This thesis concerns the security of tomorrow’s peer-to-peer real-time communication in heterogeneous networks. Because of the additional delay caused by inband handshake and the poor compatibilities of some transport protocols, it was determined that existing security protocols such as transport layer security (TLS) and datagram transport layer security (DTLS) are not suitable in such a user scenario and a new security protocol should be designed. This new security protocol is called transport encapsulation security payload (TESP). TESP not only has the advantage of low initialization delay, but also fully supports transport protocols including TCP, UDP, stream control transmission protocol (SCTP), and datagram congestion control protocol (DCCP). Also a security analysis of TESP was carried out and no security flaws were found. / Denna uppsats behandlar säkerheten för morgondagens "peer-to-peer" (P2P) realtidskommunikation i heterogena nät. På grund av den adderade fördröjning som orsakas av inbandssignalering och dålig kompabilitet hos många transportprotokoll, så kan man fastställa att existerande säkerhetsprotokoll, såsom "(Datagram) Transport Layer Security" (TLS och DTLS), inte är lämpade för denna typ av kommunikation och att ett nytt säkerhetsprotokoll bör tas fram. "Transport Encapsulation Security Payload" (TESP) är ett sådant protokoll. TESP har inte bara fördelar såsom låg uppstartsfördröjning, utan har också stöd för många transportprotokoll, t.ex. "Transport Control Protocol" (TCP), "User Datagram Protocol" (UDP), "Stream Control Transmission Protocol" (SCTP) och "Datagram Congestion Control Protocol" (DCCP). Även en säkerhetsanalys av TESP har gjorts, där inga säkerhetsproblem har kunnat påvisas.

Novel sol-gel titania-poly(dimethylsiloxane) (TiO2-PDMS) and titania-silica-N-(triethoxysilylpropyl)-O-polyethylene oxide urethane (TiO2-SiO2-TESP-PEO) coatings were developed for capillary microextraction (CME) to perform on-line preconcentration and HPLC analysis of trace impurities in aqueous samples. Due to chemical inertness of titania, effective covalent binding of a suitable organic ligand to its surface is difficult via conventional surface modification methods. In this research, sol-gel chemistry was employed to chemically bind hydroxy-terminated poly(dimethylsiloxane) (PDMS) and N-(triethoxysilylpropyl)-O-polyethylene oxide urethane (TESP-PEO) to sol-gel titania and sol-gel titania-silica network, respectively. A method is presented describing in situ preparation of the titania-based sol-gel PDMS and TESP-PEO coatings and their immobilization on the inner surface of a fused-silica microextraction capillary. To perform on-line CME-HPLC, the sol-gel TiO2-PDMS or TiO2-SiO2-TESP-PEO capillarywas installed in the HPLC injection port as an external sampling loop, and a conventionalHPLC separation column was used for the liquid chromatographic separation. The sol-gel TiO2-PDMS-coated microextraction capillary was used for on-line CME-HPLC analysis of non-polar and moderately polar analytes, and the sol-gel coatings showed excellent pH (1-13), and solvent (acetonitrile and methanol) stabilities under elevated temperatures (150 C) over analogous non-sol-gel silica-based coatings. Extraction of highly polar analytes, especially from aqueous phases is not an easy task. However, the sol-gel TiO2-SiO2-TESP-PEO-coated capillaries showed excellent capability of extracting underivatized highly polar analytes from aqueous samples. This opens the possibility to employ sol-gel titania-based polar coatings for solvent-free extraction and trace analysis of target analytes in environmental and biomedical matrices. To our knowledge, this is the first research on the use of sol-gel titania (or titania-silica)-based organic-inorganic materials as a sorbent in capillary microextraction. The newly developed sol-gel titania (or titania-silica)-based organic-inorganic hybrid extraction media provides an effective solution to coupling CME with HPLC (CME-HPLC), and this can be expected to become a powerful analytical tool in environmental investigations, proteomic research, early disease diagnosis and biomarker research. Being a combination of a highly efficient solvent free sample preconcentration technique (CME) and a powerful separation method (HPLC), CME-HPLC poses to become a key analytical tool in solving complex chemical, environmental, and biomedical problems involving complex matrices.