1. A message security processing system for Web services in which messages are exchanged between a client and a server with a SOAP-RPC format, each of the client and the server comprising: a security interface allowing information related to digital signature, encryption, and timestamp insertion to be set in a security context object for an application program to meet security requirements of the client or the server; a security handler receiving the security context object from the security interface, and performing security processing of a request message by calling security objects stored in a request queue of the security context object one by one in order or performing security processing of a response message by calling security objects stored in a response queue of the security context object one by one in order; and an XML security unit supporting an XML security function called by the security handler.