple of block size; or if this encryption algorithm is
* unable to process the input data provided.
* @exception BadPaddingException
* if this cipher is in decryption mode, and (un)padding has
* been requested, but the decrypted data is not bounded by
* the appropriate padding bytes
* @exception BadTagException
* if this cipher is decrypting in an AEAD mode (such as
* GCM/CCM), and the received authentication tag does not
* match the calculated value
*/
byte[] doFinal() throws IllegalBlockSizeException,
BadPaddingException {
return cipher.doFinal();
}
/**
* Encrypts or decrypts data in a single-part operation, or finishes a
* multiple-part operation. The data is encrypted or decrypted, depending on
* how the underlying cipher was initialized.
*
* <p>
* The bytes in the <code>input</code> buffer, and any input bytes that may
* have been buffered during a previous <code>update</code> operation, are
* processed, with padding (if requested) being applied. If an AEAD mode
* such as GCM/CCM is being used, the authentication tag is appended in the
* case of encryption, or verified in the case of decryption. The result is
* stored in a new buffer.
*
* <p>
* Note: if any exception is thrown, a new instance of this cipher lite
* object may need to be constructed before it can be used again.
*
* @param input
* the input buffer
*
* @return the new buffer with the result
*
* @exception IllegalStateException
* if this cipher is in a wrong state (e.g., has not been
* initialized)
* @exception IllegalBlockSizeException
* if this cipher is a block cipher, no padding has been
* requested (only in encryption mode), and the total input
* length of the data processed by this cipher is not a
* multiple of block size; or if this encryption algorithm is
* unable to process the input data provided.
* @exception BadPaddingException
* if this cipher is in decryption mode, and (un)padding has
* been requested, but the decrypted data is not bounded by
* the appropriate padding bytes; or if this cipher is
* decrypting in an AEAD mode (such as GCM/CCM), and the
* received authentication tag does not match the calculated
* value
*/
byte[] doFinal(byte[] input) throws IllegalBlockSizeException,
BadPaddingException {
return cipher.doFinal(input);
}
/**
* Encrypts or decrypts data in a single-part operation, or finishes a
* multiple-part operation. The data is encrypted or decrypted, depending on
* how the underlying cipher was initialized.
*
* <p>
* The first <code>inputLen</code> bytes in the <code>input</code> buffer,
* starting at <code>inputOffset</code> inclusive, and any input bytes that
* may have been buffered during a previous <code>update</code> operation,
* are processed, with padding (if requested) being applied. If an AEAD mode
* such as GCM/CCM is being used, the authentication tag is appended in the
* case of encryption, or verified in the case of decryption. The result is
* stored in a new buffer.
*
* <p>
* Note: if any exception is thrown, a new instance of this cipher lite
* object may need to be constructed before it can be used again.
*
* @param input
* the input buffer
* @param inputOffset
* the offset in <code>input</code> where the input starts
* @param inputLen
* the input length
*
* @return the new buffer with the result
*
* @exception IllegalStateException
* if this cipher is in a wrong state (e.g., has not been
* initialized)
* @exception IllegalBlockSizeException
* if this cipher is a block cipher, no padding has been
* requested (only in encryption mode), and the total input
* length of the data processed by this cipher is not a
* multiple of block size; or if this encryption algorithm is
* unable to process the input data provided.
* @exception BadPaddingException
* if this cipher is in decryption mode, and (un)padding has
* been requested, but the decrypted data is not bounded by
* the appropriate padding bytes; or if this cipher is
* decrypting in an AEAD mode (such as GCM/CCM), and the
* received authentication tag does not match the calculated
* value
*/
byte[] doFinal(byte[] input, int inputOffset, int inputLen)
throws IllegalBlockSizeException, BadPaddingException {
return cipher.doFinal(input, inputOffset, inputLen);
}
/**
* Continues a multiple-part encryption or decryption operation (depending
* on how the underlying cipher was initialized), processing another data
* part.
*
* <p>
* The first <code>inputLen</code> bytes in the <code>input</code> buffer,
* starting at <code>inputOffset</code> inclusive, are processed, and the
* result is stored in a new buffer.
