upload testing...

1. Towards Trusted Cloud Computing
Nuno Santos, Krishna P.Gummadi, Rodrigo Rodrigues
박승제
20111101171

2. Towards Trusted Cloud Computing?
BE305: Special Topics in Computer Systems

3. 목차
 해결하고자 하는 문제점
 가정
 배경 설명
 기술적 상세 내용
 Review Comments
BE305: Special Topics in Computer Systems

4. 해결하고자 하는 문제점
BE305: Special Topics in Computer Systems

5. Security concerns for Cloud computing
 Concerns
 Many companies can reduce cost using Cloud Computing services
 But, customers still concerned about security of data
BE305: Special Topics in Computer Systems

6. Security Cornerstones (CIA)
 Confidentiality
 To prevent unauthorized reading of information
 Integrity
 To prevent unauthorized writing of information
 Availability
 To provide access to information whenever consumers want
BE305: Special Topics in Computer Systems

7. Cloud Security Concerns
Cloud internal
administrator
Attacker
Client
BE305: Special Topics in Computer Systems

8. Vulnerability of IaaS
 Vulnerability of IaaS
 Anyone with privileged access to the host can read or manipulate
a customer’s data
 Consequently, customers cannot protect their VMs on their own
admin with root
privileges
BE305: Special Topics in Computer Systems

9. TCCP(Trusted Cloud Computing Platform)
 TCCP
 Guarantees the confidentiality and the integrity of a user’s VM
 Allows users to attest to the IaaS provider
 Determine whether the service is secure before they launch their VM
BE305: Special Topics in Computer Systems

10. 가정
BE305: Special Topics in Computer Systems

11. Eucalyptus
 What is Eucalyptus?
 an open source IaaS platform that similar to Amazon’s EC2
 manages one or more clusters whose nodes run a virtual machine monitor
 For simplicity, a single cloud manager(CM) that handles a single cluster
BE305: Special Topics in Computer Systems

12. Eucalyptus(cont.)
 From the perspective of users
 Eucalyptus provides a web service interface to launch, manage,
and terminate VMs
 A VM is launched from a virtual machine image(VMI) loaded from the CM
 Once a VM is launched, users can log in to it using normal tools
such as ssh
BE305: Special Topics in Computer Systems

13. Cloud Provider
BE305: Special Topics in Computer Systems

14. Attack model
 By enforcing a security perimeter
 the provider can prevent attacks that require physical access to the machine
 Sysadmins can login remotely to any machine with root privileges
at any point in time
BE305: Special Topics in Computer Systems

15. 배경 설명
BE305: Special Topics in Computer Systems

16. Trusted Computing
 Trusted Computing Group(TCG)
 proposed a standard for the design of the trusted platform module(TPM)
 Trusted Platform Module(TPM)
 Secure boot
 Remote attestation
BE305: Special Topics in Computer Systems

17. Remote Attestation
 Objective
 Verifier determines whether a remote system satisfies some property
 Example
 Is the remote system running the standard Ubuntu Linux v.2.6.18 kernel?
 Problem
 Can’t just ask the system, since it could lie!
BE305: Special Topics in Computer Systems

18. Remote Attestation Process
 Three Phases
 Measurement
 machine to be attested must measure its properties locally
 Attestation
 transfer measurements from machine being attested to remote machine
 Verification
 Remote machine examines measurements transferred during attestation
 decide whether they are valid and acceptable
BE305: Special Topics in Computer Systems

19. Hardware TTP for Remote attestation
 Pure software TTPs impose severe restrictions on remote attestation
assurances
 So, hardware solutions are an alternative
 Most popular: Trusted Platform Module(TPM)
BE305: Special Topics in Computer Systems

20. TPM Interconnection
BE305: Special Topics in Computer Systems

21. Trusted Platform Module
 TPM
 contains an endorsement private key that uniquely identifies the TPM
 and some cryptographic functions that cannot be modified
 Manufacturers sign the corresponding public key
 to guarantee the correctness of the chip and validity of the key
BE305: Special Topics in Computer Systems

