Improved Zero-Knowledge Identification with Lattices

Improved Zero-Knowledge Identification with Lattices

Zero-knowledge identification schemes solve the problem of authenticating one party to another via an insecure channel without disclosing any additional information that might be used by an impersonator. In this paper we propose a scheme whose security relies on the existence of a commitment scheme and on the hardness of worst-case lattice problems. We adapt a code-based identification scheme d...

Zero-Knowledge Password Policy Check from Lattices

Passwords are ubiquitous and most commonly used to authenticate users when logging into online services. Using high entropy passwords is critical to prevent unauthorized access and password policies emerged to enforce this requirement on passwords. However, with current methods of password storage, poor practices and server breaches have leaked many passwords to the public. To protect one’s sen...

Zero-Knowledge Proxy Re-Identification Revisited

Zero-knowledge proxy re-identification (ZK-PRI) has been introduced by Blaze et al. in 1998 together with two other well known primitives of recryptography, namely proxy re-encryption (PRE) and proxy re-signature (PRS). A ZK-PRI allows a proxy to transform an identification protocol for Alice into an identification protocol for Bob using a re-proof key. PRE and PRS have been largely studied in ...

Zero - Knowledge with Publi

Improved Setup Assumptions for 3-Round Resettable Zero Knowledge

In the bare public-key model, introduced by Canetti et al. [STOC 2000], it is only assumed that each verifier deposits during a setup phase a public key in a file accessible by all users at all times. As pointed out by Micali and Reyzin [Crypto 2001], the notion of soundness in this model is more subtle and complex than in the classical model. Indeed Micali and Reyzin have introduced four diffe...