+extern int base64_decode (std::string const & in, unsigned char* out, int out_length);
+extern boost::optional<boost::filesystem::path> relative_to_root (boost::filesystem::path root, boost::filesystem::path file);
+extern FILE * fopen_boost (boost::filesystem::path, std::string);
+extern std::string file_to_string (boost::filesystem::path, uintmax_t max_length = 65536);
+extern std::string private_key_fingerprint (std::string key);
+extern xmlpp::Node* find_child (xmlpp::Node const * node, std::string name);
+