1 Privacy – Preserving Data Dissemination in Untrusted CloudIEEE Cloud 2017 Privacy – Preserving Data Dissemination in Untrusted Cloud Denis Ulybyshev, Bharat Bhargava, Donald Steiner, Leon Li, Jason Kobes, Harry Halpin, Miguel Villarreal – Vasquez, Aala Alsalem, Rohit Ranchal Computer Science, CERIAS, Purdue University Northrop Grumman MIT IBM 1 1 2 2 2 3 1 1 4 1 2 3 4 1
2 Outline Problem Statement Related Work Core DesignThesis contributions Demonstrations and Experiments Future Work ACKNOWLEDGMENT This work was funded by the Northrop Grumman Cybersecurity Research Consortium. Paper approved for public release by Northrop Grumman, Case # The prototype was implemented in collaboration with Northrop Grumman and W3C / MIT and presented internally to Northrop Grumman in April, We are thankful to Prof. Leszek Lilien and Prof. Weichao Wang for their collaboration and valuable feedback. 2
3 Problem Statement Privacy – preserving role – based and attribute – based data dissemination Authorized service can only access data items for which it is authorized Role – based data dissemination Attribute- and context – based data dissemination Periodic computation of trust level of services 3
4 Problem Statement Data Owner Cloud ServerActive Bundle Cloud Server Patient’s EHR (Active Bundle) Contact, Medical and Billing Information Web Crypto Authentication Doctor - Contact Info - Medical Info - Billing Info Web Crypto Authentication Insurance - Contact Info - E(Medical Info) - Billing Info Web Crypto Authentication Researcher - E(Contact Info) - Medical Info - Billing Info Doctor Insurance Researcher Scenario of EHR Dissemination in Cloud (suggested by Dr. Leon Li, NGC) 4
5 Problem Statement D Data dissemination in SOA Data (D) = {d1,.., dn}` Data (D) = {d1,.., dn} Access Control Policies (P) = {p1,.., pk} D TRUSTED DOMAIN D, P Service 2 forwards D and P to other cloud CLOUD PROVIDER 1 D, P CLOUD PROVIDER 2 D, P Data Leaks ? D, P D, P D, P SERVICE 1 d1 SERVICE 2 d2 UNKNOWN DOMAIN SERVICE 3 d3 5
6 Research Solutions Privacy – Preserving Data Dissemination based on: - Active Bundles with policies and policy enforcement engine - Central Monitor constantly re-computing trust level of services - Secure Browser with detection of its cryptographic capabilities R. Ranchal, D. Ulybyshev, P. Angin, and B. Bhargava. “Policy-based Distributed Data Dissemination,” CERIAS Security Symposium, April 2015 (Best poster award, 1 out of 43) 6
7 Research Solutions Features: Is independent from TTPData owner’s availability is not required Dissemination considers client's attributes Crypto capabilities of a browser Trust level (which is constantly recomputed) Authentication method Type of client’s device On-the-fly data updates are supported Secure key generation scheme 7
8 Related Work Policy-based Data DisseminationPolicy enforcement at browser's side [8] (Prof. Matteo Maffei, Saarland University, Germany) Micro-policies specified in terms of tags, used to label URLs, network connections, cookies, etc and a transfer function Transfer function defines permitted operations by the browser based on tags. Trust level of clients is not constantly monitored and recalculated in the data dissemination model Requires browser’s code modification Implemented as a Chrome plugin (MiChrome [9] ) 8
9 Related Work Policy-based Data Dissemination“Encore” (sticky policies) system [7] Policies and data are made inseparable Policies are enforced by TTP Policies are prone to tamper attacks from malicious recipients Prone to Trusted Third Party (TTP)-related issues Privacy – preserving information brokering (PPIB) [6] Divides processing among multiple brokers, no single component has enough control to make a meaningful inference from data disclosed to it Prone to centralized TTP (manages keys, metadata) issues 9
10 Framework Architecture10
11 Attribute and Role–based Data Dissemination ACCESSIBLE TEXT Browser’s Crypto Level: High Authentication Method: Fingerprint Client’s device: Desktop Source network: Corporate Intranet Role: Doctor AUTHENTICATED CLIENT Browser’s Crypto Level: Low Authentication Method: Password Client’s device: Mobile Source network: Unknown Role: Insurance Agent AUTHENTICATED CLIENT INACCESSIBLE TEXT 1 ACCESSIBLE TEXT INACCESSIBLE TEXT 2 11
12 AB Core Design Active Bundle (AB) parts: Sensitive data:[10], [11] Sensitive data: Encrypted data items Metadata: describe AB and its access control policies Policies [14], [15] manage AB interaction with services and hosts Policy Engine [18]: enforces policies specified in AB Provides tamper-resistance of AB [1] 12
