Should the number of zeros chosen to be positive or just non-negative?

[dannyniu]

In the current draft (as of this writing), the each amendments to the existing RFCs contain:

the number of zeroes 000... is chosen so that the length are multiples of ...

Should this number chosen to be strictly positive? Or a length of 0 is also acceptable?

[FiloSottile]

I had the same doubt. FWIW I chose to interpret a length of zero to be acceptable, since it still achieves its stated purpose without wasting a whole hash compression on zeroes.

Would be good to clarify.