| // Copyright 2018 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "shill/crypto_rot47.h" |
| |
| using std::string; |
| |
| namespace shill { |
| |
| namespace { |
| constexpr char kId[] = "rot47"; |
| } // namespace |
| |
| CryptoRot47::CryptoRot47() = default; |
| |
| string CryptoRot47::GetId() const { |
| return kId; |
| } |
| |
| bool CryptoRot47::Encrypt(const string& plaintext, string* ciphertext) { |
| const int kRotSize = 94; |
| const int kRotHalf = kRotSize / 2; |
| const char kRotMin = '!'; |
| const char kRotMax = kRotMin + kRotSize - 1; |
| |
| *ciphertext = plaintext; |
| for (auto& ch : *ciphertext) { |
| if (ch < kRotMin || ch > kRotMax) { |
| continue; |
| } |
| int rot = ch + kRotHalf; |
| ch = (rot > kRotMax) ? rot - kRotSize : rot; |
| } |
| return true; |
| } |
| |
| bool CryptoRot47::Decrypt(const string& ciphertext, string* plaintext) { |
| // ROT47 is self-reciprocal. |
| return Encrypt(ciphertext, plaintext); |
| } |
| |
| } // namespace shill |