An Improved Group Signature Scheme with VLR over Lattices

For group signatures (GS) supporting membership revocation, verifier-local revocation (VLR) mechanism is the most flexible choice. As a post-quantum secure cryptographic counterpart of classical schemes, the first dynamic GS-VLR scheme over lattices was put forward by Langlois et al. at PKC 2014; furthermore, a corrected version was shown at TCS 2018. However, both designs are within Bonsai trees and featuring bit-sizes of group public-key and member secret signing key proportional to log N where N is the group size; therefore, both schemes are not suitable for a large group. In this paper, we provide an improved dynamic GS-VLR over lattices, which is efficient by eliminating a O log N factor for both sizes. To realize the goal, we adopt a more efficient and compact identity-encoding technique. At the heart of our new construction is a new Stern-type statistical zero-knowledge argument of knowledge protocol which may be of some independent cryptographic interest.

Lattice-Based Logarithmic-Size Non-Interactive Deniable Ring Signatures

Deniable ring signature can be regarded as group signature without group manager, in which a singer is capable of singing a message anonymously, but, if necessary, each ring member is allowed to confirm or disavowal its involvement in the signature via an interactive mechanism between the ring member and the verifier. This attractive feature makes the deniable ring signature find many applications in the real world. In this work, we propose an efficient scheme with signature size logarithmic to the cardinality of the ring. From a high level, we adapt Libert et al.’s zero-knowledge argument system (Eurocrypt 2016) to allow the prover to convince the verifier that its witness satisfies an additional condition. Then, using the Fait-Shamir transformation, we get a non-interactive deniable ring signature scheme that satisfies the anonymity, traceability, and non-frameability under the small integer solution assumption in the random oracle model.

Consciousness

Wilson considers whether consciousness is either Weakly or Strongly emergent. Some have seen consciousness as the best case for a Strongly emergent phenomenon, reflecting that subjective or qualitative aspects of consciousness depart so greatly from physical features that some anti-physicalist view (perhaps Strong emergence) must be true. Wilson considers two such ‘explanatory gap’ strategies, associated with the knowledge argument (Jackson 1982, 1986) and the conceivability argument (Chalmers 1996, 2009). She argues that each strategy fails, for reasons not much previously explored; hence while the Strong emergence of consciousness remains an open empirical possibility, there is currently no motivation for taking this to actually be so. Wilson then argues that attention to the determinable nature of qualitative conscious states provides good reason to take such states to be Weakly emergent by lights of a determinable-based account, and defends the application of such an account to mental states against various objections.

Nonconceptualism as the key to a new physicalist strategy in the knowledge argument

This paper presents and defends an alternative version to the so-called strategy of phenomenal concepts (aka PCS) in defense of type B materialism in Jackson’s knowledge argument. Endorsing Ball and Tye’s criticism, I argue in favor of the following claims. First: Mary’s newly acquired content is nonconceptual in the light of all available criteria. Second: Mary’s acquisition of such content is precisely what allows us to explain, at least in part, both her epistemic progress (once released from her confinement) and the increase in her expertize regarding her old PHENOMENAL RED. However, although the acquisition of such nonconceptual content is indispensable, it is sufficient to explain Mary’s epistemic progress. Third: assuming that concepts are mental files, after undergoing the visual experiences of red for the first time, such newly acquired nonconceptual content goes through a process of “digitization” so that it can be stored in the mental file PHENOMENAL RED. Fourth and final claim: it is based on this concept of PHENOMENAL RED, now phenomenally enriched by the newly acquired nonconceptual content, that Mary is able to identify introspectively the phenomenal red of her new experience.

Artificial Consciousness, Meta-Knowledge, and Physical Omniscience

Previous work [Chrisley & Sloman, 2016, 2017] has argued that a capacity for certain kinds of meta-knowledge is central to modeling consciousness, especially the recalcitrant aspects of qualia, in computational architectures. After a quick review of that work, this paper presents a novel objection to Frank Jackson’s Knowledge Argument (KA) against physicalism, an objection in which such meta-knowledge also plays a central role. It is first shown that the KA’s supposition of a person, Mary, who is physically omniscient, and yet who has not experienced seeing red, is logically inconsistent, due to the existence of epistemic blindspots for Mary. It is then shown that even if one makes the KA consistent by supposing a more limited physical omniscience for Mary, this revised argument is invalid. This demonstration is achieved via the construction of a physical fact (a recursive conditional epistemic blindspot) that Mary cannot know before she experiences seeing red for the first time, but which she can know afterward. After considering and refuting some counter-arguments, the paper closes with a discussion of the implications of this argument for machine consciousness, and vice versa.

Classical zero-knowledge arguments for quantum computations

We show that every language in QMA admits a classical-verifier, quantum-prover zero-knowledge argument system which is sound against quantum polynomial-time provers and zero-knowledge for classical (and quantum) polynomial-time verifiers. The protocol builds upon two recent results: a computational zero-knowledge proof system for languages in QMA, with a quantum verifier, introduced by Broadbent et al. (FOCS 2016), and an argument system for languages in QMA, with a classical verifier, introduced by Mahadev (FOCS 2018).