diff --git a/server/function_map.cc b/server/function_map.cc
index b7be9ba..cf5f602 100644
--- a/server/function_map.cc
+++ b/server/function_map.cc
@@ -1,9 +1,13 @@
 #include "function_map.hh"
+#include "c_string.hh"
 
 
 template<>
 js::Value Type2String<std::string>::get()  { return "String"; }
 
+template<>
+js::Value Type2String<c_string>::get()  { return "String"; }
+
 template<>
 js::Value Type2String<const char*>::get()  { return "String"; }
 
diff --git a/server/function_map.hh b/server/function_map.hh
index 0086027..e2dc6ea 100644
--- a/server/function_map.hh
+++ b/server/function_map.hh
@@ -1,14 +1,183 @@
 #ifndef FUNCTION_MAP_HH
 #define FUNCTION_MAP_HH
 
+#include "json_spirit/json_spirit_value.h"
+#include "json_spirit/json_spirit_writer.h"
 
-#include "inout.hh"
-#include "c_string.hh"
+#include "context.hh"
 #include <type_traits>
-#include "json_spirit/json_spirit_writer.h"
 
 // Just for debugging:
 #include <iostream>
+#include <pEp/message_api.h>
+
+
+namespace js = json_spirit;
+
+template<class T, bool NeedInput> struct In;
+template<class T, bool NeedInput> struct Out;
+
+// "params" and "position" might be used to fetch additional parameters from the array.
+template<class T>
+T from_json(const js::Value& v);
+
+
+template<class T>
+js::Value to_json(const T& t);
+
+
+// helper classes to specify in- and out-parameters
+template<class T, bool NeedInput=true>
+struct In
+{
+	typedef T c_type; // the according type in C function parameter
+	enum { is_output = false, need_input = NeedInput };
+	
+	explicit In(const T& t) : value(t) {}
+	~In();
+	
+	In(const In<T,NeedInput>& other) = delete;
+	In(In<T,NeedInput>&& victim) = delete;
+	In<T,NeedInput>& operator=(const In<T,NeedInput>&) = delete;
+	
+	// default implementation:
+	In(const js::Value& v, Context*)
+	: In( from_json<T>(v) )
+	{ }
+	
+	js::Value to_json() const
+	{
+		return ::to_json<T>(value);
+	}
+	
+	c_type get_value() const { return value; }
+	
+	T value;
+};
+
+
+// to call functions that operate directly on the JSON data type
+template<class T, bool NeedInput=true>
+struct InRaw
+{
+	typedef js::Value c_type; // do not unwrap JSON data type
+	enum { is_output = false, need_input = NeedInput };
+	
+	explicit InRaw(const js::Value& t) : value(t) {}
+	~InRaw() = default;
+	
+	InRaw(const InRaw<T,NeedInput>& other) = delete;
+	InRaw(InRaw<T,NeedInput>&& victim) = delete;
+	InRaw<T,NeedInput>& operator=(const InRaw<T,NeedInput>&) = delete;
+	
+	// default implementation:
+	InRaw(const js::Value& v, Context*)
+	: InRaw(v)
+	{ }
+
+	js::Value to_json() const
+	{
+		throw std::logic_error( std::string(typeid(T).name()) + " is not for output!" );
+	}
+	
+	c_type get_value() const { return value; }
+	
+	js::Value value;
+};
+
+
+// helper classes to specify in- and out-parameters
+template<class T, bool NeedInput=true>
+struct InOut : public In<T,NeedInput>
+{
+	typedef In<T,NeedInput> Base;
+	enum { is_output = true, need_input = NeedInput };
+
+	explicit InOut(const T& t) : Base(t) {}
+	~InOut() = default;
+	
+	InOut<T,NeedInput>& operator=(const InOut<T,NeedInput>&) = delete;
+	
+	// default implementation:
+	InOut(const js::Value& v, Context*)
+	: Base( from_json<T>(v) )
+	{ }
+	
+	js::Value to_json() const
+	{
+		return ::to_json<T>(Base::value);
+	}
+};
+
+
+template<class T, bool NeedInput = true>
+struct Out
+{
+	typedef T* c_type; // the according type in C function parameter
+	enum { is_output = true, need_input = NeedInput }; // if need_input=false it would no longer consume an element in the input parameter array.
+	
+	Out() : value{ new T{} }
+	{
+		if(typeid(T)==typeid(_message*))
+		{
+			std::cerr << "|$ Out<message*>(): this=" << *this << "\n";
+		}
+	}
+	
+	~Out();
+	
+	Out(const Out<T,NeedInput>& other) = delete;
+	Out(Out<T,NeedInput>&& victim) = delete;
+	
+	// just to be sure they are not implicitly defined:
+	Out<T,NeedInput>& operator=(const Out<T,NeedInput>& other) = delete;
+	Out<T,NeedInput>& operator=(Out<T,NeedInput>&& victim) = delete;
+	
+	Out(const js::Value& v, Context*)
+	: Out()
+	{ }
+	
+	js::Value to_json() const
+	{
+		return ::to_json<T>(*value);
+	}
+	
+	c_type get_value() const { return value; }
+	
+	T* value = nullptr;
+	
+	friend
+	std::ostream& operator<<(std::ostream& o, const Out<T,NeedInput>& out)
+	{
+		o << (const void*)&out;
+		
+// the if() was added to avoid crashes on memory corruptuon. But clang++ warns, that this check is always true on "well-formed" programs, and he is right. In an ideal world there are no memory corruptions. ;-(
+//		if(&out)
+		{
+			o << ", value=" << (const void*)out.value;
+			if(out.value)
+			{
+				o << ", *value=" << *(out.value);
+			}
+		}
+		
+		return o;
+	}
+	
+};
+
+
+template<class T, bool NeedInput>
+js::Value to_json(const Out<T,NeedInput>& o)
+{
+	return ::to_json(*o.value);
+}
+
+template<class T, bool NeedInput>
+js::Value to_json(const InOut<T,NeedInput>& o)
+{
+	return ::to_json(o.value);
+}
 
