伺服器輔助秘密運算 機置及其應用 Server-aided Secret Computation -- Schemes and Applications

1. 伺服器輔助秘密運算機置及其應用Server-aided Secret Computation -- Schemes and Applications 洪國寶 AI Lab

2. Server-aided Secret Computation • Secret computation outsourcing • when an entity (the client) needs to execute a task but does not have the appropriate computation power to perform it. The task is then delegated to external servers which have the sufficient calculation power. • The main security issue of a secure outsourcing is to delegate a computation to a set of untrusted servers without revealing neither the input nor the output

3. Server-aided Secret Computation • The key idea is for the client to do some pre-processing over the input before sending it to the servers, and then to do some post-processing over the servers result to recover the final computation output. • There are two main pre-processing methods to hide the secret input: disguise and encryption. • The disguise is to apply some functional or mathematical transformations over the input. • The encryption is a particular disguise method which consists in encrypting the input using a secret key.

4. Server-aided Secret Computation A simple example (for RSA signature scheme)

5. Server-aided Secret Computation

6. Server-aided Secret Computation

7. 本研究計畫之目的 • Our research goals are four-fold: (1)to study basic tools for designing secure computation outsourcing schemes, (2)to design practical server-aided secret computation for exponentiation-based schemes, (3)to design practical server-aided secret computation for elliptic-curve-based schemes, and (4) to design and implement practical building blocks for realizing CaaS (cryptography as a (ubicomp) service).

8. Construct models and study basic tools • Model • For security analysis • Basic tools • 巧思

9. Design server-aided exponentiation schemes • Studied and analyzed basic tools and schemes for server-aided secure exponentiation; • Designed new secure server-aided RSA signature generation schemes; and • Designed server-aided signature/ certificate/identification verification schemes.

10. Point multiplication based schemes • Studied and analyzed basic tools and schemes for server-aided elliptic curve operations; • Designed secure server-aided ECDSA and ECDH schemes; • Designed server-aided ECDH schemes

11. Pairing-based schemes and applications • Designed secure server-aided pairing based applications.

12. Implement server-aided computation • Designed building blocks for realizing cryptography as a service; and • Designed schemes for supporting email server that accommodates user’s encrypted emails where the server needs to perform user identification and helps user with decryption.

13. Implement server-aided computation • Design hardware/software architecture and interface • Implement Security Association Negotiation • Develop server/client programs

14. Implementation • 用於本計畫之實驗設計實作 • 個人數位助理 • 小筆電 • OS, language • Query the communication speed, and the computational power of PDA (and/or smart card, mobile phone, etc.) and server (PC, workstation, etc.)