Title:

On Traceability of Attribute-Based Encryption

Description:

Attribute based encryption (ABE) provides one-to-many encryption. Since attributes are shared between users, a malicious user leaking his/her private key is at low risk of being caught. For this reason traceability has been studied in the field of ABE research. Aside from traceability, non-monotonic structure is a feature which supports the applicability of ABE schemes. By utilizing one of the latest scheme in traceability aspect and a scheme in non-monotonic access policy aspect, this thesis aims to propose an ABE scheme which supports both traceability and non-monotonic access policies. By using the traceable ABE scheme of Liu and Wong as foundation, this thesis build upon the non-monotonic extension by Thatmann et al. Furthermore this thesis also extends the implementation of Liu and Wong's scheme called jTR-ABE with the non-monotonic elements. Based on jTR-ABE and the non-monotonic extension, a performance evaluation is performed to measure the impact of the non-monotonic extension. It is shown that on average, under the same variables and circumstances, there has been no significant impact of the non-monotonic extension. To the best knowledge of the author, this is the first ABE scheme which supports large attribute universe, direct user revocation, and blackbox traceability as well as non-monotonic access policy.

Supervisor: Dirk Thatmann

Type:  Master Thesis

Duration: 6 months