Turns out that Zcash swiched to BLS12-381 since https://github.com/zcash/zcash/issues/2502,
thanks to @EdgeDLT for pointing that out. I've checked that our
TestCubicCircuit_EndToEnd_Prod test passes with response file downloaded
from the attestations page of Zcash ceremony, thus I propose to put theirs
attestations link before the link to PPoT, because PPoT attestations contain
outdated links and not all responses can be downloaded.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
