Line data    Source code

       1             : /*************************************************************************
       2             :  *
       3             :  *  Project
       4             :  *                         _____ _____  __  __ _____
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      10             :  *      | |
      11             :  *      |_|
      12             :  *
      13             :  * Copyright (C) Akiel Aries, <akiel@akiel.org>, et al.
      14             :  *
      15             :  * This software is licensed as described in the file LICENSE, which
      16             :  * you should have received as part of this distribution. The terms
      17             :  * among other details are referenced in the official documentation
      18             :  * seen here : https://akielaries.github.io/openGPMP/ along with
      19             :  * important files seen in this project.
      20             :  *
      21             :  * You may opt to use, copy, modify, merge, publish, distribute
      22             :  * and/or sell copies of the Software, and permit persons to whom
      23             :  * the Software is furnished to do so, under the terms of the
      24             :  * LICENSE file. As this is an Open Source effort, all implementations
      25             :  * must be of the same methodology.
      26             :  *
      27             :  *
      28             :  *
      29             :  * This software is distributed on an AS IS basis, WITHOUT
      30             :  * WARRANTY OF ANY KIND, either express or implied.
      31             :  *
      32             :  ************************************************************************/
      33             : #include <cstdint>
      34             : #include <openGPMP/nt/rc5.hpp>
      35             : 
      36           0 : gpmp::nt::RC5::RC5(uint32_t rounds, uint32_t wordSize, uint32_t blockSize)
      37           0 :     : w(wordSize), r(rounds), b(blockSize) {
      38           0 :     init();
      39           0 : }
      40             : 
      41           0 : void gpmp::nt::RC5::init() {
      42           0 :     S.resize(2 * r + 2);
      43           0 :     S[0] = P;
      44           0 :     for (uint32_t i = 1; i < 2 * r + 2; ++i) {
      45           0 :         S[i] = S[i - 1] + Q;
      46             :     }
      47           0 : }
      48             : 
      49           0 : void gpmp::nt::RC5::encrypt(uint32_t &A, uint32_t &B) {
      50           0 :     A += S[0];
      51           0 :     B += S[1];
      52           0 :     for (uint32_t i = 1; i <= r; ++i) {
      53           0 :         A = rotl((A ^ B), B) + S[2 * i];
      54           0 :         B = rotl((B ^ A), A) + S[2 * i + 1];
      55             :     }
      56           0 : }
      57             : 
      58           0 : void gpmp::nt::RC5::decrypt(uint32_t &A, uint32_t &B) {
      59           0 :     for (uint32_t i = r; i > 0; --i) {
      60           0 :         B = rotr(B - S[2 * i + 1], A) ^ A;
      61           0 :         A = rotr(A - S[2 * i], B) ^ B;
      62             :     }
      63           0 :     B -= S[1];
      64           0 :     A -= S[0];
      65           0 : }
      66             : 
      67           0 : uint32_t gpmp::nt::RC5::rotl(uint32_t value, uint32_t shift) {
      68           0 :     return (value << shift) | (value >> (w - shift));
      69             : }
      70             : 
      71           0 : uint32_t gpmp::nt::RC5::rotr(uint32_t value, uint32_t shift) {
      72           0 :     return (value >> shift) | (value << (w - shift));
      73             : }