possible bug
@@ -85,5 +85,6 @@ def check_ssasig(ssasig: Signature) -> bool:
"ssasig must be a tuple of 2 int"
# TODO: maybe new ec.is_x_valid(x) method
ec.yOdd(ssasig[0], False) # R.x is valid iif R.y does exist
+ # FIXME: it might be 0 <= ssasig[1]
assert 0 < ssasig[1] and ssasig[1] < ec.order, "s must be in [1..order]"
return True