13 AB Example Key-value pair stored in the Active Bundle:{ “ab.patientID” : “Enc( )” } { “ab.name” : “Enc(‘Monica Latte’)” } ALLOW Resource patientID Subject's Role Doctor, Insurance, Researcher Action Read Policy Examples: ALLOW Resource name Subject's Role Doctor, Insurance Action Read 13
14 Key Derivation Module (javax.crypto SecetKeyFactory)Key Generation Aggregation{di} ( - Generated AB modules execution info; - Digest(AB Modules), - Resources: authentication code + CA certificate, authorization code, applicable policies + evaluation code) Ki Key Derivation Module (javax.crypto SecetKeyFactory) ENCki (di) AB Template [1] used to generate new ABs with data and policies (specified by data owner) AB Template includes implementation of invariant parts (monitor) and placeholders for customized parts (data and policies) AB Template is executed to simulate interaction between AB and service requesting access to each data item of AB 14
15 Key Generation (Cont.) Info generated during the execution and digest (modules) and AB resources are collected into a single value Value for each data item is input into a Key Derivation module (such as SecretKeyFactory, PBEKeySpec, SecretKeySpec from javax.crypto library) Key Derivation module outputs the specific key relevant to the data item This key is used to encrypt the related data item [1] 15
16 Key Derivation Module (javax.crypto SecetKeyFactory)Aggregation{di} ( - Generated AB modules execution info; - Digest(AB Modules), - Resources: authentication code + CA certificate, authorization code, applicable policies + evaluation code) Ki Key Derivation Module (javax.crypto SecetKeyFactory) DECki (Enc[di]) AB receives data item request from a service AB authenticates the service and authorizes its request (evaluates access control policies) [1] 1. "Cross-Domain Data Dissemination and Policy Enforcement", R. Ranchal, PhD Thesis, Purdue University, Jun 16
17 Key Derivation (Cont.) Info generated during the AB modules execution in interaction with service, and digest (AB modules) and AB resources are aggregated into a single value for each data item [1] Value for each data item is input into the Key Derivation module Key Derivation module outputs specific key relevant to data item This key is used decrypt the requested data item If any module fails (i.e. service is not authentic or the request is not authorized) or is tampered, the derived key is incorrect and the data is not decrypted 17
18 Other Key Distribution MethodsCentralized Key Management Service TTP used for key storage and distribution TTP is a single point of failure Key included inside AB Prone to attacks! 18
19 Tamper Resistance of ABKey is not stored inside AB [2] Separate symmetric key is used for each separate data value Ensure protection against tampering attacks Aggregation{di} (Execution info; Digest(AB Modules); Resources) Aggregation{di} ( Tampered ( Execution info; Resources) ) Key Derivation Module Ki DECki (di) di K’i DECk’i (di) wrong di 19
20 AB Use Cases Hospital Information System (collection of EHRs)Doctor, Researcher and Insurance are authorized for different parts of patient's EHR [5] Database of EHRs is hosted by untrusted cloud provider Secure is AB Entire can be sent to the whole mailing list Recipients are authorized for different fragments of It is guaranteed for the sender that each recipient will only see those fragments it is authorized for No need for multiple mailing lists for different authorization levels Online shopping Decentralized data accesses: data can travel across the services C. Qu, D. Ulybyshev, B. Bhargava, R. Rohit, and L. Lilien. "Secure Dissemination of Video Data in Vehicle-to-Vehicle Systems.” 6th Intl. Workshop on Dependable Network Computing and Mobile Systems (DNCMS2015), Sep. 2015 20
21 AB Use Cases: Online Shopping21
22 NGC TechFest’16 Demo: Electronic Health Record Dissemination in CloudActive Bundle: Contact, Medical and Billing Information Hospital (NodeJS Server) Researcher - E(Contact Info) - Medical Info - Billing Info Insurance - Contact Info - E(Medical Info) - Billing Info Doctor - Contact Info - Medical Info - Billing Info (10) (2) (4) (9) (1) (3) (1) HTTP GET Request (2) Hospital’s Web Page (3) HTTP POST with Data Request and Role (5) Authentication Server Client (Browser) (6) (7) (8) (4) HTTP 302 with AB Request and Role (5) HTTP Get Request (6) AS Web Page (7) HTTP POST with Credentials (8) HTTP 302 with Ticket (9) HTTP Get Request with Ticket (10) Data provided by AB 22
23 Data dissemination featuresData Dissemination based on: Access control policies Trust level of a subject (service, user) Context (e.g. emergency vs. normal) Security level of client’s browser (crypto capabilities) [16], [17] Authentication method (password-based, fingerprint, etc) Source network (secure intranet vs. unknown network) Type of client’s device: desktop vs. mobile (detected by Authentication Server) 23
