60 lines
2 KiB
Java
60 lines
2 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.util;
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import java.nio.CharBuffer;
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import java.security.SecureRandom;
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import java.util.Random;
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import java.util.regex.Pattern;
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import android.support.annotation.VisibleForTesting;
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// see https://autocrypt.org/level1.html#setup-code
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public class Numeric9x4PassphraseUtil {
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public static Passphrase generateNumeric9x4Passphrase() {
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return generateNumeric9x4Passphrase(new SecureRandom());
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}
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@VisibleForTesting
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static Passphrase generateNumeric9x4Passphrase(Random r) {
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StringBuilder code = new StringBuilder(36);
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for (int i = 0; i < 36; i++) {
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boolean isBeginningOfBlock = i > 0 && (i % 4) == 0;
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if (isBeginningOfBlock) {
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code.append('-');
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}
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String digit = Integer.toString(r.nextInt(10));
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code.append(digit);
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}
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return new Passphrase(code.toString());
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}
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private static final Pattern AUTOCRYPT_TRANSFER_CODE = Pattern.compile("(\\d{4}-){8}\\d{4}");
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public static boolean isNumeric9x4Passphrase(Passphrase transferCodeChars) {
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return isNumeric9x4Passphrase(CharBuffer.wrap(transferCodeChars.getCharArray()));
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}
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public static boolean isNumeric9x4Passphrase(CharSequence code) {
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return AUTOCRYPT_TRANSFER_CODE.matcher(code).matches();
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}
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}
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