ratpack.session.clientside.internal.DefaultCrypto.java Source code

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Here is the source code for ratpack.session.clientside.internal.DefaultCrypto.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 ratpack.session.clientside.internal;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import ratpack.session.clientside.Crypto;
import ratpack.util.Exceptions;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class DefaultCrypto implements Crypto {

    private final SecretKeySpec secretKeySpec;
    private final String algorithm;
    private final boolean isInitializationVectorRequired;

    public DefaultCrypto(byte[] key, String algorithm) {
        String[] parts = algorithm.split("/");
        this.secretKeySpec = new SecretKeySpec(key, parts[0]);
        this.algorithm = algorithm;
        this.isInitializationVectorRequired = parts.length > 1 && !parts[1].equalsIgnoreCase("ECB");
    }

    @Override
    public byte[] encrypt(ByteBuf message) {
        return Exceptions.uncheck(() -> {
            Cipher cipher = Cipher.getInstance(algorithm);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
            ByteBuf messageBuf = Unpooled.wrappedBuffer(new byte[cipher.getOutputSize(message.readableBytes())]);
            cipher.update(message.nioBuffer(), messageBuf.nioBuffer());

            byte[] payload = cipher.doFinal();
            if (isInitializationVectorRequired) {
                byte[] ivBytes = cipher.getIV();
                messageBuf.release();

                int outputLength = 1 + ivBytes.length + payload.length;
                ByteBuf output = Unpooled.wrappedBuffer(new byte[outputLength]).resetWriterIndex()
                        .writeByte(ivBytes.length).writeBytes(ivBytes).writeBytes(payload);

                payload = output.array();

                output.release();
            }

            return payload;
        });
    }

    @Override
    public byte[] decrypt(ByteBuf message) {
        return Exceptions.uncheck(() -> {
            Cipher cipher = Cipher.getInstance(algorithm);

            if (isInitializationVectorRequired) {
                int ivByteLength = message.readByte();
                ByteBuf ivBytes = message.readBytes(ivByteLength);
                IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes.array());
                ivBytes.release();

                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, ivParameterSpec);
            } else {
                cipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
            }

            int messageLength = message.readableBytes();
            ByteBuf output = Unpooled.wrappedBuffer(new byte[cipher.getOutputSize(messageLength)]);
            cipher.update(message.readBytes(messageLength).nioBuffer(), output.nioBuffer());

            byte[] decrypted = cipher.doFinal();
            output.release();

            return decrypted;
        });
    }
}