Controllable Identifier Measurements for Private Authentication With Secret Keys

Abstract

The problem of secret-key based authentication under a privacy constraint on the source sequence is considered. The identifier measurements during authentication are assumed to be controllable via a cost-constrained "action" sequence. Single-letter characterizations of the optimal trade-off among the secret-key rate, storage rate, privacy-leakage rate, and action cost are given for the four problems where noisy or noiseless measurements of the source are enrolled to generate or embed secret keys. The results are relevant for several user-authentication scenarios including physical and biometric authentications with multiple measurements. Our results include, as special cases, new results for secret-key generation and embedding with action-dependent side information without any privacy constraint on the enrolled source sequence.

Key Agreement Using Physical Identifiers for Degraded and Less Noisy Authentication Channels

“…The privacy constraint is imposed to minimize the information leakage of the identifiers, and in general, its analysis becomes challenging especially when the noise in the enrollment phase is taken into account [21]. An extension of the work [31] by considering noisy EC and action cost at the decoder was presented in [35], and in both [31] and [35], it was shown that the resulting expressions of the capacity regions involve two auxiliary random variables for a general class of ACs.…”

“…In a similar manner, we also investigate the capacity regions of the authentication systems for similar classes of channels, but the models and the point to which we direct our attention are different from those of [37], [38]. More precisely, we deal with the models with separate measurements as in [35], and focus on the structure of AC, e.g., the main channel is less noisy than Eve's channel or Eve's channel is degraded with respect to the main channel, to simplify the expressions of the capacity regions with two auxiliary random variables that have been characterized in the paper.…”

Biometric Identification Systems with Noisy Enrollment for Gaussian Sources and Channels

“…By letting n → ∞ and δ ↓ 0, the capacity region of the chosen-secret BIS model is contained in the right-hand side of (20).…”

“…By using an additional private key, user's privacy-leakage can be made negligible [15,16]. Another scenario, that is, the BIS with one user, was extensively examined in [8,[17][18][19][20][21][22]. More precisely, in [17,18], the relation of secret-key and privacy-leakage rates was analyzed.…”

“…It is worthwhile noting that in [8], a successful attempt for characterizing the capacity region of the BIS with one user for HSM was first made. The works of [8] was extended to constrain the action cost for the decoder in [20], and to consider twoenrollment systems for the same hidden source, where the encoders do not trust each other [21]. Moreover, in [22], the secret-key capacity of a multi-enrollment system, in which the decoder is required to estimate all secret keys generated in the earlier enrollments, was formulated.…”