47 lines
1.4 KiB
Java
47 lines
1.4 KiB
Java
/*
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* Copyright (C) 2017 Schürmann & Breitmoser GbR
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;
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import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;
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enum BlockChecksumAlgorithm {
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LRC(1), CRC(2);
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private int mLength;
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BlockChecksumAlgorithm(int length) {
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mLength = length;
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}
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public byte[] computeChecksum(byte[] data, int offset, int len) throws UsbTransportException {
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if (this == LRC) {
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byte res = 0;
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for (int i = offset; i < len; i++) {
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res ^= data[i];
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}
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return new byte[]{res};
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} else {
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throw new UsbTransportException("CRC checksum is not implemented");
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}
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}
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public int getLength() {
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return mLength;
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}
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}
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