 
 // heloer class for generic calls:
diff --git a/server/inout.cc b/server/inout.cc
index 3195ed6..ecb4643 100644
--- a/server/inout.cc
+++ b/server/inout.cc
@@ -1,25 +1,6 @@
 #include "inout.hh"
 #include <stdexcept>
-
-#include <cstring> // for memcpy()
-
-
-namespace
-{
-	char* make_c_string(const std::string& src)
-	{
-		char* dest = (char*)malloc(src.size() + 1);
-		memcpy(dest, src.c_str(), src.size() + 1 );
-		return dest;
-	}
-}
-
-
-template<>
-In<char const*>::~In()
-{
-	if(value) free(const_cast<char*>(value));
-}
+#include <pEp/pEpEngine.h>
 
 
 #define SIMPLE_TYPE(TYPE)     \
@@ -53,7 +34,7 @@ Out<char const*>::~Out()
 {
 	if(value)
 	{
-		free(const_cast<char*>(*value));
+		pEp_free(const_cast<char*>(*value));
 	}
 	delete value;
 }
@@ -64,7 +45,7 @@ Out<char*>::~Out()
 {
 	if(value)
 	{
-		free(*value);
+		pEp_free(*value);
 		*value = nullptr;
 	}
 	delete value;
@@ -138,18 +119,6 @@ std::string from_json<std::string>(const js::Value& v)
 }
 
 
-template<>
-char* from_json<char*>(const js::Value& v)
-{
-	return make_c_string( v.get_str() );
-}
-
-template<>
-const char* from_json<const char*>(const js::Value& v)
-{
-	return make_c_string( v.get_str() );
-}
-
 
