Hello, all! I was asked by Zooko to post the results from the project done by my colleague and I this autumn, which was trying out the (then) 14 candidates of the NIST SHA-3 competition with Tahoe-LAFS.
Unfortunately, the project did not end up with code submitted to the Tahoe repository. We wanted to create a way to easily change underlying hash algorithm, maybe in the form of new capabilities, but we were limited by time as we had to write Python bindings for a numerous amount of different implementations for the SHA-3 candidates. The resulting paper [0] is approx. 60 pages long, so I will try to sum up what I think is relevant: ---------------------------------------------------------------------------- - From «Abstract»: In general, four of the candidates perform better than the currently used SHA-256 - BLAKE, BlueMidnightWish, Shabal and Simd. By utilizing the performance improvements given by SHA-3, we show that Tahoe-LAFS could currently save up to 12.36% on upload operations by changing to the best performing candidate. Comment: This should increase when better optimizations are created, and the focus is on one, final algorithm, i.e. the «winner». - From 3.3 «Modifications to the Tahoe-LAFS Code»: ... only immutable files are tested and measured in this paper. From 3.5 «Configuration of Test Environment»: Four machines was used as a testing grid, each containing an Intel(R) Core(TM)2 Duo E8300 CPU and 4GB of RAM. The 32-bit version of Ubuntu Linux Server Edition 10.04 was the operating system of choice. Comment: Tahoe-LAFS was set up to 2/3/3 (shares needed/happy/available). - Section 3.4 «Measuring Performance»: Describes how and where we timed the different calls, i.e. within util.hashutil and with Bash scripts. - Section 4.4 «Measurements of internal Tahoe hashing sizes»: Displays the distribution of data chunk sizes while uploading the test vectors. The test vectors are listed in Section 3.5.1. - Tables 4.4 to 4.13: (Probably most useful.) Lists total time, time spent hashing, fraction (time spent hashing / total time) for each of the test vectors for both upload and download, for each of the different SHA-3 candidates. These numbers are also illustrated in the following graphs. ---------------------------------------------------------------------------- We hope that someone finds this small contribution useful somehow. [0] http://folk.ntnu.no/palru/project.pdf Best regards, -- Pål Ruud and Eirik Haver, Department of Telematics, Norwegian University of Science and Technology _______________________________________________ tahoe-dev mailing list [email protected] http://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev
