Secret key-based authentication with a privacy constraint

Abstract

We consider problems of authentication using secret key generation under a privacy constraint on the enrolled source data. An adversary who has access to the stored description and correlated side information tries to deceive the authentication as well as learn about the source. We characterize the optimal tradeoff between the compression rate of the stored description, the leakage rate of the source data, and the exponent of the adversary's maximum false acceptance probability. The related problem of secret key generation with a privacy constraint is also studied where the optimal tradeoff between the compression rate, leakage rate, and secret key rate is characterized. It reveals a connection between the optimal secret key rate and security of the authentication system.

Controllable Identifier Measurements for Private Authentication With Secret Keys

“…Consider the compression-leakage-key region given in [19,Theorem 2] for the generated-secret model and a visible source. We compare this region with the rate region R gs to illustrate the effects of the cost-constrained action sequence.…”

“…We compare this region with the rate region R gs to illustrate the effects of the cost-constrained action sequence. In particular, we observe that the action A appears as a conditioning random variable in each mutual information term in [19,Theorem 2], the new storage and privacy-leakage rate limits are increased by the rate-distortion coding amount of I(X; A), and the probability distribution of A is limited by an expected cost constraint. Therefore, the cost-constrained action sequence A n brings the possibility of enlarging the rate region, which recovers the rate region in [19,Theorem 2] by choosing a constant action with fixed cost.…”

“…The results in Theorems 1 and 2 include, as special cases, results for one-round secret-key generation and embedding, respectively, that extend the results in [10], where there is no privacy constraint on the source sequence, i.e., ∆ = ∆ max = H(X) in Definitions 2 and 4, with actiondependent side information. Moreover, Theorem 1 can also be seen as an extension of the result in [19] because we additionally capture cost-constrained action-dependent decoder measurements.…”

“…Multiple identifier measurements both at the encoder and decoder are also possible by considering a hidden identifier. Similar to [19], correlated information at the eavesdropper is also considered here unlike in [4], [5], and [18], which is a realistic assumption especially for biometric identifiers. The key-storage-leakage-cost region for secret-key generation from an identifier with a cost-constrained action at the decoder and a noiseless (visible) output at the encoder is given first in the conference version of this paper [1].…”

Secret Key-Based Identification and Authentication With a Privacy Constraint

“…i) When there is only one user in the database, i.e., |W (n) | = 1, the problem reduces to authentication with a privacy constraint studied in [12] (see e.g., Fig. 2).…”