53 lines
1.4 KiB
C++
53 lines
1.4 KiB
C++
//
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// Copyright (C) 2011 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "shill/crypto_rot47.h"
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using std::string;
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namespace shill {
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const char CryptoROT47::kID[] = "rot47";
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CryptoROT47::CryptoROT47() {}
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string CryptoROT47::GetID() {
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return kID;
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}
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bool CryptoROT47::Encrypt(const string& plaintext, string* ciphertext) {
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const int kRotSize = 94;
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const int kRotHalf = kRotSize / 2;
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const char kRotMin = '!';
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const char kRotMax = kRotMin + kRotSize - 1;
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*ciphertext = plaintext;
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for (auto& ch : *ciphertext) {
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if (ch < kRotMin || ch > kRotMax) {
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continue;
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}
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int rot = ch + kRotHalf;
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ch = (rot > kRotMax) ? rot - kRotSize : rot;
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}
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return true;
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}
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bool CryptoROT47::Decrypt(const string& ciphertext, string* plaintext) {
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// ROT47 is self-reciprocal.
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return Encrypt(ciphertext, plaintext);
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}
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} // namespace shill
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