> When someone had your password, it's not just that they could access any information, but that they could become you.
https://www.wired.com/2012/07/people-staring-at-computers/ 

 秘密鍵それ自体が正当性の担保だから、このnostrだとこれが誇張ではなく本当に文字通り become you になるんだなー
自己同一性をユーザ自身ではなく数十字の文字列に一任させてる