| // Copyright 2017 Google Inc. |
| // |
| // Licensed 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 com.google.crypto.tink.subtle; |
| |
| import java.nio.ByteBuffer; |
| import java.security.GeneralSecurityException; |
| |
| /** |
| * StreamSegmentEncrypter is a helper class that encrypts individual segments of a stream. |
| * |
| * <p>Instances of this interfaces are passed to ...EncryptingChannel. Each instance of a segment |
| * encrypter is used to encrypt one stream. Typically, constructing a new StreamSegmentEncrypter |
| * results in the generation of a new symmetric key. This new symmetric key is used to encrypt the |
| * segments of the stream. The key itself wrapped with or derived from the key from StreamingAead |
| * instance. The wrapped key or the salt used to derive the symmetric key is part of the header. |
| * |
| * <p>A StreamSegmentEncrypter has a state: it keeps the number of segments encrypted so far. This |
| * state is used to encrypt each segment with different parameters, so that segments in the |
| * ciphertext cannot be switched. |
| * |
| * @since 1.1.0 |
| */ |
| public interface StreamSegmentEncrypter { |
| |
| /** |
| * Returns the header of the ciphertext stream. |
| */ |
| ByteBuffer getHeader(); |
| |
| /** |
| * Encrypts the next plaintext segment. |
| * This uses encryptedSegments as the segment number for the encryption. |
| */ |
| void encryptSegment( |
| ByteBuffer plaintext, |
| boolean isLastSegment, |
| ByteBuffer ciphertext) |
| throws GeneralSecurityException; |
| |
| /** |
| * Encrypt a segment consisting of two parts. |
| * This method simplifies the case where one part of the plaintext is buffered and the other part |
| * is passed in by the caller. |
| */ |
| void encryptSegment( |
| ByteBuffer part1, |
| ByteBuffer part2, |
| boolean isLastSegment, |
| ByteBuffer ciphertext) |
| throws GeneralSecurityException; |
| } |
| |