Merge pull request 'ssh-config' (#4) from styan/docs:ssh-config into master

docs/ed25519.md

@@ -42,6 +42,9 @@ Switches:
 When asked to enter a passphrase, do so. An ssh key without a passphrase is
 vulnerable if stolen.
 
+If you want to know how to configure SSH to use a tilde.black specific key
+see [Configuring SSH](ssh-config.md)
+
 ### Keys used in cron-jobs
 
 Some keys may be used for automated scripts and are not appropriate to

docs/ssh-config.md

@@ -0,0 +1,45 @@
+# Configuring SSH
+
+## Setting a Default Username
+
+If your username is different on your tilde than on your personal computer,
+you may want to specify a default username in `~/.ssh/config`.
+That can be done by adding the following entries:
+
+    Host tilde.black
+        User user
+
+## Using a Tilde-Specific key
+
+### Step 1: Generate Your Key
+
+[Generate a key](ed25519.md), except outputting to a Tilde-specific location.
+
+    mkdir -p ~/.ssh/tilde.black
+    ssh-keygen -a100 -ted25519 -f ~/.ssh/tilde.black/id_ed25519 -C ''
+
+### Step 2: Authorize Your Key
+
+If you have yet to [sign up](sign-up.md) to your desired Tilde,
+send the *public* key (`~/.ssh/tilde.black/id_ed25519.pub`) to the admin.
+
+If you already have an account, you can authorize your new key by adding it to,
+or replacing your old key in, `~/.ssh/authorized_keys`.
+
+    $ scp ~/.ssh/tilde.black/id_ed25519.pub user@tilde.black:key.pub
+    $ ssh user@tilde.black
+    tilde$ cat key.pub >> .ssh/authorized_keys
+    tilde$ rm key.pub
+
+### Step 3: Configure SSH
+
+To make `ssh(1)` *only* use that key for that tilde, you can add the following
+lines to `~/.ssh/config`:
+
+    Host tilde.black
+        IdentitiesOnly yes
+        IdentityFile ~/.ssh/tilde.black/id_ed25519
+
+## See Also
+
+[SSH over Tor](ssh-over-tor.md)

docs/ssh-over-tor.md

@@ -111,8 +111,8 @@ onion addresses using the Tor daemon's SOCKS proxy:
     Host *.onion
         ProxyCommand /usr/bin/nc -xlocalhost:9050 -X5 %h %p
 
-Now that `ssh(1)` knows how to connect to onion addresses, a convenient shortcut
-can be added for tilde.black's onion address:
+Now that `ssh(1)` knows how to connect to onion addresses,
+a convenient shortcut can be added for tilde.black's onion address:
 
     Host tilde.black.onion
         HostName black6kfjetfuzaeozz7fs53whh7xtd4e27telrf5fg5kgdt5ah5plad.onion
@@ -123,3 +123,5 @@ With those two additions `ssh(1)` can connect to tilde.black's onion address
 though a much more memorable name:
 
     ssh user@tilde.black.onion
+
+For more information about configuring SSH, see [Configuring SSH](ssh-config.md)

mkdocs.yml

@@ -13,6 +13,7 @@ pages:
   - Anonymity:
     - 'Coming soon': 'anonymity.md'
   - Security:
+    - 'Configuring SSH': 'ssh-config.md'
     - 'Stronger SSH Keys': 'ed25519.md'
 theme:
   name: material