crypt.cpp

#pragma comment(lib, "crypt32.lib")

#include <cstddef>
#include <string>
#include <windows.h>
#include <Wincrypt.h>

bool encrypt(const std::string& key, const std::string& plain, void* crypt, size_t* crypt_len )
{
    DATA_BLOB key_bolb;
    key_bolb.pbData = (BYTE*)key.c_str();
    key_bolb.cbData = key.length()+1;

    DATA_BLOB plain_bolb;
    plain_bolb.pbData = (BYTE*)plain.c_str();
    plain_bolb.cbData = plain.length()+1;

    DATA_BLOB crypt_bolb; // must LocalFree

    BOOL result
     = CryptProtectData(
        &plain_bolb,
        L"",
        &key_bolb,
        NULL,
        NULL,
        0,
        &crypt_bolb);

    if(result)
    {
        *crypt_len = (size_t)crypt_bolb.cbData;
        if(crypt != NULL )
            ::memcpy(crypt, crypt_bolb.pbData, *crypt_len);
    }
    LocalFree( crypt_bolb.pbData );

    if(result)
        return true;
    else
        return false;
}

bool decrypt(const std::string& key, const void* crypt, const size_t crypt_len, std::string& plain )
{
    DATA_BLOB key_bolb;
    key_bolb.pbData = (BYTE*)key.c_str();
    key_bolb.cbData = key.length()+1;

    DATA_BLOB crypt_bolb;
    crypt_bolb.pbData = reinterpret_cast<BYTE*>(const_cast<void*>(crypt));
    crypt_bolb.cbData = crypt_len;

    DATA_BLOB plain_bolb; // must LocalFree
    LPWSTR* desc = NULL;  // must LocalFree

    BOOL result
    = CryptUnprotectData(
        &crypt_bolb,
        desc,
        &key_bolb,
        NULL,
        NULL,
        0,
        &plain_bolb);

    if(result)
    {
        plain = (char*)plain_bolb.pbData;
    }
    LocalFree( plain_bolb.pbData );
    LocalFree( desc );

    if(result)
        return true;
    else
        return false;
}