Paper 2015/009

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

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


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 different 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-off) 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 effort to compute the password hash, while there is minimal effort at the server side. We analyze Rig and show that our proposal provides an exponential time complexity against the low-memory attack.

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

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Publication info
Published elsewhere. Minor revision. Inscrypt 2014 Conference
PasswordPassword hashingGPU attackCache-timing attackClient-independent updateServer-relief technique
Contact author(s)
swetam @ iiitd ac in
2015-01-07: revised
2015-01-07: received
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Creative Commons Attribution


      author = {Donghoon Chang and Arpan Jati and Sweta Mishra and Somitra Kumar Sanadhya},
      title = {Rig: A simple, secure and flexible design for Password Hashing},
      howpublished = {Cryptology ePrint Archive, Paper 2015/009},
      year = {2015},
      note = {\url{}},
      url = {}
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