You need to have recent enough versions of the
shared-mime-info packages installed.
These packages are already installed in Tails.
The needed packages are available starting from:
- Debian version 7 (Wheezy)
- Ubuntu version 15.04 (Vivid)
sudo apt-get update sudo apt-get install seahorse-nautilus/wheezy-backports shared-mime-info/wheezy-backportsIn Debian 8 (Jessie), Ubuntu 15.04 (Vivid), or later, to install the necessary packages, you can execute the following commands:
sudo apt update sudo apt install seahorse-nautilus
If you are unable to install the necessary packages, try verifying the ISO using the command line.
Get the Tails signing key
If you are using Tails, you already have the signing key. Otherwise, first download Tails signing key:
Your browser should propose you to open it with "Import Key". Choose this action. It will add Tails signing key to your keyring, the collection of OpenPGP keys you already imported:
You will get notified will the following message:
The GNOME notifications appear truncated on Tails 1.1 and later.
See ticket #7249.
Verify the ISO image
Now, download the cryptographic signature corresponding to the ISO image you want to verify:
Your browser should propose you to open it with "Verify Signature". Choose this action to start the cryptographic verification:
Browse your files to select the Tails ISO image you want to verify. Then, the verification will start. It can take several minutes:
If the ISO image is correct you will get a notification telling you that the signature is good:
If the ISO image is not correct you will get a notification telling you that the signature is bad: