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/* |
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* This file is part of ArakneUtils. |
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* |
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* ArakneUtils is free software: you can redistribute it and/or modify |
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* it under the terms of the GNU Lesser 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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* ArakneUtils 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 Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public License |
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* along with ArakneUtils. If not, see <https://www.gnu.org/licenses/>. |
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* |
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* Copyright (c) 2017-2020 Vincent Quatrevieux |
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*/ |
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package fr.arakne.utils.encoding; |
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import java.io.UnsupportedEncodingException; |
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import java.net.URLDecoder; |
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import java.net.URLEncoder; |
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import java.nio.charset.StandardCharsets; |
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/** |
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* Implementation of the xor cipher in Dofus 1 |
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* Note: This cipher is not secure, the key can be easily retrieved. |
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* |
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* https://github.com/Emudofus/Dofus/blob/1.29/dofus/aks/Aks.as#L297 |
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*/ |
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final public class XorCipher { |
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final private String key; |
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public XorCipher(String key) { |
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this.key = key; |
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} |
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/** |
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* Get the key used by the cipher |
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* |
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* @return The key |
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*/ |
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public String key() { |
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return key; |
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} |
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/** |
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* Encrypt the value using using the current key |
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* The encrypted value is an upper case hexadecimal string |
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* |
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* https://github.com/Emudofus/Dofus/blob/1.29/dofus/aks/Aks.as#L297 |
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* |
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* @param value Value to encrypt |
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* @param keyOffset Offset to use for the key |
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* |
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* @return Encrypted value |
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*/ |
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public String encrypt(String value, int keyOffset) { |
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value = escape(value); |
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StringBuilder encrypted = new StringBuilder(value.length() * 2); |
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for (int i = 0; i < value.length(); ++i) { |
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final char c = value.charAt(i); |
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1 |
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final char k = key.charAt((i + keyOffset) % key.length()); |
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final char e = (char) (c ^ k); |
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if (e < 16) { |
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encrypted.append('0'); |
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} |
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encrypted.append(Integer.toHexString(e)); |
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} |
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return encrypted.toString().toUpperCase(); |
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} |
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/** |
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* Decrypt the value using the current key |
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* |
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* https://github.com/Emudofus/Dofus/blob/1.29/dofus/aks/Aks.as#L314 |
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* |
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* @param value Value to decrypt. Must be a valid hexadecimal string |
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* @param keyOffset Offset to use on the key. Must be the same used for encryption. |
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* |
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* @return The decrypted value |
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* |
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* @throws IllegalArgumentException When an invalid string is given |
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* @throws NumberFormatException When an invalid hexadecimal string is given |
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*/ |
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public String decrypt(String value, int keyOffset) { |
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if (value.length() % 2 != 0) { |
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throw new IllegalArgumentException("Invalid encrypted value"); |
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} |
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char[] decrypted = new char[value.length() / 2]; |
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for (int i = 0; i < value.length(); i += 2) { |
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final char k = key.charAt((i / 2 + keyOffset) % key.length()); |
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final char c = (char) Integer.parseInt(value.substring(i, i + 2), 16); |
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decrypted[i / 2] = (char) (c ^ k); |
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} |
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try { |
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return URLDecoder.decode(new String(decrypted), StandardCharsets.UTF_8.toString()); |
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} catch (UnsupportedEncodingException e) { |
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throw new IllegalArgumentException("Invalid UTF-8 character", e); |
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} |
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} |
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/** |
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* Escape value using URL encode |
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* |
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* https://github.com/Emudofus/Dofus/blob/1.29/dofus/aks/Aks.as#L275 |
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*/ |
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static private String escape(String value) { |
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StringBuilder escaped = new StringBuilder(value.length()); |
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try { |
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for (int i = 0; i < value.length(); ++i) { |
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final char c = value.charAt(i); |
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if (c < 32 || c > 127 || c == '%' || c == '+') { |
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escaped.append(URLEncoder.encode(String.valueOf(c), StandardCharsets.UTF_8.toString())); |
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} else { |
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escaped.append(c); |
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} |
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} |
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} catch (UnsupportedEncodingException e) { |
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throw new IllegalArgumentException("Invalid UTF-8 character", e); |
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} |
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return escaped.toString(); |
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} |
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} |
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Arakne /
ArakneUtils
