[操作疑難] Synology encrypted backup

好耐之前玩過一次. 但發現佢up上去既file名係一樣, 我又唔知佢有冇encrypt (太大中途已經abort左)
當我真係全部encrypt upload左上去, 我rebuild 再mount 返, 我都真係唔知佢點自動decrypt. 定係encrypt 再encrypt. 有啲頭痕...

有冇人可以解釋一下?