22. How does it get measured?
Program code: BIOS Bootloader Kernel Module Module App App
SH
Hash function:
A1
Hashes: BIOS Bootloader Kernel Module Module App App
SH
A1
SH
A1 … SH
A1
H1 H2 PCR
BE305: Special Topics in Computer Systems

23. Attestation
BE305: Special Topics in Computer Systems

24. Trusted Platform
 A trusted platform like Terra implements a VMM that enforces a closed
box execution environment
 Means that a guest VM cannot be inspected or modified by a user with
full privileges over the host
 However, this is insufficient
 a sysadmin can divert a customer’s VM to a node not running the platform
 either when the VM is launched (by manipulating the CM)
 or during the VM execution (using migration)
BE305: Special Topics in Computer Systems

25. 기술적 상세 내용
BE305: Special Topics in Computer Systems

26. Trusted Cloud Computing Platform
 Trusted Cloud Computing Platform(TCCP)
 provides a closed box execution environment
 by extending the concept of trusted platform to an entire IaaS backend
 TCCP guarantees the confidentiality and the integrity of a user’s VM
BE305: Special Topics in Computer Systems

27. TCCP
 Two components
 a trusted virtual machine monitor(TVMM)
 a trusted coordinator(TC)
BE305: Special Topics in Computer Systems

28. TCCP
 External trusted entity (ETE)
 hosts the TC
 securely updates the information provided to the TC
 set of nodes deployed within the IaaS, configurations...
BE305: Special Topics in Computer Systems

29. Protocols of TCCP
 Our proposal
 the TCCP protocols to secure the VM launch and migration
Message exchange during VM migrate
Message exchange during node registration
Message exchange during VM launch
BE305: Special Topics in Computer Systems

30. Basic Communication Scenario
Encryption Key Decryption Key
plaintext ciphertext plaintext
Encrypt Decrypt
Enemy or
Eavesdropper
BE305: Special Topics in Computer Systems

31. Symmetric-key Vs. Public-key
 Symmetric key
 Same key for encryption as for decryption
 Public key (asymmetric)
 require two separate keys, one to lock, one to unlock
BE305: Special Topics in Computer Systems

32. Notation
 <Kp, KP>
 private-public keys of an asymmetric cryptography keypair
 {y}Kx
 the data y is encrypted with key Kx
 EKx
 endorsement keys
 TKx
 trusted keys
 Kx
 session keys
 nx
 Nonce, unique numbers generated by x
BE305: Special Topics in Computer Systems

33. Node management
 Trusted Coordinator(TC)
 dynamically manages the set of trusted nodes by maintaining a directory
 Directory
 Each node id
P
 the public endorsement key EK N
 expected measurement list MLN
 TC available to the public
P P
TKTC MLTC EKTC
BE305: Special Topics in Computer Systems

34. Node registration
 To be trusted, a node must register with the TC
1. nN to avoid an impersonation of the TC by an attacker
1.
N TC
BE305: Special Topics in Computer Systems

35. Node registration
 To be trusted, a node must register with the TC
to guarantee the authenticity of the TC
1. nN
2. {MLTC , n N } EK p , nTC
TC
TC also attests to N
if this matches the expected configuration, it
means the TC is trusted
1.
2.
N TC
BE305: Special Topics in Computer Systems

36. Node registration
 To be trusted, a node must register with the TC
1. nN make private-public key and send
its public key to the TC
2. {MLTC , n N } EK p , nTC
TC
3. {{ MLN , nTC } EK p ,TK N } TK P
P
N TC
1.
2.
N 3.
TC
BE305: Special Topics in Computer Systems

37. Node registration
 To be trusted, a node must register with the TC
If both peers mutually attest successfully,
1. nN P
the TC adds TK N to its node database
2. {MLTC , n N } EK p , nTC
TC
3. {{ MLN , nTC } EK p ,TK N } TK P
P
N TC
4. {accepted } TK P
N
1.
2.
N 3.
TC
4.
BE305: Special Topics in Computer Systems

