apt-get update


Fetched 396B in 3s (125B/s)
Reading Package Lists... Done
W: GPG error: http://debian.ludost.net testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F1D53D8C4F368D5D
W: GPG error: http://ftp.bg.debian.org. testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F1D53D8C4F368D5D
W: You may want to run apt-get update to correct these problems