The drawback of the right-to-left generation of wNAF is that it is not possible to merge the exponent recoding and the left-to-right evaluation stage,and additional storage is required.
目前最著名的带符号的表示方法是wNAF(non-adjacent-form),不幸的是wNAF编码只能从右向左产生,这使得编码阶段不能和较具优势的从左向右的计算阶段相结合形成有效的计算方法。