I meant not to use the OP_PUSH opcodes to do the push.

Does OP_0 give a zero length byte array?

Would this script return true?

OP_0

OP_PUSHDATA1 (length = 1, data = 0)

OP_EQUAL

The easiest definition is that OP_0 and OP_1 must be used to push the data and not any other push opcodes.

On Fri, Nov 6, 2015 at 9:32 AM, Oleg Andreev <oleganza@gmail.com> wrote:

> One and zero should be defined as arrays of length one. Otherwise, it is still possible to mutate the transaction by changing the length of the array.
>
> They should also be minimally encoded but that is covered by previous rules.

These two lines contradict each other. Minimally-encoded "zero" is an array of length zero, not one. I'd suggest defining this explicitly here as "IF/NOTIF argument must be either zero-length array or a single byte 0x01".