#include <boost/uuid/sha1.hpp>
std::string Cryptography::GetHash(void const* buffer, std::size_t len)
{
    std::stringstream ss;
    boost::uuids::detail::sha1 sha;
    sha.process_bytes(buffer, len);
    unsigned int digest[5];      //摘要的返回值
    sha.get_digest(digest);
    for (int i = 0; i < 5; ++i)
        ss << std::hex << digest[i];

    return ss.str();
}