diff --git a/pagure/utils.py b/pagure/utils.py
index a875c1f..3d71822 100644
--- a/pagure/utils.py
+++ b/pagure/utils.py
@@ -632,3 +632,28 @@ def get_merge_options(request, merge_status):
             merge_status += "-non-ff-ok"
 
     return MERGE_OPTIONS[merge_status]
+
+
+def lookup_deploykey(project, username):
+    """ Finds the Deploy Key specified by the username.
+
+    Args:
+        project (model.Project): The project to look in
+        username (string): The username string provided for the deploy key
+    Returns (model.SSHKey or None): The SSHKey instance representing the
+        project-specific deploy key by the username. None if the username is
+        not a deploykey username or is not a valid deploy key for project.
+    """
+    # The username to look for is: deploykey_(filename(project.fullname))_keyid
+    if not username.startswith("deploykey_"):
+        return None
+    username = username[len("deploykey_") :]
+    rest, keyid = username.rsplit("_", 1)
+    if rest != werkzeug.secure_filename(project.fullname):
+        # This is not a deploykey for the specified project
+        return None
+    keyid = int(keyid)
+    for key in project.deploykeys:
+        if key.id == keyid:
+            return key
+    return None
diff --git a/tests/test_pagure_utils.py b/tests/test_pagure_utils.py
new file mode 100644
index 0000000..5150f95
--- /dev/null
+++ b/tests/test_pagure_utils.py
@@ -0,0 +1,83 @@
+# -*- coding: utf-8 -*-
+
+"""
+ (c) 2018 - Copyright Red Hat Inc
+
+ Authors:
+   Patrick Uiterwijk <puiterwijk@redhat.com>
+
+"""
+
+from __future__ import unicode_literals
+
+__requires__ = ['SQLAlchemy >= 0.8']
+import pkg_resources
+
+import unittest
+import shutil
+import sys
+import os
+
+import mock
+import munch
+import pygit2
+import werkzeug
+
+sys.path.insert(0, os.path.join(os.path.dirname(
+    os.path.abspath(__file__)), '..'))
+
+import pagure.lib
+import pagure.lib.model
+import pagure.utils
+import tests
+
+
+class PagureUtilsTests(tests.SimplePagureTest):
+    """ Tests for pagure.utils """
+
+    def setUp(self):
+        """ Set up the environnment, run before every tests. """
+        super(PagureUtilsTests, self).setUp()
+
+        tests.create_projects(self.session)
+        tests.create_projects_git(os.path.join(self.path, 'repos'), bare=True)
+        tests.add_content_git_repo(os.path.join(self.path, 'repos', 'test2.git'))
+
+        project = pagure.lib._get_project(self.session, 'test')
+        # Add a deploy key to the project
+        new_key_obj = pagure.lib.model.SSHKey(
+            project_id=project.id,
+            pushaccess=False,
+            public_ssh_key='\n foo bar',
+            ssh_short_key='\n foo bar',
+            ssh_search_key='\n foo bar',
+            creator_user_id=1  # pingou
+        )
+
+        self.session.add(new_key_obj)
+        self.session.commit()
+
+    def test_lookup_deploykey_non_deploykey(self):
+        """ Test lookup_deploykey with a non-deploykey username. """
+        project = pagure.lib._get_project(self.session, 'test')
+        res = pagure.utils.lookup_deploykey(project, 'pingou')
+        self.assertEquals(res, None)
+
+    def test_lookup_deploykey_different_project(self):
+        """ Test lookup_deploykey with a username for another project. """
+        project = pagure.lib._get_project(self.session, 'test2')
+        res = pagure.utils.lookup_deploykey(project, 'deploykey_test_1')
+        self.assertEquals(res, None)
+
+    def test_lookup_deploykey_non_existent_key(self):
+        """ Test lookup_deploykey with a non-existing deploykey. """
+        project = pagure.lib._get_project(self.session, 'test')
+        res = pagure.utils.lookup_deploykey(project, 'deploykey_test_2')
+        self.assertEquals(res, None)
+
+    def test_lookup_deploykey(self):
+        """ Test lookup_deploykey with a correct username. """
+        project = pagure.lib._get_project(self.session, 'test')
+        res = pagure.utils.lookup_deploykey(project, 'deploykey_test_1')
+        self.assertNotEquals(res, None)
+        self.assertFalse(res.pushaccess)