Get:1 http://mirrors.ustc.edu.cn/debian unstable InRelease [158 kB]
Err:1 http://mirrors.ustc.edu.cn/debian unstable InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9
Reading package lists... Done
W: GPG error: http://mirrors.ustc.edu.cn/debian unstable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9
E: The repository 'http://mirrors.ustc.edu.cn/debian unstable InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
`
` benshushu:benshushu# apt update
Get:1 http://mirrors.ustc.edu.cn/debian unstable InRelease [158 kB] Err:1 http://mirrors.ustc.edu.cn/debian unstable InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9 Reading package lists... Done W: GPG error: http://mirrors.ustc.edu.cn/debian unstable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9 E: The repository 'http://mirrors.ustc.edu.cn/debian unstable InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. `