我尝试在 ubuntu 12.04 LTS 上添加 debian sid 源。我已经安装了 debian-keyring debian-archive-keyring。
$ apt-cache search keyring | grep debian
debian-archive-keyring - GnuPG archive keys of the Debian archive
debian-keyring - GnuPG keys of Debian Developers
debian-ports-archive-keyring - GnuPG archive keys of the debian-ports archive
emdebian-archive-keyring - GnuPG archive keys for the emdebian repository
但是，它仍然说缺少一个密钥：7638D0442B90D010。我错过了什么？
#apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 7638D0442B90D010
Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /tmp/tmp.xxxxx --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyring /etc/apt/trusted.gpg.d//debian-archive-squeeze-automatic.gpg --keyring /etc/apt/trusted.gpg.d//debian-archive-squeeze-stable.gpg --keyring /etc/apt/trusted.gpg.d//debian-archive-wheezy-automatic.gpg --keyring /etc/apt/trusted.gpg.d//debian-archive-wheezy-stable.gpg --keyserver keyserver.ubuntu.com --recv-keys 7638D0442B90D010
gpg: requesting key 2B90D010 from hkp server keyserver.ubuntu.com
gpg: key 2B90D010: public key "Debian Archive Automatic Signing Key (8/jessie) <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
看来我只有 debian squeeze 和 wheezy 密钥。我该如何为 sid 安装密钥环？