TCB – Trusted Computing Base




четверг, 26 июля 12 г.
• The trusted computing base (TCB) of a computer
               system is the set of all hardware, firmware, and/or
               software components that are critical to its security,
               in the sense that bugs or vulnerabilities occurring
               inside the TCB might jeopardize the security
               properties of the entire system.
               • By contrast, parts of a computer system outside
               the TCB must not be able to breach the security
               policy and may not get any more privileges than are
               granted to them in accordance to the security
               policy.


                                          2
четверг, 26 июля 12 г.
Trusted Computing: basic idea

                  • Addition of security hardware functionality to a
                  computer system to compensate for insecure
                  software
                  • Enables external entities to have increased
                  level of trust that the system will perform as
                  expected/specified
                  • Trusted platform = a computing platform with a
                  secure hardware component that forms a
                  security foundation for software processes
                  • Trusted Computing = computing on a Trusted
                  Platform

                                            3
четверг, 26 июля 12 г.
Trusted Hardware Examples




                                      4
четверг, 26 июля 12 г.
Characteristics of Trusted Hardware



                • Physically secure module
                • Environmental monitoring (temperature, power
                supply, structural integrity)
                • Tamper responsive
                • Optimized hardware support for cryptography
                • I/O interface




                                           5
четверг, 26 июля 12 г.
Trusted Hardware – Example
               • IBM 4764 Secure Coprocessor




                                      6
четверг, 26 июля 12 г.
IBM 4764 Application Example




                                      7
четверг, 26 июля 12 г.
TCG (Trusted Computing Group) History & Evolution

                • October 1999: TCPA formed
                – Trusted Computing Platform Alliance
                – Founders: IBM, HP, Compaq, Intel and Microsoft
                • 2001: 1st TPM specification released – Trusted
                Platform Module
                • 2002: TCPA becomes TCG
                – Trusted Computing Group
                – Not-for-profitindustrystandardsorganization
                • 2003: TPM specification adopted by TCG –
                Currently TPM specification 1.2
                • 2010: Reduced interest
                – TPM has failed to meet industry expectations
                                         8
четверг, 26 июля 12 г.
Trusted Platform Module (TPM)

             • Hardware module at heart of hardware / software
             approach to trusted computing
             • Protected memory (key storage, platform
             configuration metrics)
             • TPM chip mounted on motherboard,
             • Supports 3 basic services:
             – Secure / authenticated boot,
             – Remote attestation, allows remote party to verify
             platform state
             – Sealed storage / encryption, makes decryption
             depend on platform state

                                        9
четверг, 26 июля 12 г.
TCG supports two modes of booting


                • Secure boot
                – the platform owner can define expected (trusted)
                PCR values that are stored in special non-volatile
                Data Integrity Registers (DIR) in the TPM.
                – If a PCR value does not match the expected
                value for that stage of the boot process, TPM can
                signal a boot termination request.
                • Authenticated boot
                – does not check measured values against
                expected values – just records in PCRs


                                         10
четверг, 26 июля 12 г.
TPM – A Passive Security Enabler



     • Note that TPM is passive:
     – It doesn’t decide which software can and can’t run.
     – It provides a way to reliably report the post-boot state of the platform
     – TCG aware application or OS can be designed to not start unless
     platform is in a particular state (no malware etc)
     – TCG aware application or OS can be designed to require a TPM
     mediated online authorisation from a vendor before starting (check for
     current license etc.):
     • TCG can be used to build systems where somebody else decides
     whether software can or can’t run
     • TCG does not provide this functionality – it merely enables it




                                             11
четверг, 26 июля 12 г.
TPM Architecture


                           Processor
                                                              Endorsement K.
                          Hash engine
                                                             Storage Root Key
                         RSA Key gen.                   Non-Volatile memory




                         RSA Signing and
                           encryptyon
                                                                            PCR
                         RND generator
                                                                 Loaded Keys
                           Processor
                                                          Volatile memory




                                                   12
четверг, 26 июля 12 г.
Attestation Identity Key (AIK)
          Endorsement Key (EK)
                                                                 AIKs are used to provide platform
          The Endorsement Key (EK) is a public/private
                                                                 authentication to a service provider. This is
          key-pair. The size of the key-pair is mandated to
                                                                 also called pseudo-anonymous
          have a modulus (a.k.a. key size) of 2048 bits.
                                                                 authentication and is different from user
          The private component of the key-pair is
                                                                 authentication. Refer to the section on
          generated within the TPM and is never exposed
                                                                 attestation under usage models for an
          outside the TPM.
                                                                 illustration of how AIKs are obtained.




             Certificates:
             The Endorsement Cert contains the public key
             of the EK. The purpose of the Endorsement Cert       * RSA / AES / SHA-1 / GOST
             is to provide attestation that the particular TPM    * Import banned in:
             is genuine, i.e. that the EK is protected.
                                                                     Russia
             The Platform Cert is provided by the platform           China
             vendor and provides attestation that the security       Kazakhstan
             components of the platform are genuine.
                                                                     Belarus
             The Conformance Cert is provided by the
             platform vendor or an evaluation lab. It provides
             attestation by an accredited party as to the
             security properties of the platform.




