ADVobfuscator
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andrivet
MetaString<1, K, Indexes<I...>> doesn't obfuscate string at compile-time but runtime
Using MetaString<1, K, Indexes<I...>>, compile with VS 2017 ver 15.7.1, disassemble and you'll find constexpr not working as supposed. As a result, the strings are obfuscated at runtime. For some unknown reason, the compiler regards the position I as a variant not a const value though it can be and indeed is produced at compile-time.
After several tries, an ugly template function fools the compiler to obfuscate string at compile-time.
template<char K, int... I>
struct MetaString<1, K, Indexes<I...>>
{
// Constructor. Evaluated at compile time. Instantiate template function **encrypt**.
constexpr ALWAYS_INLINE MetaString(const char* str)
: key_(K), buffer_ {encrypt<K+I>(str[I])...} { }
/* untouched inline const char* decrypt() */
private:
// ......
// decrypt and encrypt2 are evaluated at runtime.
constexpr char encrypt2(char c, size_t position) const { return c ^ key(position); }
constexpr char decrypt(char c, size_t position) const { return encrypt2(c, position); }
// **encrypt** will be instantiated at compile time in the constructor of this MetaString.
template<char _k>
constexpr char encrypt(char c) const { return c ^ _k; }
/* key_ and buffer_ */
};
My code definitely needs improvements for the latest versions of compilers
I had the same symptoms, so I thought this library actually does not support compile time obfuscation. Thanks for letting me know that this is a compiler dependent issue.
@MeroZemory It is dependent of the compiler you are using, its version and the compilation flags. (It was written more than 3 years...)
@andrivet Thank you for writing such a library. I was exploring instruction-level obfuscation techniques so this isn't related to what I was looking for, but it was great to get the first idea of running FSM based on predicates :)
@MeroZemory It is dependent of the compiler you are using, its version and the compilation flags. (It was written more than 3 years...)
Can you addapt it for VS 2019?
I will update this code once we have good support of C++20 in the major compilers (VS, Clang and GCC). This is currently not the case. More specifically, what I am waiting for is "string literal operator template" support.
I will update this code once we have good support of C++20 in the major compilers (VS, Clang and GCC). This is currently not the case. More specifically, what I am waiting for is "string literal operator template" support.
Thx for faster than light answer. So, VS 20 would got major updates?
Visual Studio 2022 came out today, which claims to have proper C++20 support. Is a MetaString rewrite still planned? 👼
