diff --git a/irctest/__main__.py b/irctest/__main__.py
index 67f64d9..18f3ed4 100644
--- a/irctest/__main__.py
+++ b/irctest/__main__.py
@@ -28,6 +28,7 @@ def main(args):
                 file=sys.stderr)
         exit(1)
     _IrcTestCase.controllerClass = controller_class
+    _IrcTestCase.controllerClass.openssl_bin = args.openssl_bin
     _IrcTestCase.show_io = args.show_io
     _IrcTestCase.strictTests = not args.loose
     if args.specification:
@@ -63,6 +64,8 @@ parser = argparse.ArgumentParser(
         description='A script to test interoperability of IRC software.')
 parser.add_argument('module', type=str,
         help='The module used to run the tested program.')
+parser.add_argument('--openssl-bin', type=str, default='openssl',
+        help='The openssl binary to use')
 parser.add_argument('--show-io', action='store_true',
         help='Show input/outputs with the tested program.')
 parser.add_argument('-v', '--verbose', action='count', default=1,
diff --git a/irctest/basecontrollers.py b/irctest/basecontrollers.py
index 7ccf00d..974bc23 100644
--- a/irctest/basecontrollers.py
+++ b/irctest/basecontrollers.py
@@ -56,15 +56,15 @@ class DirectoryBasedController(_BaseController):
         self.key_path = os.path.join(self.directory, 'ssl.key')
         self.pem_path = os.path.join(self.directory, 'ssl.pem')
         self.dh_path = os.path.join(self.directory, 'dh.pem')
-        subprocess.check_output(['openssl', 'req', '-new', '-newkey', 'rsa',
+        subprocess.check_output([self.openssl_bin, 'req', '-new', '-newkey', 'rsa',
             '-nodes', '-out', self.csr_path, '-keyout', self.key_path,
             '-batch'],
             stderr=subprocess.DEVNULL)
-        subprocess.check_output(['openssl', 'x509', '-req',
+        subprocess.check_output([self.openssl_bin, 'x509', '-req',
             '-in', self.csr_path, '-signkey', self.key_path,
             '-out', self.pem_path],
             stderr=subprocess.DEVNULL)
-        subprocess.check_output(['openssl', 'dhparam',
+        subprocess.check_output([self.openssl_bin, 'dhparam',
             '-out', self.dh_path, '128'],
             stderr=subprocess.DEVNULL)
 
@@ -80,7 +80,7 @@ class BaseServerController(_BaseController):
             valid_metadata_keys, invalid_metadata_keys):
         raise NotImplementedError()
     def registerUser(self, case, username, password=None):
-        raise NotImplementedByController('registration')
+        raise NotImplementedByController('account registration')
     def wait_for_port(self):
         while not self.port_open:
             time.sleep(0.1)