Today's forecast: cloudy with some rain Towards secure & reliable Cloud Computing

Transcription

1 Department of Computer Science Institute of Systems Architecture Chair of Computer Networks Today's forecast: cloudy with some rain Towards secure & reliable Cloud Computing Dr.-Ing. Stephan Groß DESY Computing Seminar Hamburg, 16 January 2012

2 Faculty of Computer Science Chair for Computer Networks 26 professors 2300 students 9 post-docs 31 total staff and PhD candidates #2

3 Research Topics Applications Peer-to-Peer Internet Devices Access Technologies Large-Scale Computing #3

4 Flexible Service Architectures for Cloud Computing Mobile and Ubiquitous Computing Internet Information Retrieval Real-Time Collaboration Energy Lab Network Planing and Security Service & Cloud Computing EU-funded research group: 10/2010 9/2013 Dr.-Ing. Josef Spillner Dipl.-Medieninf. Marc Mosch Dr.-Ing. Stephan Groß Dipl.-Medieninf. Yvonne Thoß Dr.-Ing. Anja Strunk Exploring Cyber Physical Systems #4

5 Outline Cloud Computing What is it all about? Problems? π-box: Building your personal secure cloud Secure Cloud Storage Conclusion & Future Work #5

6 The shape of a cloud is in the eye of the beholder. #6

7 Definition Cloud Computing is On-demand self service Rapid elasticity the on-demand and pay-per-use application of virtualised IT services over the Internet. Broadband network access Measured service Resource pooling Adopted from the NIST Definition of Cloud Computing [MeGr2011] #7

8 What is it all about? Problems? π-box: Building your personal secure cloud Secure Cloud Storage Conclusion & Future Work #8

9 FlexCloud Objectives Unified Cloud Prevent Vendor-Lock-in + Integration of existing IT Secure Cloud Ensure data privacy and security Managed Cloud Keep the user in command Efficient Cloud Adapt to user preferences and cloud's vital signs #9

10 FlexCloud research topics Cloud Adaption and Optimization Strategies for the compensation of SLA violations Strategies for minimisation of energy consumption Mechanisms for the visualisation of comples Cloud Monitoring data Cloud Surveillance and Incident Detection Specification of monitoring targets and SLA violations Models for the proactive recognition of SLA violations and the evaluation of Cloud s energy efficiency Mechanisms for reliable distributed Monitoring Fine-grained Service Level Agreements Methods to determine fine-grained nonfunctional properties of Cloud Services Identification of assets and corresponding requirements Deduction of monitoring targets from SLAs Dynamic Provider Selection and Cloud Setup Flexible distribution mechanisms for Cloud Platforms Strategies for the performance optimization of Cloud Applications Reputation consideration to improve reliability and trustworthiness # 10

11 What is it all about? Problems? π -Box: Building your personal secure cloud Secure Cloud Storage Conclusion & Future Work # 11

12 FlexCloud's approach Subsume all end devices within a Personal Secure Cloud (π-cloud) controlled by the π-box. π-cloud π-box # 12

13 FlexCloud's approach π-box distinguishes between public and sensitive data and enforces security mechanisms for the later. π-cloud π-box # 13

14 Transparent encryption Analysis of structured, unstructured data and context information π-cloud PKI PKI?? # 14

15 Building a cloud of clouds by connecting several π-clouds. Propagation of data and services within one π-cloud and to others. π-cloud π-box # 15

16 π-box architecture User Interface / GUI Service execution wrt. to security and other non-functional requirements. Virtualisation Service Service Controller Controller Data Data Controller Controller Data storage & distribution wrt. to security and other non-functional requirements. Infrastructure management Resource ResourceManager Manager Peer2Peer Network private resources (trustworthy) public resources (not necessarily trustworthy) # 16

17 π-box deployment models π-box # 17

18 What is it all about? Problems? π-box: Building your personal secure cloud Secure Cloud Storage Conclusion & Future Work # 18

19 Increasing availability: From RAID to RAIC RAIC: Redundant Array of Independent Clouds RAID: Redundant Array of Independent Disks # 19

20 Secure Cloud Storage Integrator for Enterprises (SecCSIE) System Architecture [SGS11] # 20

21 Uploading files (1/5) # 21

22 Shared Folder Technology: FUSE (Filesystem in Userspace) CIFS/SMB network share on proxy file server Unified user interface for arbitrary cloud storage services Utilizing CIFS access control mechanisms # 22

