Bachelors Thesis: A Certification Service for future Home Networks - PowerPoint PPT Presentation

Lehrstuhl Netzarchitekturen und Netzdienste Institut für Informatik TU München Bachelor‘s Thesis: A Certification Service for future Home Networks based on Trusted Computing Technology Announcement: Prof. Georg Carle Advisor: Holger Kinkelin Student: Simon Mittelberger Lehrstuhl für Netzarchitekturen und Netzdienste TU München

Agenda  Existing Approach  Security Analysis / Motivation  Key Requirements  Approach  Evaluation  Related Work  Conclusion & Future Work Bachelor Thesis SS 2009 2

AutHoNe’s PKI Bachelor Thesis SS 2009 3

Trust Relationship Bachelor Thesis SS 2009 4

Trust Relationship Bachelor Thesis SS 2009 5

Security Analysis / Motivation Home Key and Device Key are in Danger  Identity Theft  Treacherous Home  Treacherous Device Bachelor Thesis SS 2009 6

Trust Relationship Bachelor Thesis SS 2009 7

Identity Theft Bachelor Thesis SS 2009 8

Identity Theft Bachelor Thesis SS 2009 9

Identity Theft Bachelor Thesis SS 2009 10

Identity Theft Bachelor Thesis SS 2009 11

Treacherous Device Bachelor Thesis SS 2009 12

Treacherous Device Bachelor Thesis SS 2009 13

Key Requirements  R1 Protection of the Private Key  Home Key  Device Key  R2 Prove Protection to other Entities  R3 Backup of the Home Key Bachelor Thesis SS 2009 14

Approach Use a Trusted Platform Module (TPM) for Management of the Key  Private part of a Key managed through a TPM is never readable from the outside => R1 (Protection)  Protection and type of protection is provable => R2 (Proof)  Certain Migration Schemes allow a Migration of a Key to another TPM => R3 (Backup) Bachelor Thesis SS 2009 15

Important Keys in a TPM  Endorsement Key (EK): unique for every TPM, can only sign internal data, not migratable  Attestation Identity Key (AIK): derives from EK, can only sign internal data, not migratable  Signing Key (SK): only signing operations of internal and external data, migratable/not migratable  Legacy Key (LK): signing and encryption operations of internal and external data, migratable/not migratable Bachelor Thesis SS 2009 16

Current AutHoNe PKI Bachelor Thesis SS 2009 17

AutHoNe TPM Integration Bachelor Thesis SS 2009 18

TPM Credentials Bachelor Thesis SS 2009 19

TPM Credentials - Migratability Bachelor Thesis SS 2009 20

Evaluation No TPM Protection Migratable Key Non Migratable Key Usability - Backup of Key - Identity Theft Possible - Treacherous Device Attacks - Treacherous Home Bachelor Thesis SS 2009 21

Evaluation No TPM Protection Migratable Key Non Migratable Key Usability - Backup of Key - Backup of Key - Identity Theft Possible - Treacherous Device - Treacherous Device Attacks - Treacherous Home - Treacherous Home Bachelor Thesis SS 2009 22

Evaluation No TPM Protection Migratable Key Non Migratable Key Usability - Backup of Key - Backup of Key - No Backup of Key - Identity Theft Possible - Treacherous Device - Treacherous Device Attacks - Treacherous Home - Treacherous Home - Treacherous Home Bachelor Thesis SS 2009 23

Treacherous Home Bachelor Thesis SS 2009 24

Evaluation  Trade off between usability and security caused by migratability  Migratable Key = weak security, strong usability  Non Migratable Key = strong security, weak usability No TPM Protection Migratable Key Non Migratable Key Usability - Backup of Key - Backup of Key - No Backup of Key - Identity Theft Possible - Treacherous Device - Treacherous Device Attacks - Treacherous Home - Treacherous Home - Treacherous Home Bachelor Thesis SS 2009 25

Performance  Performance of the Device Registration Process Bachelor Thesis SS 2009 26

Performance  Performance of the Device Registration Process Device Device with TPM Create CSR 0.697s 1.169s Process CSR through HCS 1.261s 1.427s Process CSR through Device 0.555s 0.815s *Times without loading time and network transmissions Bachelor Thesis SS 2009 27

Technical Limitations  Infrastructure is not completed  PCA does not exist yet (only proof of concept)  Not all TPM Manufacturers ship the EK Certificates  Other Certificates unavailable  Migration Infrastructure is incomplete Bachelor Thesis SS 2009 28

Related Work: SKAE Bachelor Thesis SS 2009 29

SKAE vs. this Approach  AIK signs Key directly => no migratability  No outstanding benefit, reached through SKAE  CA PCA: central entities involved in the process => overhead Bachelor Thesis SS 2009 30

Conclusion  Main Goal achieved: Private Home Key is protected through a TPM  Design is dynamic and applicable also on a Device  Trade off: usability vs. security <=> migratability vs. non migratability  Trade off at users side Bachelor Thesis SS 2009 31

Future Work  Infrastructure has to be completed  Exploit advantages of provable TPM protection  Trust Level leads to Access Level Bachelor Thesis SS 2009 32

Questions? Bachelor Thesis SS 2009 33

Literature  Thomas Müller – Trusted Computing Systeme  Trusted Computing Group – TPM Specification Part 1, Part 2, Part 3 http://www.trustedcomputinggroup.org/resources/ tpm_specification_version_12_revision_103_part_1__3/  TCG Infrastructure Workgroup – Subject Key Attestation Evidence http://www.trustedcomputinggroup.org/files/resource_files/ 876A7F79-1D09-3519-AD321B21144AE93C/ IWG_SKAE_Extension_1-00.pdf  IAIK TU Graz - Trusted Computing for the JAVA Platform http://trustedjava.sourceforge.net/  Simon Mittelberger – A Certification Service for future Home Networks based on Trusted Computing Technology Bachelor Thesis SS 2009 34