This Ki is never transmitted between the AuC and SIM, but is combined with the IMSI to produce a challenge/response for identification purposes and an encryption key called Kc for use in over the air communications.
这个Ki从不会被在AuC和SIM之间传输，但是会被关联到IMSI来产生一个挑战/响应（challenge/response）用于身份识别，以及一个被称为“Kc”的密钥（encryption key）来在空中通信上使用（air communications）。