24 Lightweight encryptionCan be used in Active Bundle instead of regular AES [1] Cipher Key size [bits] Block size [bits] Throughput at MHz [kbit/sec] Relative Throughput (% of AES) Hardware-oriented block ciphers DES 56 64 29.6 38.4 DESXL 184 30.4 39.3 Hight 128 80.3 104.2 Software-oriented block ciphers AES 77.1 100.0 IDEA 94.8 123 24
25 Notes 1. Assumption: hardware and OS are trusted2. Data is extracted from Active Bundle at a server side and send to client via https - Data can't be tampered 25
26 Contributions Contributes to Data Privacy, Integrity and Confidentiality Dissemination does not require data owner’s availability TTP-independent for recipient’s key generation Trust level of subjects is constantly recalculated On-the-fly key generation Supports data updates for multiple subjects Agnostic to policy language and evaluation engine Tamper-resistance: data and policies integrity is provided Compatible with industry-standard SOA / cloud frameworks 26
27 Evaluation Performance overhead of Active Bundle with detection of browser's crypto capabilities on / off 27
28 Evaluation Performance overhead of Active Bundle for data request from insecure / secure browser 28
29 Evaluation Performance overhead of Active Bundle, hosted by Google Cloud 29
30 Deliverables Prototype implementation:Privacy – Preserving Data Dissemination Prototype Active Bundle Module AB implementation as an executable JAR file AB API implementation using Apache Thrift RPC framework Policy specification in JSON and evaluation using WSO2 Balana Source code: Documentation: Deployment and user manual Demo video [13] “Data dissemination/provenance in untrusted cloud” 30
31 Future Work Lightweight encryption schemes in Active Bundle instead of AES Isolated AB Execution (Linux Docker Containers) Data Leakage Detection Encrypted Search over Database of Active Bundles 31
32 References R. Ranchal, “Cross-domain data dissemination and policy enforcement,” PhD Thesis, Purdue University, Jun. 2015 C. Qu, D. Ulybyshev, B. Bhargava, R. Rohit, and L. Lilien. "Secure Dissemination of Video Data in Vehicle-to-Vehicle Systems.” 6th Intl. Workshop on Dependable Network Computing and Mobile Systems (DNCMS2015), Sep. 2015 L. Lilien and B. Bhargava, ”A scheme for privacy-preserving data dissemination,” IEEE Trans. on Systems, Man and Cybernetics, Part A: Systems and Humans, vol. 36(3), May 2006, pp R. Ranchal, D. Ulybyshev, P. Angin, and B. Bhargava. “Policy-based Distributed Data Dissemination,” CERIAS Security Symposium, April 2015 (Best poster award) D. Ulybyshev, B. Bhargava, L. Li, J. Kobes, D. Steiner, H. Halpin, B. An, M. Villarreal, R. Ranchal. “Authentication of User’s Device and Browser for Data Access in Untrusted Cloud,” CERIAS Security Symposium, April 2016. F. Li, B. Luo, P. Liu, D. Lee, and C.-H. Chu, “Enforcing secure and privacy- preserving information brokering in distributed information sharing,” IEEE Transactions on Information Forensics and Security, vol. 8, no. 6, pp. 888–900, 2013. S. Pearson and M. C. Mont, “Sticky policies: an approach for managing privacy across multiple parties,” IEEE Computer, no. 9, pp. 60–68, 2011. S. Calzavara, R. Focardi, N. Grimm, M. Maffei, “Micro-policies for web session security”. Computer Security Foundations Symp. (CSF), 2016 IEEE 29th (pp ), Jun. 2016 Anonymus, “Micro-policies for web session security,” 2016, available at https://sites.google.com/site/micropolwebsese, accessed: Feb.2017
33 References 10. L. Ben Othmane and L. Lilien, “Protecting privacy in sensitive data dissemination with active bundles,” 7-th Annual Conf. on Privacy, Security and Trust (PST 2009), Saint John, New Brunswick, Canada, Aug. 2009, pp 11. L. Lilien and B. Bhargava, ”A scheme for privacy-preserving data dissemination,” IEEE Trans. on Systems, Man and Cybernetics, Part A: Systems and Humans, vol. 36(3), May 2006, pp 12. B. Bhargava, “Secure/resilient systems and data dissemination/provenance,” NGCRC Project Proposal, CERIAS, Purdue University, Aug.2016 13. D. Ulybyshev, B.Bhargava, “Secure dissemination of EHR,” demo video https://www.dropbox.com/s/30scw1srqsmyq6d/BhargavaTeam_DemoVideo_Spring16.wmv?dl=0 14. “Lightweight data-interchange format JSON,” , accessed: Oct.2016 15. “eXtensible access control markup language (XACML) version 3.0,” accessed: Oct. 2016 16. “W3C Web Cryptography API,”https://www.w3.org/TR/WebCryptoAPI/, accessed: Oct.2016 17. “Web authentication: an API for accessing scoped credentials,” , accessed: Oct.2016 , accessed: Oct.2016 18. “WSO2 Balana Implementation,” https://github.com/wso2/balana , accessed: Oct.2016