[Cryptography] Dieharder & symmetric cryptosystems

Ray Dillinger bear at sonic.net
Wed Mar 16 12:41:19 EDT 2022



On 3/14/22 23:24, Ray Dillinger wrote:
> If WEAK results on a particular test are persistent across several
> different runs and regardless of whether we increase the sample size,
> then that's something that has to be fixed.

Grrrrf.  Normally Thunderbird's penchant for adding newline characters
at points where they don't appear as you're editing text isn't a
problem because I'm sending text that is language formatted in
paragraphs. When I'm sending text that is data formatted in columns,
however, that "helpfully" makes hash of it.  So I'm resending,
edited strictly into <70-column lines.

I have found a genuine problem here but first, I don't think it's the
same one that OP intended to report, and second, I assess it as a
problem with Dieharder not a problem with /dev/urandom.  I've pasted a
repeated test (specifically test 201, the 'rgb_minimum_distance' test)
against /dev/urandom input.  As you can see, '/dev/urandom' fails every
time.

But note that the p-value assessment is 0.0000, which means dieharder
is seeing a series of numbers which it thinks have ABSOLUTELY no chance
of coming from a random generator.  Also of note, this particular test
is now failing, with p-value assessment of 0.0000, on EVERY generator
in the dieharder suite.

This indicates to me that there is some problem in the way this
particular test is implemented, entirely separate from any problem with
/dev/urandom.

                        Bear


------------Paste (edited for 70-col width) follows----------------
$ cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1;
  cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1;
  cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1;
  cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1;
  cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1;
  cat /dev/urandom | dieharder -g200 -d201 -k2 -Y1

#==================================================================#
#    dieharder version 3.31.1 Copyright 2003 Robert G. Brown       #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  3.41e+07  |3141542943|
#==================================================================#
   test_name   |ntup| tsamples |psamples|  p-value |Assessment
#==================================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED  


#==================================================================#
#   dieharder version 3.31.1 Copyright 2003 Robert G.Brown        #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  3.64e+07  |1726740133|
#==================================================================#
        test_name   |ntup| tsamples |psamples|  p-value |Assessment
#==================================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED  

#==================================================================#
#   dieharder version 3.31.1 Copyright 2003 Robert G.Brown        #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  3.52e+07  |3912038150|
#==================================================================#
        test_name   |ntup| tsamples |psamples|  p-value |Assessment
#=================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED  

#==================================================================#
#   dieharder version 3.31.1 Copyright 2003 Robert G.Brown        #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  4.22e+07  |1020210298|
#==================================================================#
        test_name   |ntup| tsamples |psamples|  p-value |Assessment
#=================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED  

#==================================================================#
#   dieharder version 3.31.1 Copyright 2003 Robert G.Brown        #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  4.35e+07  | 749211463|
#==================================================================#
        test_name   |ntup| tsamples |psamples|  p-value |Assessment
#==================================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED  

#==================================================================#
#   dieharder version 3.31.1 Copyright 2003 Robert G.Brown        #
#==================================================================#
   rng_name    |rands/second|   Seed   |
stdin_input_raw|  4.16e+07  |4293996729|
#==================================================================#
        test_name   |ntup| tsamples |psamples|  p-value |Assessment
#==================================================================#
rgb_minimum_distance|   0|     10000|    1000|0.00000000|  FAILED 
$



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