Pgpkeys: Show WKD-URL of key.

Gemfile

@@ -34,6 +34,10 @@ gem 'jbuilder', '~> 2.5'
 gem 'rqrcode'
 gem 'rotp'
 
+# for pgpkeys
+gem 'base32'
+gem 'gpgme'
+
 gem 'ruby-saml', '~> 1.9.0'
 
 gem 'unidecoder'

Gemfile.lock

@@ -50,6 +50,7 @@ GEM
     ast (2.4.0)
     autoprefixer-rails (9.7.4)
       execjs
+    base32 (0.3.2)
     bindex (0.8.1)
     bootsnap (1.4.4)
       msgpack (~> 1.0)
@@ -91,6 +92,8 @@ GEM
     ffi (1.11.1)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
+    gpgme (2.0.20)
+      mini_portile2 (~> 2.3)
     hashdiff (1.0.0)
     highline (2.0.2)
     http-cookie (1.0.3)
@@ -266,12 +269,13 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  bootsnap (>= 1.1.0)
+  base32
   bootstrap (~> 4.4.1)
   byebug
   capybara (>= 2.15, < 4.0)
   chromedriver-helper
   coffee-rails (~> 4.2)
+  gpgme
   i18n-tasks
   jbuilder (~> 2.5)
   jquery-rails

app/controllers/pgpkeys_controller.rb

 class PgpkeysController < ApplicationController
   def index
     @pgpkey_description = get_key(current_user)
+    @pgpkey_wkd_url = calculate_wkd_url(current_user)
   rescue => exc
     log_exception(exc)
     flash[:verbatim] = exception_to_flash_message(exc)
@@ -68,4 +69,16 @@ class PgpkeysController < ApplicationController
       nil
     end
   end
+
+  def calculate_wkd_url(emailaddress)
+    local_part, domain = emailaddress.split('@', 2)
+    wkd_url_fragment = wkd_hash(local_part)
+    "https://openpgpkey.#{domain}/.well-known/openpgpkey/#{domain}/hu/#{wkd_url_fragment}"
+  end
+
+  def wkd_hash(string)
+    # Table for z-base-32 encoding.
+    Base32.table = "ybndrfg8ejkmcpqxot1uwisza345h769"
+    Base32.encode(Digest::SHA1.digest(string.downcase))
+  end
 end

app/views/pgpkeys/index.html.erb

@@ -10,6 +10,10 @@
       <%= form_tag(pgpkeys_path, method: "delete") do %>
         <b><%= current_user %></b>
         <pre class="pt-2"><%= @pgpkey_description %></pre>
+        <p class='text-secondary'>
+          <%= t('pgpkeys_retrievable_from') %>
+          <span class='text-monospace'><%= @pgpkey_wkd_url %></span>
+        </p>
         <%= submit_tag(t(:delete), class: "btn btn-danger") %>
       <% end %>
     </li>

config/locales/de.yml

@@ -182,6 +182,7 @@ de:
   pgpkeys_upload_key: 'Lade einen neuen oder anderen Schlüssel hoch:'
   pgpkeys_submit_button: Absenden
   pgpkeys_error_message: 'Der Server antwortete: %{error_message}'
+  pgpkeys_retrievable_from: 'Abrufbar unter'
 
   activerecord:
     errors:

config/locales/en.yml

@@ -183,6 +183,7 @@ en:
   pgpkeys_upload_key: 'Upload a new or different key:'
   pgpkeys_submit_button: Send
   pgpkeys_error_message: 'The server responded with: %{error_message}'
+  pgpkeys_retrievable_from: 'Retrievable from'
 
   activerecord:
     errors: