; now xor with polynomial if tmp degree too high
			; this means timing analysis will leak polynomial info
			; however, this is a public spec and therefore not
			; implementation-breaking
			bit 1, (ix - 4)		; polynomial is 233 bits, check 234th bit
			jr z, .no_xor_poly

			; xor byte 1 (little-endian encoding)
			ld a, (ix - 32 + 1)
			xor 2
			ld (ix - 32 + 1), a

			; xor byte 21 (little endian encoding)
			ld a, (ix - 32 + 21)
			xor 4
			ld (ix - 32 + 21), a

			; xor byte 28
			ld a, (ix - 32 + 28)
			xor 1
			ld (ix - 32 + 28), a




.no_xor_poly