TY - GEN

T1 - Quantitative evaluation of unlinkable ID matching schemes

AU - Nohara, Yasunobu

AU - Inoue, Sozo

AU - Baba, Kensuke

AU - Yasuura, Hiroto

PY - 2005

Y1 - 2005

N2 - As pervasive computing environments become popular, RFID devices, such as contactless smart cards and RFID tags, are introduced into our daily life. However, there exists a privacy problem that a third party can trace user's behavior by linking device's ID. The concept of unlinkability, that a third party cannot recognize whether some outputs are from the same user, is important to solve the privacy problem. A scheme using hash function satisfies unlinkability against a third party by changing the outputs of RFID devices every time. However, the schemes are not scalable since the server needs O(N) hash calculations for every ID matching, where N is the number of RFID devices. In this paper, we propose the K-steps ID matching scheme, which can reduce the number of the hash calculations on the server to O(log N). Secondly, we propose a quantification of unlinkability using conditional entropy and mutual information. Finally, we analyze the K-steps ID matching scheme using the proposed quantification, and show the relation between the time complexity and unlinkability.

AB - As pervasive computing environments become popular, RFID devices, such as contactless smart cards and RFID tags, are introduced into our daily life. However, there exists a privacy problem that a third party can trace user's behavior by linking device's ID. The concept of unlinkability, that a third party cannot recognize whether some outputs are from the same user, is important to solve the privacy problem. A scheme using hash function satisfies unlinkability against a third party by changing the outputs of RFID devices every time. However, the schemes are not scalable since the server needs O(N) hash calculations for every ID matching, where N is the number of RFID devices. In this paper, we propose the K-steps ID matching scheme, which can reduce the number of the hash calculations on the server to O(log N). Secondly, we propose a quantification of unlinkability using conditional entropy and mutual information. Finally, we analyze the K-steps ID matching scheme using the proposed quantification, and show the relation between the time complexity and unlinkability.

UR - http://www.scopus.com/inward/record.url?scp=33749005411&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749005411&partnerID=8YFLogxK

U2 - 10.1145/1102199.1102212

DO - 10.1145/1102199.1102212

M3 - Conference contribution

AN - SCOPUS:33749005411

SN - 1595932283

SN - 9781595932280

T3 - WPES'05: Proceedings of the 2005 ACM Workshop on Privacy in the Electronic Society

SP - 55

EP - 60

BT - WPES'05

PB - Association for Computing Machinery (ACM)

T2 - WPES'05: 2005 ACM Workshop on Privacy in the Electronic Society

Y2 - 7 November 2005 through 7 November 2005

ER -