diff --git a/paramiko/ecdsakey.py b/paramiko/ecdsakey.py
index bb5b780..23bf0fe 100644
--- a/paramiko/ecdsakey.py
+++ b/paramiko/ecdsakey.py
@@ -102,8 +102,7 @@ class ECDSAKey (PKey):
 
     def sign_ssh_data(self, data):
         digest = SHA256.new(data).digest()
-        sig = self.signing_key.sign_digest(digest, entropy=os.urandom,
-                                           sigencode=self._sigencode)
+        sig = self.signing_key.sign_digest(digest, sigencode=self._sigencode)
         m = Message()
         m.add_string('ecdsa-sha2-nistp256')
         m.add_string(sig)