четверг, 26 июля 12 г.

Trusted Computing Base

  • 1.
    TCB – TrustedComputing Base четверг, 26 июля 12 г.
  • 2.
    • The trustedcomputing base (TCB) of a computer system is the set of all hardware, firmware, and/or software components that are critical to its security, in the sense that bugs or vulnerabilities occurring inside the TCB might jeopardize the security properties of the entire system. • By contrast, parts of a computer system outside the TCB must not be able to breach the security policy and may not get any more privileges than are granted to them in accordance to the security policy. 2 четверг, 26 июля 12 г.
  • 3.
    Trusted Computing: basicidea • Addition of security hardware functionality to a computer system to compensate for insecure software • Enables external entities to have increased level of trust that the system will perform as expected/specified • Trusted platform = a computing platform with a secure hardware component that forms a security foundation for software processes • Trusted Computing = computing on a Trusted Platform 3 четверг, 26 июля 12 г.
  • 4.
    Trusted Hardware Examples 4 четверг, 26 июля 12 г.
  • 5.
    Characteristics of TrustedHardware • Physically secure module • Environmental monitoring (temperature, power supply, structural integrity) • Tamper responsive • Optimized hardware support for cryptography • I/O interface 5 четверг, 26 июля 12 г.
  • 6.
    Trusted Hardware –Example • IBM 4764 Secure Coprocessor 6 четверг, 26 июля 12 г.
  • 7.
    IBM 4764 ApplicationExample 7 четверг, 26 июля 12 г.
  • 8.
    TCG (Trusted ComputingGroup) History & Evolution • October 1999: TCPA formed – Trusted Computing Platform Alliance – Founders: IBM, HP, Compaq, Intel and Microsoft • 2001: 1st TPM specification released – Trusted Platform Module • 2002: TCPA becomes TCG – Trusted Computing Group – Not-for-profitindustrystandardsorganization • 2003: TPM specification adopted by TCG – Currently TPM specification 1.2 • 2010: Reduced interest – TPM has failed to meet industry expectations 8 четверг, 26 июля 12 г.
  • 9.
    Trusted Platform Module(TPM) • Hardware module at heart of hardware / software approach to trusted computing • Protected memory (key storage, platform configuration metrics) • TPM chip mounted on motherboard, • Supports 3 basic services: – Secure / authenticated boot, – Remote attestation, allows remote party to verify platform state – Sealed storage / encryption, makes decryption depend on platform state 9 четверг, 26 июля 12 г.
  • 10.
    TCG supports twomodes of booting • Secure boot – the platform owner can define expected (trusted) PCR values that are stored in special non-volatile Data Integrity Registers (DIR) in the TPM. – If a PCR value does not match the expected value for that stage of the boot process, TPM can signal a boot termination request. • Authenticated boot – does not check measured values against expected values – just records in PCRs 10 четверг, 26 июля 12 г.
  • 11.
    TPM – APassive Security Enabler • Note that TPM is passive: – It doesn’t decide which software can and can’t run. – It provides a way to reliably report the post-boot state of the platform – TCG aware application or OS can be designed to not start unless platform is in a particular state (no malware etc) – TCG aware application or OS can be designed to require a TPM mediated online authorisation from a vendor before starting (check for current license etc.): • TCG can be used to build systems where somebody else decides whether software can or can’t run • TCG does not provide this functionality – it merely enables it 11 четверг, 26 июля 12 г.
  • 12.
    TPM Architecture Processor Endorsement K. Hash engine Storage Root Key RSA Key gen. Non-Volatile memory RSA Signing and encryptyon PCR RND generator Loaded Keys Processor Volatile memory 12 четверг, 26 июля 12 г.
  • 13.
    Attestation Identity Key(AIK) Endorsement Key (EK) AIKs are used to provide platform The Endorsement Key (EK) is a public/private authentication to a service provider. This is key-pair. The size of the key-pair is mandated to also called pseudo-anonymous have a modulus (a.k.a. key size) of 2048 bits. authentication and is different from user The private component of the key-pair is authentication. Refer to the section on generated within the TPM and is never exposed attestation under usage models for an outside the TPM. illustration of how AIKs are obtained. Certificates: The Endorsement Cert contains the public key of the EK. The purpose of the Endorsement Cert * RSA / AES / SHA-1 / GOST is to provide attestation that the particular TPM * Import banned in: is genuine, i.e. that the EK is protected. Russia The Platform Cert is provided by the platform China vendor and provides attestation that the security Kazakhstan components of the platform are genuine. Belarus The Conformance Cert is provided by the platform vendor or an evaluation lab. It provides attestation by an accredited party as to the security properties of the platform. четверг, 26 июля 12 г.