38. Our protocol
 VM launch protocol
 VM migration protocol
 the initial VM state α
 contains the VM image(VMI)
 the user’s public key(used for ssh login)
BE305: Special Topics in Computer Systems

39. VM launch
1. {α, # α} K VM , { nU , KVM } TK P
TC
user generates a session key KVM
1.
α
CM
U
N TC
BE305: Special Topics in Computer Systems

40. VM launch
1. {α, # α} K , { nU , KVM } TK
VM
P
TC
2. {{{ nU , KVM } TK , n N } TK }, N } TK
P
TC
p
N
P
TC
the TC can verify whether N is trusted
1.
α
CM
U
2.
N TC
BE305: Special Topics in Computer Systems

41. VM launch
1. {α, # α} K , { nU , KVM } TK
VM
P
TC
N is now available decrypt α,
2. {{{ nU , KVM } TK , n N } TK }, N } TK
P
TC
p
N
P
TC
and boot the VM
3. {{ n N , nU , KVM } TK } TK
p
N
p
TC
1.
α
CM
U
2.
N TC
3.
BE305: Special Topics in Computer Systems

42. VM launch
1. {α, # α} K , { nU , KVM } TK
VM
P
TC
2. {{{ nU , KVM } TK , n N } TK }, N } TK
P
TC
p
N
P
TC
3. {{ n N , nU , KVM } TK } TK
p
N
p
TC
4. {nU , N} K VM
1.
α
CM 4.
U
2.
N TC
3.
BE305: Special Topics in Computer Systems

43. VM migration
1. {{ Nd , n s } TK , N s } TK
p
N
P
TC
2. {{ ns 1,TKN } TK } TK
P
P p
d Ns TC CM
Nd
1 & 2, Ns asks TC to check
whether Nd is trusted
VM
1.
Ns TC
2.
BE305: Special Topics in Computer Systems

44. VM migration
1. {{ Nd , n s } TK , N s } TK
p
N
P
TC
2. {{ ns 1,TKN } TK } TK
P
P p
d Ns TC CM
3. Nd
3. {{ K S , ns 2} TK , Ns } TK
p P
Ns Nd
Session key Ks that will be used
to secure the transfer of the VM
state VM
1.
Ns TC
2.
BE305: Special Topics in Computer Systems

45. VM migration
1. {{ Nd , n s } TK , N s } TK
p
N
P
TC
2. {{ ns 1,TKN } TK } TK
P
P p
d Ns TC CM
3. Nd
3. {{ K S , ns 2} TK , Ns } TK
p P
Ns Nd
4. {{ Ns , nd } TK , Nd } TK
p P
Nd TC
5. {{ nd ,TKN } }
P 4. 5.
P p
TKsTK Nd TC
VM
1.
Ns TC
2.
before accepting the key,
Nd first verifies that Ns is trusted(4,5)
BE305: Special Topics in Computer Systems

46. VM migration
1. {{ Nd , n s } TK , N s } TK
p
N
P
TC
2. {{ ns 1,TKN } TK } TK
P
P p
d Ns TC CM
3. Nd
3. {{ K S , ns 2} TK , Ns } TK
p P
Ns Nd
4. {{ Ns , nd } TK , Nd } TK
p P
Nd TC
6.
5. {{ nd ,TKN } }
P 4. 5.
P p
TKsTK Nd TC 7.
VM
6. {n }
d KS Ns 1.
TC
2.
7. {VMid , # VMid } KS
BE305: Special Topics in Computer Systems

47. Review Comments
BE305: Special Topics in Computer Systems

48. Review Comments
 표기법이 이해하는 데 힘들었다.
 소문자, 대문자로 구분 표기법
 군더더기 없는 논문
 이 프로토콜은 정말로 효율적인가?
BE305: Special Topics in Computer Systems

49. BE305: Special Topics in Computer Systems