Crosswalk 7

Hi all) I am want send binary data from file to javascript with mechanism crosswalk extension. For this yesterday i used SendSyncReply(encoded.c_str()); function .But char* string in C  have /00 char symbol for end of data.Therefore my binary data trimmed. Today i am use encode and decode to base64 in my crosswalk extension.Is there an easier and less costly way for send binary data to js?