Ces clés existent
root@debian:/# apt-key list 9D6D8F6BC857C906
pub rsa4096 2014-11-21 [SC] [expire : 2022-11-19]
D211 6914 1CEC D440 F2EB 8DDA 9D6D 8F6B C857 C906
uid [ inconnue] Debian Security Archive Automatic Signing Key (8/jessie) ftpmaster@debian.org
root@debian:/# apt-key list 8B48AD6246925553
pub rsa4096 2012-04-27 [SC] [expire : 2020-04-25]
A1BD 8E9D 78F7 FE5C 3E65 D8AF 8B48 AD62 4692 5553
uid [ inconnue] Debian Archive Automatic Signing Key (7.0/wheezy) ftpmaster@debian.org
root@debian:/# apt-key list 7638D0442B90D010
pub rsa4096 2014-11-21 [SC] [expire : 2022-11-19]
126C 0D24 BD8A 2942 CC7D F8AC 7638 D044 2B90 D010
uid [ inconnue] Debian Archive Automatic Signing Key (8/jessie) ftpmaster@debian.org
root@debian:/# ls -alrt /etc/apt/trusted.gpg.d
total 48
-rw-r--r-- 1 root root 1813 nov. 14 2012 pkg-mozilla-archive-keyring.gpg
-rw-r--r-- 1 root root 2851 nov. 30 2014 debian-archive-wheezy-stable.gpg
-rw-r--r-- 1 root root 3780 nov. 30 2014 debian-archive-wheezy-automatic.gpg
-rw-r--r-- 1 root root 2853 nov. 30 2014 debian-archive-squeeze-stable.gpg
-rw-r--r-- 1 root root 4084 nov. 30 2014 debian-archive-squeeze-automatic.gpg
-rw-r--r-- 1 root root 2775 nov. 30 2014 debian-archive-jessie-stable.gpg
-rw-r--r-- 1 root root 5147 nov. 30 2014 debian-archive-jessie-security-automatic.gpg
-rw-r--r-- 1 root root 5138 nov. 30 2014 debian-archive-jessie-automatic.gpg
drwxr-xr-x 2 root root 4096 avril 14 2016 .
drwxr-xr-x 6 root root 4096 nov. 17 07:59 ..
peut etre reinstaller le paquet debian-archive-keyring
root@debian:/# apt list debian-archive-keyring -a
En train de lister... Fait
debian-archive-keyring/testing,testing,stable,stable,now 2014.3 all [installé]
root@debian:/#