Same issue
$ lsb_release -r Release: 14.04 $ uname -r 3.13.0-52-generic
May 10 00:40:40 kernel: [...] Request for unknown module key 'Magrathea: Glacier signing key: 1981bc916ffc00599231ec5630e666e0256fd6f1' err -11 May 10 00:40:40 kernel: [...] ipt_REJECT: module verification failed: signature and/or required key missing - tainting kernel
Same issue
$ lsb_release -r
Release: 14.04
$ uname -r
3.13.0-52-generic
May 10 00:40:40 kernel: [...] Request for unknown module key 'Magrathea: Glacier signing key: 1981bc916ffc005 99231ec5630e666 e0256fd6f1' err -11
May 10 00:40:40 kernel: [...] ipt_REJECT: module verification failed: signature and/or required key missing - tainting kernel