org.khannex.action.MakeSign.java Source code

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Here is the source code for org.khannex.action.MakeSign.java

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/*
 * Copyright 2016 David Lukacs
 *
 * 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 org.khannex.action;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Base64;
import java.util.Optional;

import org.apache.commons.codec.digest.DigestUtils;
import org.khannex.io.BerSequenceBuilder;
import org.khannex.io.CardIO;
import org.khannex.io.Response;

public class MakeSign extends Command {

    @Override
    public Response execute(Context context) {
        Response retval = null;

        final Optional<String> param = getNextParam();
        if (param.isPresent()) {
            final CardIO cardio = new CardIO();
            try {
                final byte[] digest = DigestUtils.sha1(param.get());
                final byte[] pin = readPin().getBytes();

                cardio.connect();
                cardio.transmitReset().assertSuccessful();
                cardio.transmitSelectDf(new byte[] { 0x50, 0x11 }).assertSuccessful();
                cardio.transmitSelectDf(new byte[] { (byte) 0x90, 0x02 }).assertSuccessful();
                cardio.transmitVerify(pin).assertSuccessful();
                cardio.transmitSelectPrivateKey().assertSuccessful();
                final byte[] signature = cardio.transmitSign(digest).assertSuccessful().getData();

                final String result = Base64.getEncoder().encodeToString(getBerEncodedResult(digest, signature));
                retval = response().withResult(result).build();
            } catch (Exception ex) {
                context.setException(ex);

                retval = response().build();
            } finally {
                cardio.disconnect();
            }
        }

        return retval;
    }

    private String readPin() throws IOException {
        return new String(Files.readAllBytes(Paths.get(System.getProperty("user.home"), ".khpass")));
    }

    /*
     * The result is encoded according to the Basic Encoding Rules for ASN.1
     * Schematic representation as follows:
     * 
     *   SignResult ::= SEQUENCE {
     *     digest OCTET STRING,
     *     signature OCTET STRING
     *   }
     */
    private byte[] getBerEncodedResult(byte[] digest, byte[] signature) {
        return new BerSequenceBuilder().withOctetString(digest).withOctetString(signature).build();
    }

}