diff --git a/README.md b/README.md
index 8f43c9a..db66c7d 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 `kelunik/acme-client` is a standalone ACME client written in PHP.
 It's an alternative for the [official client](https://github.com/letsencrypt/letsencrypt) which is written in python.
 
-> **Warning**: This software is under heavy development. Use at your own risk. Revocation is not yet supported by this client.
+> **Warning**: This software is under heavy development. Use at your own risk.
 
 ## Installation
 
@@ -18,6 +18,9 @@ composer install
 
 ## Usage
 
+> **Note**: This client stores all data in `./data`, be sure to backup this folder regularly.
+> It contains your account keys, domain keys and certificates.
+
 Before you can issue certificates, you have to register an account first and read and understand the terms of service of the ACME CA you're using.
 For Let's Encrypt there's a [subscriber agreement](https://letsencrypt.org/repository/) you have to accept.
 
@@ -41,4 +44,12 @@ sudo bin/acme issue \
     --path /var/www/example.com
 ```
 
-For renewal, just run this command again.
\ No newline at end of file
+For renewal, just run this command again.
+
+To revoke a certificate, you need a valid account key currently, just like for issuance.
+
+```
+sudo bin/acme revoke \
+    --server acme-v01.api.letsencrypt.org/directory \
+    --cert data/live/example.com/cert.pem
+```
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 04ed83d..3809941 100644
--- a/composer.json
+++ b/composer.json
@@ -5,9 +5,9 @@
         "php": ">=7.0.0",
         "ext-posix": "*",
         "ext-openssl": "*",
-        "amphp/aerys": "dev-master",
         "bramus/monolog-colored-line-formatter": "^2",
         "kelunik/acme": "dev-master",
+        "kelunik/certificate": "dev-master",
         "league/climate": "^3",
         "monolog/monolog": "^1.17",
         "psr/log": "^1",
diff --git a/src/Commands/Revoke.php b/src/Commands/Revoke.php
index 144ffeb..6927a66 100644
--- a/src/Commands/Revoke.php
+++ b/src/Commands/Revoke.php
@@ -3,20 +3,97 @@
 namespace Kelunik\AcmeClient\Commands;
 
 use Amp\Promise;
+use Generator;
+use Kelunik\Acme\AcmeClient;
 use Kelunik\Acme\AcmeException;
+use Kelunik\Acme\AcmeService;
+use Kelunik\Acme\KeyPair;
+use Kelunik\Certificate\Certificate;
 use League\CLImate\Argument\Manager;
+use Psr\Log\LoggerInterface;
+use function Amp\File\exists;
+use function Amp\File\get;
+use function Amp\resolve;
 
 class Revoke implements Command {
+    private $logger;
+
+    public function __construct(LoggerInterface $logger) {
+        $this->logger = $logger;
+    }
+
     public function execute(Manager $args): Promise {
-        throw new AcmeException("Command not yet implemented!");
+        return resolve($this->doExecute($args));
+    }
+
+    private function doExecute(Manager $args): Generator {
+        if (posix_geteuid() !== 0) {
+            throw new AcmeException("Please run this script as root!");
+        }
+
+        $server = $args->get("server");
+        $protocol = substr($server, 0, strpos("://", $server));
+
+        if (!$protocol || $protocol === $server) {
+            $server = "https://" . $server;
+        } elseif ($protocol !== "https") {
+            throw new \InvalidArgumentException("Invalid server protocol, only HTTPS supported");
+        }
+
+        $keyPair = $this->checkRegistration($args);
+        $acme = new AcmeService(new AcmeClient($server, $keyPair), $keyPair);
+
+        $this->logger->info("Revoking certificate ...");
+
+        $pem = yield get($args->get("cert"));
+        $cert = new Certificate($pem);
+
+        if ($cert->getValidTo() < time()) {
+            $this->logger->warning("Certificate did already expire, no need to revoke it.");
+            return;
+        }
+
+        $this->logger->info("Certificate was valid for: " . implode(", ", $cert->getNames()));
+
+        yield $acme->revokeCertificate($pem);
+
+        $this->logger->info("Certificate has been revoked.");
+    }
+
+    private function checkRegistration(Manager $args) {
+        $server = $args->get("server");
+        $protocol = substr($server, 0, strpos("://", $server));
+
+        if (!$protocol || $protocol === $server) {
+            $server = "https://" . $server;
+        } elseif ($protocol !== "https") {
+            throw new \InvalidArgumentException("Invalid server protocol, only HTTPS supported");
+        }
+
+        $identity = str_replace(["/", "%"], "-", substr($server, 8));
+
+        $path = __DIR__ . "/../../data/accounts";
+        $pathPrivate = "{$path}/{$identity}.private.key";
+        $pathPublic = "{$path}/{$identity}.public.key";
+
+        if (file_exists($pathPrivate) && file_exists($pathPublic)) {
+            $private = file_get_contents($pathPrivate);
+            $public = file_get_contents($pathPublic);
+
+            $this->logger->info("Found account keys.");
+
+            return new KeyPair($private, $public);
+        }
+
+        throw new AcmeException("No registration found for server, please register first");
     }
 
     public static function getDefinition(): array {
         return [
-            "domains" => [
-                "prefix" => "d",
-                "longPrefix" => "domains",
-                "description" => "Domains to request a certificate for.",
+            "cert" => [
+                "prefix" => "c",
+                "longPrefix" => "cert",
+                "description" => "Certificate to be revoked.",
                 "required" => true,
             ],
             "server" => [