Spoken, they would sound like 鍵を and 詐欺を.
I once heard about a very nervous young Japanese man on a high pressure job interview who in response to 「かぎょうをいってください」 replied 「かきくけこ」which resulted first in puzzled looks and then gales of laughter from the panel interviewing him.
Difference of か行 and 家業, you see.
Come to think of it, さぎょう is a word I use a lot, but it is 作業 and not さ行.