 template<class T>
 js::Value to_json(const T& t)
diff --git a/server/json-adapter.cc b/server/json-adapter.cc
index 496258a..1fb392e 100644
--- a/server/json-adapter.cc
+++ b/server/json-adapter.cc
@@ -205,17 +205,17 @@ PEP_STATUS MIME_decrypt_message_ex(
 const FunctionMap functions = {
 		// from message_api.h
 		FP( "Message API", new Separator ),
-		FP( "MIME_encrypt_message", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<const char*>, In<size_t>, In<stringlist_t*>,
+		FP( "MIME_encrypt_message", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<c_string>, In<size_t>, In<stringlist_t*>,
 			Out<char*>, In<PEP_enc_format>, In<PEP_encrypt_flags_t>>( &MIME_encrypt_message ) ),
-		FP( "MIME_encrypt_message_for_self", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<pEp_identity*>, In<const char*>, In<size_t>,
+		FP( "MIME_encrypt_message_for_self", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<pEp_identity*>, In<c_string>, In<size_t>,
 			Out<char*>, In<PEP_enc_format>, In<PEP_encrypt_flags_t>>( &MIME_encrypt_message_for_self ) ),
-		FP( "MIME_decrypt_message", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<const char*>, In<size_t>,
+		FP( "MIME_decrypt_message", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<c_string>, In<size_t>,
 			Out<char*>, Out<stringlist_t*>, Out<PEP_rating>, Out<PEP_decrypt_flags_t>>( &MIME_decrypt_message ) ),
 		
 		// HACK: because "auto sessions" are per TCP connections, add a parameter to set passive_mode each time again
-		FP( "MIME_encrypt_message_ex", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<const char*>, In<size_t>, In<stringlist_t*>, In<bool>,
+		FP( "MIME_encrypt_message_ex", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<c_string>, In<size_t>, In<stringlist_t*>, In<bool>,
 			Out<char*>, In<PEP_enc_format>, In<PEP_encrypt_flags_t>>( &MIME_encrypt_message_ex ) ),
-		FP( "MIME_decrypt_message_ex", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<const char*>, In<size_t>, In<bool>,
+		FP( "MIME_decrypt_message_ex", new Func<PEP_STATUS, In<PEP_SESSION, false>, In<c_string>, In<size_t>, In<bool>,
 			Out<char*>, Out<stringlist_t*>, Out<PEP_rating>, Out<PEP_decrypt_flags_t>>( &MIME_decrypt_message_ex ) ),
 		
 		FP( "startKeySync", new Func<void, In<JsonAdapter*, false>>( &JsonAdapter::startSync) ),
@@ -232,7 +232,7 @@ const FunctionMap functions = {
 		FP( "get_gpg_path",    new Func<PEP_STATUS, Out<const char*>>(&get_gpg_path) ),
 		
 		FP( "pEp Engine Core API", new Separator),
-		FP( "log_event",  new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<const char*>, In<const char*>, In<const char*>>( &log_event) ),
+		FP( "log_event",  new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<c_string>, In<c_string>, In<c_string>>( &log_event) ),
 		FP( "get_trustwords", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const pEp_identity*>, In<const pEp_identity*>, In<Language>, Out<char*>, Out<size_t>, In<bool>>( &get_trustwords) ),
 		FP( "get_languagelist", new Func<PEP_STATUS, In<PEP_SESSION,false>, Out<char*>>( &get_languagelist) ),
 		FP( "get_phrase"      , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<Language>, In<int>, Out<char*>> ( &get_phrase) ),
@@ -241,9 +241,9 @@ const FunctionMap functions = {
 		FP( "config_unencrypted_subject", new Func<void, In<PEP_SESSION,false>, In<bool>>( &config_unencrypted_subject) ),
 		
 		FP( "Identity Management API", new Separator),
-		FP( "get_identity"       , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<const char*>, Out<pEp_identity*>>( &get_identity) ),
+		FP( "get_identity"       , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<c_string>, Out<pEp_identity*>>( &get_identity) ),
 		FP( "set_identity"       , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<pEp_identity*>> ( &set_identity) ),
-		FP( "mark_as_comprimized", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>> ( &mark_as_compromized) ),
+		FP( "mark_as_comprimized", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>> ( &mark_as_compromized) ),
 		FP( "identity_rating"    , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<pEp_identity*>, Out<PEP_rating>>( &identity_rating) ),
 		FP( "outgoing_message_rating", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<message*>, Out<PEP_rating>>( &outgoing_message_rating) ),
 		FP( "set_identity_flags"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, InOut<pEp_identity*>, In<identity_flags_t>>( &set_identity_flags) ),
@@ -251,12 +251,12 @@ const FunctionMap functions = {
 		
