Privacy is a usually included in the larger security landscape, but it deals with aspects that concern people more that technologies and tries to answer a very tough question: “How to access/compute data without the owner know who you are?”. While, like everything, is a sword with two blades, it tries to allow people own their data in the digital world and to provide anonymity while browsing the Internet.

Create the following users: red, green and blue. Make sure that you can ssh into the VM using this users. For example, copy the ”.ssh/” directory from student to the newly added users and “chown” it accordingly.

Pretty Good Privacy (PGP) is an encryption standard that can be used to authenticate in a distributed manner. GNU Privacy Guard (GPG) is an open-source implementation of the PGP standards. In this exercise you are required to send one file encrypted from one user to the other.

For the next exercises, you will need to be logged in as users red/green/blue via ssh in order to generate the gpg key.

• Generate a private/public key using the gpg tool for each of the three users previously created. Don't forget to list all the keys and save their IDs.

• First, we are going to send red's public key to green. Export it into an ASCII file format and import it into green's account.

• Now, green can use red's public key to authenticate him and send an encrypted file. Create a file containing a secret message, encrypt it and send it to the other party.

• Send the encrypted file back to red and decrypt it.

• The next step is to create a trust channel between blue and red using green as a trusted party. To do so, green must firstly sign red's key and export both his key and red's to blue. Move the exported files into blue's directory and import them. After the import was done, list the keys available to blue.

• Now, blue should mark green's key as trusted (by signing it). After this, as the red user, create a file with an important message and sign it (do not encrypt it for this step). Transfer the file to blue, read the file and verify the signature.

• In the default setup mode, the last step should have given a warning stating that the key is not trusted while still being valid (“Good signature”). This is because GPG uses a more complex trusted model. As a last step, login as the blue user and change the trust level for green's key to “I trust ultimately”. After this verify the previous file signature again.

The Tor (The Onion Routing) project is an implementation of the more generic “onion routing” idea that allows a user to gain network anonymity while surfing the Internet. The mechanism that allows for a private surfing is based on re-encryption and “randomly” routing of the packet at the level of each router within the network, allowing each router to only know the previous and the next router in the route (not the source/destination of the packet) ref. Accessing the Tor network can be done either through a local proxy of via a Browser pre-configured with the proxy server.

• The Tor proxy has already been deployed and configured (line 18 & 28 from /etc/tor/torrc) on the virtual machine. Verify that it is listening on an IPv4 port and write it down.

• torsocks is a tool that forces any opened program to use the Tor network for connectivity. Open a shell and find out your real IP address. Now, open a shell using torsocks and find out the IP address via the Tor network. Restart the tor service and discovery your newly allocated IP address.

dig TXT +tcp +short o-o.myaddr.l.google.com @ns1.google.com | awk -F'"' '{ print $2}'

• You are going to configure your local Firefox browser to use the Tor proxy on the VM. First, edit the “Security Group Rules” from OpenStack and make sure that connections to Tor port (via TCP) are allowed. Next, change the Firefox Network Settings to use Socks5 proxy using the IP address and port from your VM. You can verify that your browser is using Tor by accessing the following website.

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