com.amazonaws.encryptionsdk.ParsedCiphertext Maven / Gradle / Ivy
/*
* Copyright 2019 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.encryptionsdk;
import com.amazonaws.encryptionsdk.internal.Utils;
import com.amazonaws.encryptionsdk.model.CiphertextHeaders;
import com.amazonaws.encryptionsdk.exception.BadCiphertextException;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
* Exposes header information of ciphertexts to make it easier to inspect the algorithm, keys, and
* encryption context prior to decryption.
*
* Please note that the class does not make defensive copies.
*/
public class ParsedCiphertext extends CiphertextHeaders {
private final byte[] ciphertext_;
private final int offset_;
/**
* Parses {@code ciphertext}. Please note that this does not make a defensive copy of
* {@code ciphertext} and that any changes made to the backing array will be reflected here as
* well.
*
* @param ciphertext The ciphertext to parse
* @param maxEncryptedDataKeys The maximum number of encrypted data keys to parse.
* Zero indicates no maximum.
*/
public ParsedCiphertext(final byte[] ciphertext, final int maxEncryptedDataKeys) {
ciphertext_ = Utils.assertNonNull(ciphertext, "ciphertext");
offset_ = deserialize(ciphertext_, 0, maxEncryptedDataKeys);
if (!this.isComplete()) {
throw new BadCiphertextException("Incomplete ciphertext.");
}
}
/**
* Parses {@code ciphertext} without enforcing a max EDK count. Please note that this does
* not make a defensive copy of {@code ciphertext} and that any changes made to the
* backing array will be reflected here as well.
*/
public ParsedCiphertext(final byte[] ciphertext) {
this(ciphertext, CiphertextHeaders.NO_MAX_ENCRYPTED_DATA_KEYS);
}
/**
* Returns the raw ciphertext backing this object. This is not a defensive copy and so
* must not be modified by callers.
*/
@SuppressFBWarnings("EI_EXPOSE_REP")
public byte[] getCiphertext() {
return ciphertext_;
}
/**
* The offset at which the first non-header byte in {@code ciphertext} is located.
*/
public int getOffset() {
return offset_;
}
}