W: GPG error: http://ftp.us.debian.org testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A70DAF536070D3A1
W: GPG error: http://security.debian.org etch/updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A70DAF536070D3A1
W: GPG error: http://security.debian.org testing/updates Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A70DAF536070D3A1