debian 5 apt出现no public key available for the f...

换了163的源结果出现

W: There is no public key available for the following key IDs:
9AA38DCD55BE302B
W: GPG error: http://mirrors.163.com lenny-proposed-updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY AED4B06F473041FA
W: GPG error: http://mirrors.163.com lenny/updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 9AA38DCD55BE302B
W: You may want to run apt-get update to correct these problems

于是乎google

解决的办法为:
apt-get install debian-keyring debian-archive-keyring
然后
apt-key update

搞定！