*
* <p>
* If <code>inputLen</code> is zero, this method returns <code>null</code>.
*
* @param input
* the input buffer
* @param inputOffset
* the offset in <code>input</code> where the input starts
* @param inputLen
* the input length
*
* @return the new buffer with the result, or null if the underlying cipher
* is a block cipher and the input data is too short to result in a
* new block.
*
* @exception IllegalStateException
* if the underlying cipher is in a wrong state (e.g., has
* not been initialized)
*/
byte[] update(byte[] input, int inputOffset, int inputLen) {
return cipher.update(input, inputOffset, inputLen);
}
/**
* Returns the algorithm name of the underlying cipher.
*/
final String getCipherAlgorithm() {
return cipher.getAlgorithm();
}
/**
* Returns the provider of the underlying cipher.
*/
final Provider getCipherProvider() {
return cipher.getProvider();
}
/**
* Returns the standard algorithm name for the secret key. For example,
* "DSA" would indicate that this key is a DSA key. See Appendix A in the <a
* href=
* "http://docs.oracle.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html#AppA"
* > Java Cryptography Architecture API Specification & Reference </a>
* for information about standard algorithm names.
*/
final String getSecretKeyAlgorithm() {
return secreteKey.getAlgorithm();
}
/**
* This method is provided only for testing purposes. The {@link CipherLite}
* is intended to be used in lieu of the underlying Cipher.
*/
final Cipher getCipher() {
return cipher;
}
final ContentCryptoScheme getContentCryptoScheme() {
return scheme;
}
/**
* Returns the initialization vector (IV) in a new buffer.
*
* <p>This is useful in the case where a random IV was created,
* or in the context of password-based encryption or
* decryption, where the IV is derived from a user-supplied password.
*
* @return the initialization vector in a new buffer, or null if the
* underlying algorithm does not use an IV, or if the IV has not yet
* been set.
*/
final byte[] getIV() {
return cipher.getIV();
}
/**
* Returns the block size (in bytes).
*
* @return the block size (in bytes), or 0 if the underlying algorithm is
* not a block cipher
*/
final int getBlockSize() {
return cipher.getBlockSize();
}
final int getCipherMode() {
return cipherMode;
}
/**
* Tests if this cipher lite supports the <code>mark</code>
* and <code>reset</code> methods. Returns false by default, but subclass
* may override.
*/
boolean markSupported() { return false; }
/**
* Marks the current position in this cipher lite. A subsequent call to the
* <code>reset</code> method repositions this cipher lite at the last marked
* position so that subsequent crypto operations will be logically performed
* in an idempotent manner as if the cipher has been rewinded back to the
* marked position.
*
* <p>
* The general contract of <code>mark</code> is that, if the method
* <code>markSupported</code> returns <code>true</code>, the cipher lite
* somehow remembers the internal state after the call to <code>mark</code>
* and stands ready to restore to the internal state so that it would be
* able to produce the same output given the same input again if and
* whenever the method <code>reset</code> is called.
*
* @return the current position marked or -1 if mark/reset is not supported.
*/
long mark() { return -1; }
/**
* Repositions this cipher lite to the position at the time the
* <code>mark</code> method was last called.
*
* <p>
* The general contract of <code>reset</code> is:
*
* <p>
* <ul>
* <li>If the method <code>markSupported</code> returns <code>true</code>,
* then the cipher lite is reset to the internal state since the most recent
* call to <code>mark</code> (or since the start of the input data, if
* <code>mark</code> has not been called), so that subsequent callers of the
* <code>udpate</code> or <code>doFinal</code> method would produce the same
* output given the same input data identical to the input data after the
* <code>mark</code> method was last called..</li>
*
* <li>If the method <code>markSupported</code> returns <code>false</code>,
* then the call to <code>reset</code> may throw an
* <code>IllegalStateException</code>.</li>
* </ul>
*/
void reset() {
throw new IllegalStateException("mark/reset not supported");
}
int getOutputSize(int inputLen) {
return cipher.getOutputSize(inputLen);
}
}