The stupid question is the question not asked PerlMonks

### Re^10: SaltedDigest Salt?

by zwon (Abbot)
 on Feb 10, 2012 at 02:38 UTC ( #952904=note: print w/replies, xml ) Need Help??

in reply to Re^9: SaltedDigest Salt?

Do you realize that 9625000 blocks per second ( 616 Mb/s ) is not the same as 2^16?

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Re^11: SaltedDigest Salt?
by BrowserUk (Pope) on Feb 10, 2012 at 04:32 UTC

Of course.

Let me step through it for you again:

1. This pdf shows that FPGAs can be used to perform both DES and SHA512 (and a bunch of others) encryption algorithms.
2. Fig 12. of that pdf shows that SHA512 runs 6 times1 faster than DES.

That experiment used a single FPGA to achieve 91 Mb/s DES.

3. This link shows that the current record holder for performing DES encryption is The COPACOBANA device with a rate of 2^16 Mencryptions/s.
4. I based my projections on the COPACOBANA's DES rate. But as shown, the SHA512 algorithm can be tackled at 6 times that speed.
5. The 2008 version of the COPACOBANA device used 128 Virtex-4 SX 35 FPGAs to achieve that.

These devices have 512 DSP slices running at 500Mhz to produce 250 Giga Multiply-Accumulate/second (GMACS) performance.

6. Now, 4 years later, the hardware has moved on. The latest in that range is the Virtex-7 range.

These devices have 7 times as many DSP slices (3,600) and 20 times2 the peformance (5,335GMACS).

So, going slowly now. SHA512 can be performed 6x faster than DES, and DES has achieved a rate of 2^16Me/s on hardware with 250GMACS. The latest hardware is 20x faster.

So I make that 65536e6 * 61 * 202 = 7.86432e15 SHA512 encryptions/s. Do you concur?

And to bring the story right up to date. The latest hardware, teh RIVYERA can scale to 1796 FPGAs per rack. I'll let you do the math on what its throughput could be.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

Pdf from the point 1 doesn't provide enough information to make any assumptions regarding relative performance of DES and SHA512. The fact that throughput of 3DES running in unspecified mode was 6 times less than throughput of SHA512, doesn't mean anything. 4 is a complete rubbish. In my view you are totally making facts up.
Pdf from the point 1 doesn't provide enough information to make any assumptions regarding relative performance of DES and SHA512.

If you cannot not read a simple graph, then this discussion is pointless.

(Notice also the highlighted text: ... the most secure function, SHA-512, is also the fastest of four investigated hash functions. ")

And nothing is "made up". It is all laid out for you to read for yourself. If you are incapable of doing so despite the lengths I have gone to make it possible for you to verify every single bloody step, then fine. Bury your *&*&\$%\$£^ head in the sand.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

The start of some sanity?

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