23 Uploading files (2/5) # 23

24 File dispersion k n E.g. k=6, n=8 Ensure availability despite of unreliable cloud storage provides. # 24

25 Secret Sharing aka Threshold schemes Objective: Divide a secret s2s in n pieces s1,,sn with 1. Knowledge of any k or more si pieces makes s easily computable. 2. Knowledge of any k-1 or fewer si pieces leave s completely undetermined (in the sense that all its possible values are equally likely). Sharing Input: s Dealer Share holders s1 Share holders store Reconstruction s1 s2 s2 si1 sn si2 sik Reconstructor sn Output: s* # 25

26 Secret Sharing: An informal example [Source: Visual Cryptography [NaSh1994] # 26

27 Secret Sharing: More formalism e r u c e! s ic ent t e ci r o ffi e th e e n c o a i t sp a Shamir's scheme m ot r Idea: It takes k points n a polynomial of degree k-1. o to define f t Sharing: Be a :=s2s In where bus is an infinite field. Source: Wikipedia Blakley's scheme [Blakley1979] Idea: Any n nonparallel n-dimensional hyper-planes intersect at a specific point. Sharing: Encode the secret as any single coordinate of the point of intersection. Recovering: 1. Calculating the planes' point of intersection. 2. Take a specified coordinate of that intersection. [Shamir1979] 0 Randomly choose (k-1) coefficients a1,a2, ak-12s to build f(x):=æaiáxi. Calculate shares sj:=[j,f(j)] mit j2ℕn. Recovering: Use Lagrange interpolation to find coefficients of the polynomial including constant term a0. # 27

28 Information Dispersal: Computationally secure secret sharing Rabin's scheme [Rabin1989] Be ai:=s2s where i=1, k. Rest as with Shamir's secret sharing. With a polynomial and shares of the same size as before, we can now share a value k times as long as before. Length of each share is only 1/k-th of the length of the secret, and if k shares must be sufficient for reconstruction, one can obviously not get shorter. Space optimal However, one might gain some information if he gets access to several shares Computationally secure More efficient codes: Need to be maximum distance separable to use k arbitrary shares for reconstruction Examples: Cauchy-Reed-Solomon, Liberation, Blaum-Roth [PSS2008] # 28

29 Uploading files (3/5) # 29

30 Cryptography: Confidentiality & Integrity AES-CBC + SHA256 AES-CBC + SHA256 AES-CBC + SHA256 AES-CBC + SHA256 # 30

31 Uploading files (4/5) # 31

32 Uploading files (5/5) Met a dat a # 32

33 Downloading files (1/3) X X # 33

34 Downloading files (2/3) X X # 34

35 Downloading files (3/3) Met a X dat a X # 35

36 Prototype implementations SecCSIE: [SGS11] NubiSave:[SBM+11] # 36

37 Cloud Computing What is it all about? Problems? π-box: Building your personal secure cloud Secure Cloud Storage Conclusion & Future Work # 37

38 Results so far & Future work Integration of existing cloud storage services (Cloud-of-Clouds) Proxy server for transparent mediation easy to use for end-user common scheme for enterprises High security and data sovereignty for the user Good performance but space for improvement Collaboration scenarios, file sharing, access by external entities Securing the meta data database Automatic classification of data Improving performance, e.g. scheduling algorithms, Caching/Prefetching, parallelisation Data store for database system # 38

39 Tomorrow's forecast: still cloudy with sunny spots Contact: # 39

40 References & Credits References [Blakley1979] G. R. Blakley: Safeguarding cryptographic keys; AFIPS Conference Proceedings Vol. 48, National Computer Conference (NCC) 1979, [MeGr2011] P. Mell and T. Grace: The NIST Definition of Cloud Computing. NIST Special Publication , September [NaSh1994] M. Naor and A. Shamir, Visual Cryptography, Eurocrypt 94. [PSS2008] J. S. Plank, S. Simmerman, C. D. Schuman: Jerasure: A Library in C/C++ Facilitating Erasure Coding for Storage Applications Version 1.2. Technical Report CS , University of Tennessee, [Rabin1989] M. O. Rabin: Efficient Dispersal of Information for Security, Load Balancing, and Fault Tolerance; Journal of the ACM 36/2 (1989) [SBM+2011] J. Spillner, G. Bombach, S. Matthischke, R. Tzschicholz, and A. Schill: Information Dispersion over Redundant Arrays of Optimal Cloud Storage for Desktop Users. In: IEEE International Conference on Utility and Cloud Computing. Melbourne, Australien, December [SGS2011] R. Seiger, S. Groß, and A. Schill: A Secure Cloud Storage Integrator for Enterprises. In: International Workshop on Clouds for Enterprises. Luxemburg, September [Shamir1979] A. Shamir: How to Share a Secret; Communications of the ACM 22/11 (1979) Credits Kudos to Ronny Seiger and Josef Spillner, both for providing slides and contributing to the research work. Furthermore, I would like to thank Marc Mosch for the best styled graphics. # 40