 		FP( "Low level Key Management API", new Separator),
 		FP( "generate_keypair", new Func<PEP_STATUS, In<PEP_SESSION,false>, InOut<pEp_identity*>> ( &generate_keypair) ),
-		FP( "delete_keypair", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>> ( &delete_keypair) ),
-		FP( "import_key"    , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<std::size_t>, Out<identity_list*>> ( &import_key) ),
-		FP( "export_key"    , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<char*>, Out<std::size_t>> ( &export_key) ),
-		FP( "find_keys"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<stringlist_t*>> ( &find_keys) ),
+		FP( "delete_keypair", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>> ( &delete_keypair) ),
+		FP( "import_key"    , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<std::size_t>, Out<identity_list*>> ( &import_key) ),
+		FP( "export_key"    , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<char*>, Out<std::size_t>> ( &export_key) ),
+		FP( "find_keys"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<stringlist_t*>> ( &find_keys) ),
 		FP( "get_trust"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, InOut<pEp_identity*>> ( &get_trust) ),
-		FP( "own_key_is_listed", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<bool>> ( &own_key_is_listed) ),
+		FP( "own_key_is_listed", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<bool>> ( &own_key_is_listed) ),
 		FP( "own_identities_retrieve", new Func<PEP_STATUS, In<PEP_SESSION,false>, Out<identity_list*>>( &own_identities_retrieve ) ),
 		FP( "undo_last_mitrust", new Func<PEP_STATUS, In<PEP_SESSION,false>>( &undo_last_mistrust ) ),
 		
@@ -267,18 +267,18 @@ const FunctionMap functions = {
 		FP( "key_mistrusted",     new Func<PEP_STATUS, In<PEP_SESSION,false>, In<pEp_identity*>>( &key_mistrusted) ),
 		FP( "key_reset_trust",    new Func<PEP_STATUS, In<PEP_SESSION,false>, In<pEp_identity*>>( &key_reset_trust) ),
 		
-		FP( "least_trust"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<PEP_comm_type>> ( &least_trust) ),
-		FP( "get_key_rating", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<PEP_comm_type>> ( &get_key_rating) ),
-		FP( "renew_key"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<const timestamp*>> ( &renew_key) ),
-		FP( "revoke"        , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<const char*>> ( &revoke_key) ),
-		FP( "key_expired"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, In<time_t>, Out<bool>> ( &key_expired) ),
+		FP( "least_trust"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<PEP_comm_type>> ( &least_trust) ),
+		FP( "get_key_rating", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<PEP_comm_type>> ( &get_key_rating) ),
+		FP( "renew_key"     , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<const timestamp*>> ( &renew_key) ),
+		FP( "revoke"        , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<c_string>> ( &revoke_key) ),
+		FP( "key_expired"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, In<time_t>, Out<bool>> ( &key_expired) ),
 		
 		FP( "from blacklist.h & OpenPGP_compat.h", new Separator),
-		FP( "blacklist_add"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>> ( &blacklist_add) ),
-		FP( "blacklist_delete", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>> ( &blacklist_delete) ),
-		FP( "blacklist_is_listed", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<bool>> ( &blacklist_is_listed) ),
+		FP( "blacklist_add"   , new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>> ( &blacklist_add) ),
+		FP( "blacklist_delete", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>> ( &blacklist_delete) ),
+		FP( "blacklist_is_listed", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<bool>> ( &blacklist_is_listed) ),
 		FP( "blacklist_retrieve" , new Func<PEP_STATUS, In<PEP_SESSION,false>, Out<stringlist_t*>> ( &blacklist_retrieve) ),
-		FP( "OpenPGP_list_keyinfo", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<const char*>, Out<stringpair_list_t*>> ( &OpenPGP_list_keyinfo) ),
+		FP( "OpenPGP_list_keyinfo", new Func<PEP_STATUS, In<PEP_SESSION,false>, In<c_string>, Out<stringpair_list_t*>> ( &OpenPGP_list_keyinfo) ),
 		
 		FP( "Event Listener & Results", new Separator ),
 		FP( "registerEventListener"  , new Func<PEP_STATUS, In<Context*, false>, In<std::string>, In<unsigned>, In<std::string>> ( &registerEventListener) ),