1 / 19

Improving Attribute-Based Encryption Efficiency Online/Offline

Learn about Attribute-Based Encryption concepts, challenges, and the innovative Online/Offline approach to improving encryption efficiency. Presented by experts in the field, Susan Hohenberger, Brent Waters, and Shai Halevi. Understand the need for secret keys to access data and the disconnect between policy and mechanism in encryption. Dive into the technical aspects of ABE, encryption costs, offline key encapsulation mechanisms, and more. Explore the challenges and solutions in ABE systems with the Rouselakis-Waters framework. Advance your knowledge in encryption technology with this comprehensive overview.

rayl
Download Presentation

Improving Attribute-Based Encryption Efficiency Online/Offline

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Online/Offline Attribute-Based Encryption Susan Hohenberger Brent Waters Presented by Shai Halevi

  2. SK Access Control by Encryption Idea: Need secret key to access data PK

  3. OR AND Internal Affairs Undercover Central Rethinking Encryption Problem: Disconnect between policy and mechanism • Who matches this? Am I allowed to know? • What if they join later?

  4. Attribute-Based Encryption [SW05,GPSW06,…] MSK Public Parameters SK Authority Functionality: output message if f(S) = true Sis not hidden CT: S (set of attributes) Key: f 4

  5. Costs of Encryption Typical cost ~ 1-3 exponentiations per attribute (KP-ABE) • Problems: • Bursty encryption periods • Low power devices 5

  6. Can we move most of the encryption costs offline?

  7. Online/Offline ABE Offline: ABE Key Encapsulation Mechanism (KEM) Intermediate Ciphertext (IT) Online: Attribute set S Ciphertext 7

  8. Some Prior Online/Offline Work Signatures: EGM96, ST01, … IBE: GMC08, … Also in other contexts such as Multi-party computation 8

  9. The rest of the talk • Warmup with IBE (2) Our Online/Offline Construction (3) “Pooling” for better efficiency 9

  10. Brief Background on Bilinear maps High Level: single multiplication 10

  11. Structure Matters Difficulty of online/offline on Boneh-Franklin IBE CT:

  12. IBE Warmup (Boneh-Boyen04 ish) Offline: Online (ID): “Correction Factor” KeyGen(ID): Decrypt: 12

  13. Challenges for ABE • Many ABE systems do not have right structure (e.g. GPSW06) • More complex access policies Use Rouselakis-Waters 2013 13

  14. System Setup

  15. OR AND Key Generation • Share a according to formula • Generate key components

  16. Encryption Offline: Online (): System uses n attributes per CT (address later) 16

  17. Decryption & Proof Decryption: • Brings together CT randomness and key shares • Uses correction factor per node • Details in paper. Proof: Reduce to security of RW13 ABE scheme

  18. Extensions Pooling: Flexible number of attributes per ciphertext Online/Offline Key Gen: Matches CP-ABE 18

  19. Thank you

More Related