On the economics of offline password cracking

J Blocki, B Harsha, S Zhou - 2018 IEEE Symposium on Security …, 2018 - ieeexplore.ieee.org
We develop an economic model of an offline password cracker which allows us to make
quantitative predictions about the fraction of accounts that a rational password attacker …

Efficiently computing data-independent memory-hard functions

J Alwen, J Blocki - Annual International Cryptology Conference, 2016 - Springer
A memory-hard function (MHF) f is equipped with a space cost σ and time cost τ parameter
such that repeatedly computing f_ σ, τ on an application specific integrated circuit (ASIC) is …

Differentially private password frequency lists

J Blocki, A Datta, J Bonneau - Cryptology ePrint Archive, 2016 - eprint.iacr.org
Given a dataset of user-chosen passwords, the frequency list reveals the frequency of each
unique password. We present a novel mechanism for releasing perturbed password …

Designing proof of human-work puzzles for cryptocurrency and beyond

J Blocki, HS Zhou - Theory of Cryptography: 14th International Conference …, 2016 - Springer
We introduce the novel notion of a Proof of Human-work (PoH) and present the first
distributed consensus protocol from hard Artificial Intelligence problems. As the name …

Spaced repetition and mnemonics enable recall of multiple strong passwords

J Blocki, S Komanduri, L Cranor, A Datta - arXiv preprint arXiv:1410.1490, 2014 - arxiv.org
We report on a user study that provides evidence that spaced repetition and a specific
mnemonic technique enable users to successfully recall multiple strong passwords over …

A novel approach for designing authentication system using a picture based P300 speller

N Rathi, R Singla, S Tiwari - Cognitive Neurodynamics, 2021 - Springer
Due to great advances in the field of information technology, the need for a more reliable
authentication system has been growing rapidly for protecting the individual or …

Please do not use!? _ or your license plate number: Analyzing password policies in german companies

E Gerlitz, M Häring, M Smith - … on Usable Privacy and Security (SOUPS …, 2021 - usenix.org
Password composition policies (PCPs) set rules that are intended to increase the security of
user-chosen passwords. We conducted an online survey and investigated the employee …

Method and system of providing a picture password proof of knowledge as a web service

RH Thibadeau, JD Donnell - US Patent 9,813,411, 2017 - Google Patents
6, 249, 868 B16/2001 Sherman et al. 6, 411, 283 B1 6/2002 Murphy 6, 658, 328 B1 12/2003
Alrabady et al. 6, 934, 860 B1 8/2005 Goldstein 6, 983, 065 B1 1/2006 Akgul et al. 7, 243 …

CASH: A cost asymmetric secure hash algorithm for optimal password protection

J Blocki, A Datta - 2016 IEEE 29th Computer Security …, 2016 - ieeexplore.ieee.org
An adversary who has obtained the cryptographic hash of a user's password can mount an
offline attack to crack the password by comparing this hash value with the cryptographic …

A second look at password composition policies in the wild: Comparing samples from 2010 and 2016

P Mayer, J Kirchner, M Volkamer - Thirteenth Symposium on Usable …, 2017 - usenix.org
In this paper we present a replication and extension of the study performed by Florêncio and
Herley published at SOUPS 2010. They investigated a sample of US websites, examining …