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2026-06-08 16:52:38 +00:00 · 2017-10-15 19:38:40 +02:00
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+Copyright (c) 2010-2014, Sebastien Andrivet
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from this
+   software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
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+// Copyright (c) 2010-2014, Sebastien Andrivet
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice,
+//    this list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+//    contributors may be used to endorse or promote products derived from this
+//    software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+#include <string>
+#include <array>
+#include <utility>
+#include <cstdarg>
+
+namespace xorstr_impl {
+
+#ifdef _MSC_VER
+#define XORSTR_INLINE __forceinline
+#else
+#define XORSTR_INLINE inline
+#endif
+
+constexpr auto time = __TIME__;
+constexpr auto seed = static_cast<int>(time[7]) +
+                      static_cast<int>(time[6]) * 10 +
+                      static_cast<int>(time[4]) * 60 +
+                      static_cast<int>(time[3]) * 600 +
+                      static_cast<int>(time[1]) * 3600 +
+                      static_cast<int>(time[0]) * 36000;
+
+// 1988, Stephen Park and Keith Miller
+// "Random Number Generators: Good Ones Are Hard To Find", considered as "minimal standard"
+// Park-Miller 31 bit pseudo-random number generator, implemented with G. Carta's optimisation:
+// with 32-bit math and without division
+
+template <int N>
+struct random_generator {
+private:
+  static constexpr unsigned a = 16807;  // 7^5
+  static constexpr unsigned m = 2147483647;  // 2^31 - 1
+  static constexpr unsigned s = random_generator<N - 1>::value;
+  static constexpr unsigned lo = a * (s & 0xFFFF);  // multiply lower 16 bits by 16807
+  static constexpr unsigned hi = a * (s >> 16);  // multiply higher 16 bits by 16807
+  static constexpr unsigned lo2 = lo + ((hi & 0x7FFF) << 16);  // combine lower 15 bits of hi with lo's upper bits
+  static constexpr unsigned hi2 = hi >> 15;  // discard lower 15 bits of hi
+  static constexpr unsigned lo3 = lo2 + hi;
+
+public:
+  static constexpr unsigned max = m;
+  static constexpr unsigned value = lo3 > m ? lo3 - m : lo3;
+};
+
+template <>
+struct random_generator<0> {
+  static constexpr unsigned value = seed;
+};
+
+template <int N, int M>
+struct random_int {
+  static constexpr auto value = random_generator<N + 1>::value % M;
+};
+
+template <int N>
+struct random_char {
+  static const char value = static_cast<char>(1 + random_int<N, 0x7F - 1>::value);
+};
+
+template <size_t N, int K>
+struct string {
+private:
+  const char key_;
+  std::array<char, N + 1> encrypted_;
+
+  constexpr char enc(char c) const {
+    return c ^ key_;
+  }
+
+  char dec(char c) const {
+    return c ^ key_;
+  }
+
+public:
+  template <size_t... Is>
+  constexpr XORSTR_INLINE string(const char* str, std::index_sequence<Is...>) :
+    key_(random_char<K>::value), encrypted_{ { enc(str[Is])... } } {}
+
+  XORSTR_INLINE decltype(auto) decrypt() {
+    for (size_t i = 0; i < N; ++i) {
+      encrypted_[i] = dec(encrypted_[i]);
+    }
+    encrypted_[N] = '\0';
+    return encrypted_.data();
+  }
+};
+
+#undef XORSTR_INLINE
+
+}  // namespace xorstr_impl
+
+#define xorstr(s) (xorstr_impl::string<sizeof(s) - 1, \
+  __COUNTER__>(s, std::make_index_sequence<sizeof(s) - 1>()).decrypt())
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+# XorStr
+A simple constexpr string literal obfuscator. The algorythm was taken from [ADVobfuscator][ADVobfuscator].<br/>
+This technique does not hide strings from sophisticated static analysis tools and memory inspection.
+
+## Usage
+Copy the file <include/xorstr.h> to your project and include it in the source code.
+
+```cpp
+#include <xorstr.h>
+#include <iostream>
+
+int main() {
+  const std::string str = xorstr("xorstr_test_verify_error");
+  std::cout << str << std::endl;
+}
+```
+
+You can verify that the string `xorstr_test_verify_error` does not exist in **Release** builds:
+
+```sh
+~/workspace/xorstr_test strings build/llvm/release/main | grep xorstr_test_verify_error
+~/workspace/xorstr_test strings build/llvm/debug/main | grep xorstr_test_verify_error
+xorstr_test_verify_error
+~/workspace/xorstr_test strings build/msvc/Release/main.exe | grep xorstr_test_verify_error
+~/workspace/xorstr_test strings build/msvc/Debug/main.exe | grep xorstr_test_verify_error
+xorstr_test_verify_error
+```
+
+[ADVobfuscator]: https://github.com/andrivet/ADVobfuscator/blob/master/ADVobfuscator/MetaRandom.h
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+if(NOT TARGET xorstr)
+  add_library(xorstr INTERFACE IMPORTED)
+  set_target_properties(xorstr PROPERTIES
+    INTERFACE_INCLUDE_DIRECTORIES "${CMAKE_CURRENT_LIST_DIR}/include")
+endif()