gn (using XML Signature) all or part of a SOAP message and passes the signature in the SOAP header. It provides a mechanism that allows one to encrypt (using XML Encryption) all or part of a SOAP message. It also provides a way to pass information in a SOAP header about the encryption keys needed to decrypt the message or verify the digi- tal signature. And it allows trust assertions about the SOAP message to be passed in the SOAP header as well. WS-security module is implemented as standard security mechanisms for the protection of SOAP messages. WS-security module is a very important module of the security object, because it is used for protection: Communication with STS server-STS server Communication with the proposed municipality's SOA-based platform Protection of corresponding SOAP message with m-residence certificate In this way, the WS-security module communicates with STS module of the security object as well as with Business functionalities object. 11.4.3.5 STS Module The STS module is responsible for communication with the STS server in order to receive a SAML assertion (token) that will be used afterwards to enable access to the proposed online m-residence certificate services by the client. The client first sends a RST message to the STS server by using a SAML protocol. Security is done by using WS-security. After successful authentica- tion of the user based on the client's X.509v3 digital certificate, the STS server issues a SAML token to the user which is digitally signed by the STS server. This token is securely communicated to the end user by using the WS-security mechanisms. After successful checking of WS-security mechanisms (decryption and verifica- tion of digital signature on the level of SOAP message), the end user prepares a message with the request of m-residence certificate service. This message consists of the SAML token and is additionally secured by WS-security mechanisms. The actual URL of the municipality's online services is found in the SAML token. After successful decryption and