Changeset - 8cbbc92dd17c
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Laman - 4 years ago 2020-12-18 12:00:38

updated measurements for a new machine
2 files changed with 31 insertions and 4 deletions:
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performance.md
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new file 100644
 
# Performance comparison #
 
## The base case ##
 

	
 
Let's assume we have a secret of length _m_. The splitting takes _n_ evaluations of a polynomial of order _k_ (over Galois field 256) for each byte, leading to _O(n\*k\*m)_ finite field multiplications. Reconstruction of the constant parameters during joining first precomputes parts of the Lagrange polynomial and then reuses them for each byte, taking _O(k\*k + k\*m)_ multiplications.
 

	
 
Benchmark results. The times for split and join mean _seconds per byte_ of the secret length:
 
<table>
 
    <tr>
 
        <th>Revision</th>
 
        <th>Features</th>
 
        <th>k / n parameters</th>
 
        <th>Split</th>
 
        <th>Join</th>
 
    </tr>
 
    <tr>
 
        <td rowspan="2">a47ae3e113cc</td>
 
        <td rowspan="2">-</td>
 
        <td>2 / 3</td>
 
        <td>5.02e-06</td>
 
        <td>4.12e-05</td>
 
    </tr>
 
    <tr>
 
        <td>254 / 254</td>
 
        <td>0.0125</td>
 
        <td>0.00175</td>
 
    </tr>
 
</table>
 
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readme.md
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@@ -23,22 +23,22 @@ Benchmark results, all values mean _seco
 
        <td>2 / 3 (a Raspberry Pi 3)</td>
 
        <td>6.08e-05</td>
 
        <td>0.000435</td>
 
    </tr>
 
    <tr>
 
        <td>2 / 3 (a laptop)</td>
 
        <td>8.7e-06</td>
 
        <td>7.17e-05</td>
 
        <td>5.02e-06</td>
 
        <td>4.12e-05</td>
 
    </tr>
 
    <tr>
 
        <td>254 / 254 (a Raspberry Pi 3)</td>
 
        <td>0.226</td>
 
        <td>0.0314</td>
 
    </tr>
 
    <tr>
 
        <td>254 / 254 (a laptop)</td>
 
        <td>0.0209</td>
 
        <td>0.00347</td>
 
        <td>0.0125</td>
 
        <td>0.00175</td>
 
    </tr>
 
</table>
 

	
 
While the speeds are not awful, for longer secrets I recommend encrypting them with a random key of your choice and splitting only the key. Anyway, you can run your own benchmark with `shamira benchmark`
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