1 files changed, 13 insertions, 1 deletions
diff --git a/memoryhole/openpgp.py b/memoryhole/openpgp.py
index 3cefc3c..3318704 100644
--- a/memoryhole/openpgp.py
+++ b/memoryhole/openpgp.py
@@ -2,7 +2,7 @@ from zope.interface import Interface
 
 
 class IOpenPGP(Interface):
-    def encrypt(data, encraddr, singaddr):
+    def encrypt(data, encraddr):
         """
         Encrypt and sign data.
 
@@ -18,6 +18,18 @@ class IOpenPGP(Interface):
         """
         pass
 
+    def sign(data):
+        """
+        Sign data.
+
+        :param data: data to be encrypted
+        :type data: str
+
+        :return: signature
+        :rtype: str
+        """
+        pass
+
     def decrypt(data):
         """
         Decrypt and verify data.