We intercepted this encrypted message. What is the key?
Intercepted Message
Gmrpiz dlc jopi sd bhq dezclm biaba, qkgf ilbrezmt uc wfqffoh mve xoxrmr fy xfm lqpx dzoy dlc wnq kfmde ud. Xfqs ryvka 26 ragw mn stsjrmd mvtfibqdw, cvduxk uqtt kr ytptkfcb sfkvrqns gmrp Z (mc wfwwz sr guaso). Wcxadkxc nraw xfmsq 26 kpnpanoxq irq k lcidqb vme af dlc bob krb i hqkhcz cavykv oz dlc terd, iykh oyrriizsre bhq virbedc sd bhq kpnpanox gv A-L yvbmr.