It was <2020-05-15 pią 00:18>, when Lukasz Stelmach wrote: > It was <2020-05-14 czw 22:20>, when Stephan Mueller wrote: >> Am Donnerstag, 14. Mai 2020, 21:07:33 CEST schrieb Łukasz Stelmach: >> >> Hi Łukasz, >> >>> The value has been estimaded by obtainig 1024 chunks of data 128 bytes >>> (1024 bits) each from the generator and finding chunk with minimal >>> entropy using the ent(1) tool. The value was 6.327820 bits of entropy >>> in each 8 bits of data. >> >> I am not sure we should use the ent tool to define the entropy >> level. Ent seems to use a very coarse entropy estimation. >> >> I would feel more comfortable when using other measures like SP800-90B >> which even provides a tool for the analysis. >> >> I understand that entropy estimates, well, are estimates. But the ent >> data is commonly not very conservative. >> >> [1] https://github.com/usnistgov/SP800-90B_EntropyAssessment [...] > Anyway. I collected 1024 files 1024 bits each once again and ran the > following tests > > for f in exynos-trng/random*; do ./ea_iid "$f" | grep ^min; done | sort | head -1 > for f in rng200/random*; do ./ea_iid "$f" | grep ^min; done | sort | head -1 > > For both RNGs I got the same > > min(H_original, 8 X H_bitstring): 3.393082 Oddly enough I've got the same number for other random sources on my x86 | Source | ea_iid -i | ea_iid -c (h') | ent | |--------------+-----------+----------------+----------| | /dev/random | 3.393082 | 0.768654 | 6.300399 | | /dev/urandom | 3.393082 | 0.759161 | 6.348562 | | tpm-rng | 3.393082 | 0.735722 | 6.323990 | | exynos-trng | 3.393082 | 0.687825 | 6.327820 | | rng200 | 3.393082 | 0.740376 | 6.291959 | I suspect 1024 bits is too little for ea_iid to give a meaningfull result. BTW ent results also seem a little oddly low for crng. Any thoughs? -- Łukasz Stelmach Samsung R&D Institute Poland Samsung Electronics
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