Create a Tor Hidden Service

A simple example of creating and using a Tor Hidden Service.

Using SSH as an example, use any other name to be change the directory name.

Install Tor:
```
sudo apt install tor
```
Edit the config file:
```
sudo nano /etc/tor/torrc
```
Create a v3 onion address
sharing the internal ssh port (22) on the custom port 8080 of the .onion service:
```
HiddenServiceDir /var/lib/tor/ssh/
HiddenServiceVersion 3
HiddenServicePort 8080 127.0.0.1:22
```
Restart Tor:
```
sudo systemctl restart tor
```

List the files in the directory

$ sudo ls -la /var/lib/tor/ssh/
total 12
drwx------ 1 debian-tor debian-tor 136 Jan 30 07:09 .
drwx------ 1 debian-tor debian-tor 826 Jan 31 00:00 ..
drwx------ 1 debian-tor debian-tor   0 Feb 11  2020 authorized_clients
-rw------- 1 debian-tor debian-tor  63 Jan 30 07:09 hostname
-rwx------ 1 debian-tor debian-tor  64 Feb 11  2020 hs_ed25519_public_key
-rwx------ 1 debian-tor debian-tor  96 Feb 11  2020 hs_ed25519_secret_key

Note the Hidden Service address:
```
sudo cat /var/lib/tor/ssh/hostname
```
For ssh over Tor install Tor on your client
- Linux:
```
sudo apt install tor
```
- On mobile can use Termux:
```
pkg install tor
```
  run Tor in a different window:
```
tor
```
  or in the background with:
```
tor &
```
- See this video for different Windows and MacOS: https://www.keepitsimplebitcoin.com/how-to-install-tor/
SSH over Tor
in a Linux terminal use (set the custom port used for ssh):
```
torify ssh username@HiddenServiceAddress.onion:8080
```
If there is a website hosted on your .onion service use the Tor Browser to open the address.

Add client authorization (Optional)

A simple example of requiring authentication credential in order to connect to the onion service

Install required packages:
```
sudo apt install basez openssl
```

Generate key:

openssl genpkey -algorithm x25519 -out /tmp/k1.prv.pem

Re-format key into base32 creating public and private keys:

cat /tmp/k1.prv.pem | grep -v " PRIVATE KEY" | base64pem -d | tail --bytes=32 | base32 | sed 's/=//g' > /tmp/k1.prv.key
openssl pkey -in /tmp/k1.prv.pem -pubout | grep -v " PUBLIC KEY" | base64pem -d | tail --bytes=32 | base32 | sed 's/=//g' > /tmp/k1.pub.key

Note the private key (client):
```
cat /tmp/k1.prv.key
```
Note the public key: (server):
```
cat /tmp/k1.pub.key
```

Server config:

Create .auth file:

 sudo nano /var/lib/tor/ssh/authorized_clients/alice.auth

Edit .auth file:
```
 descriptor:x25519:<base32-pub-key>
```

Client config for (choose one):
- GUI service (thunderhub):
  - Enter the private key noted above Tor Browser when prompted the credential window.
- Headless service (ssh):
  - Edit the config file:
    ClientOnionAuthDir /var/lib/tor/onion_auth/
  - Create .auth_private file:
    sudo nano /var/lib/tor/onion_auth/bob-ssh.auth_private
  - Edit .auth_private file
    <56-char-onion-addr-without-.onion-part>:descriptor:x25519:<base32-priv-key>

Remove keys stored in /tmp:

sudo rm -f /tmp/k1.pub.key /tmp/k1.prv.key /tmp/k1.prv.pem

Restart Tor to apply changes (server and client):
```
sudo systemctl restart tor@default
```

Notes:

The SSL stripping attack is not applicable when the traffic does not leave the Tor network so usinga self-hosted Hidden Service in the Tor Browser is not at risk.
Always make sure that the clearnet site you open in the Tor Browser uses SSL encryption (HTTPS).

Create a Tor Hidden Service

Add client authorization (Optional)

Notes:

Sources: