gui-apt-key software package provides Graphical Key Manager for APT, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gui-apt-key
gui-apt-key is installed in your system.
Make ensure the gui-apt-key package were installed using the commands given below,
$ sudo dpkg-query -l | grep gui-apt-key *
You will get with gui-apt-key package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Administration Utilities |
| Package | gui-apt-key |
| Version | 0.4-2ubuntu1 |
| Description | Graphical Key Manager for APT |
| Sub Section | Admin |