我有一个Debian Squeeze EC2 AMI。 在启动一个实例并试图用apt-get安装软件包时，我收到错误，说没有安装密钥环。 这是apt-get update的错误：
root@ip:~# apt-get update Get:1 http://ftp.us.debian.org squeeze Release.gpg [1672 B] Ign http://ftp.us.debian.org/debian/ squeeze/contrib Translation-en Ign http://ftp.us.debian.org/debian/ squeeze/main Translation-en Ign http://ftp.us.debian.org/debian/ squeeze/non-free Translation-en Get:2 http://security.debian.org squeeze/updates Release.gpg [836 B] Ign http://security.debian.org/ squeeze/updates/contrib Translation-en Ign http://security.debian.org/ squeeze/updates/main Translation-en Hit http://ftp.us.debian.org squeeze Release Ign http://ftp.us.debian.org squeeze Release Ign http://security.debian.org/ squeeze/updates/non-free Translation-en Ign http://ftp.us.debian.org squeeze/main Sources/DiffIndex Get:3 http://security.debian.org squeeze/updates Release [86.9 kB] Ign http://security.debian.org squeeze/updates Release Ign http://ftp.us.debian.org squeeze/contrib Sources/DiffIndex Ign http://ftp.us.debian.org squeeze/non-free Sources/DiffIndex Ign http://ftp.us.debian.org squeeze/main amd64 Packages/DiffIndex Ign http://ftp.us.debian.org squeeze/contrib amd64 Packages/DiffIndex Ign http://ftp.us.debian.org squeeze/non-free amd64 Packages/DiffIndex Ign http://security.debian.org squeeze/updates/main Sources/DiffIndex Hit http://ftp.us.debian.org squeeze/main Sources Hit http://ftp.us.debian.org squeeze/contrib Sources Hit http://ftp.us.debian.org squeeze/non-free Sources Hit http://ftp.us.debian.org squeeze/main amd64 Packages Hit http://ftp.us.debian.org squeeze/contrib amd64 Packages Ign http://security.debian.org squeeze/updates/contrib Sources/DiffIndex Ign http://security.debian.org squeeze/updates/non-free Sources/DiffIndex Ign http://security.debian.org squeeze/updates/main amd64 Packages/DiffIndex Ign http://security.debian.org squeeze/updates/contrib amd64 Packages/DiffIndex Ign http://security.debian.org squeeze/updates/non-free amd64 Packages/DiffIndex Hit http://ftp.us.debian.org squeeze/non-free amd64 Packages Get:4 http://backports.debian.org squeeze-backports Release.gpg [836 B] Ign http://backports.debian.org/debian-backports/ squeeze-backports/main Translation-en Hit http://security.debian.org squeeze/updates/main Sources Hit http://security.debian.org squeeze/updates/contrib Sources Hit http://security.debian.org squeeze/updates/non-free Sources Hit http://security.debian.org squeeze/updates/main amd64 Packages Hit http://security.debian.org squeeze/updates/contrib amd64 Packages Hit http://security.debian.org squeeze/updates/non-free amd64 Packages Get:5 http://backports.debian.org squeeze-backports Release [77.6 kB] Ign http://backports.debian.org squeeze-backports Release Hit http://backports.debian.org squeeze-backports/main amd64 Packages/DiffIndex Hit http://backports.debian.org squeeze-backports/main amd64 Packages Fetched 3346 B in 0s (5298 B/s) Reading package lists... Done W: GPG error: http://ftp.us.debian.org squeeze Release: No keyring installed in /etc/apt/trusted.gpg.d/. W: GPG error: http://security.debian.org squeeze/updates Release: No keyring installed in /etc/apt/trusted.gpg.d/. W: GPG error: http://backports.debian.org squeeze-backports Release: No keyring installed in /etc/apt/trusted.gpg.d/. 谷歌search并没有真正帮助我解决这个问题。 我试过安装软件包“debian-keyring”和“debian-archive-keyring”，但是错误并没有消失。 我想避免安装不受信任的软件包。 任何帮助表示赞赏！ 为什么会发生这种错误，我可以在哪里学到更多？
最后解决这个问题：
wget --no-check-certificate https://ftp-master.debian.org/keys/archive-key-6.0.asc && apt-key add archive-key-6.0.asc apt-get update apt-get install --reinstall debian-keyring debian-archive-keyring apt-get update