1// 2// Copyright (C) 2011 The Android Open Source Project 3// 4// Licensed under the Apache License, Version 2.0 (the "License"); 5// you may not use this file except in compliance with the License. 6// You may obtain a copy of the License at 7// 8// http://www.apache.org/licenses/LICENSE-2.0 9// 10// Unless required by applicable law or agreed to in writing, software 11// distributed under the License is distributed on an "AS IS" BASIS, 12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13// See the License for the specific language governing permissions and 14// limitations under the License. 15// 16 17#include "shill/crypto_rot47.h" 18 19using std::string; 20 21namespace shill { 22 23const char CryptoROT47::kID[] = "rot47"; 24 25CryptoROT47::CryptoROT47() {} 26 27string CryptoROT47::GetID() { 28 return kID; 29} 30 31bool CryptoROT47::Encrypt(const string& plaintext, string* ciphertext) { 32 const int kRotSize = 94; 33 const int kRotHalf = kRotSize / 2; 34 const char kRotMin = '!'; 35 const char kRotMax = kRotMin + kRotSize - 1; 36 37 *ciphertext = plaintext; 38 for (auto& ch : *ciphertext) { 39 if (ch < kRotMin || ch > kRotMax) { 40 continue; 41 } 42 int rot = ch + kRotHalf; 43 ch = (rot > kRotMax) ? rot - kRotSize : rot; 44 } 45 return true; 46} 47 48bool CryptoROT47::Decrypt(const string& ciphertext, string* plaintext) { 49 // ROT47 is self-reciprocal. 50 return Encrypt(ciphertext, plaintext); 51} 52 53} // namespace shill 54