Cryptology ePrint Archive: Report 2015/009

Rig: A simple, secure and flexible design for Password Hashing

Donghoon Chang and Arpan Jati and Sweta Mishra and Somitra Kumar Sanadhya

Abstract: Password Hashing, a technique commonly implemented by a server to protect passwords of clients, by performing a one-way transformation on the password, turning it into another string called the hashed password. In this paper, we introduce a secure password hashing framework Rig which is based on secure cryptographic hash functions. It provides the flexibility to choose different functions for diff erent phases of the construction. The design of the scheme is very simple to implement in software and is flexible as the memory parameter is independent of time parameter (no actual time and memory trade-o ) and is strictly sequential (difficult to parallelize) with comparatively huge memory consumption that provides strong resistance against attackers using multiple processing units. It supports client-independent updates, i.e., the server can increase the security parameters by updating the existing password hashes without knowing the password. Rig can also support the server relief protocol where the client bears the maximum e ffort to compute the password hash, while there is minimal e ffort at the server side. We analyze Rig and show that our proposal provides an exponential time complexity against the low-memory attack.

Category / Keywords: Password, Password hashing, GPU attack, Cache-timing attack, Client-independent update, Server-relief technique

Original Publication (with minor differences): Inscrypt 2014 Conference

Date: received 6 Jan 2015, last revised 7 Jan 2015

Contact author: swetam at iiitd ac in

Available format(s): PDF | BibTeX Citation

Note: While filling the form there was a typo mistake at the title of the paper. It was showing 'exible' in place of 'flexible'.

Version: 20150107:085502 (All versions of this report)

Short URL: ia.cr/2015/009

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