diff --git a/source/app/controllers/pacs/cfdi_cert.py b/source/app/controllers/pacs/cfdi_cert.py
index 210ec53..185bca2 100644
--- a/source/app/controllers/pacs/cfdi_cert.py
+++ b/source/app/controllers/pacs/cfdi_cert.py
@@ -31,12 +31,12 @@ class SATCertificate(object):
         self._test()
 
     def _test(self):
-        self._p = self._get_hash()
         key = self._get_key('')
+        self._p = f"{self.rfc}|{self.serial_number}"
         self._key_der = key.private_bytes(
             encoding=serialization.Encoding.DER,
-            format=serialization.PrivateFormat.TraditionalOpenSSL,
-            encryption_algorithm=serialization.NoEncryption()
+            format=serialization.PrivateFormat.PKCS8,
+            encryption_algorithm=serialization.BestAvailableEncryption(self._p.encode())
         )
         return
 
diff --git a/source/app/controllers/utils.py b/source/app/controllers/utils.py
index 9630edd..8259af0 100644
--- a/source/app/controllers/utils.py
+++ b/source/app/controllers/utils.py
@@ -767,7 +767,7 @@ def _cancel_with_cert(invoice, args, auth, certificado):
     pac = PACS[auth['pac']]()
     # ~ info = {'cer': cert.cer_pem, 'key': cert.key_pem, 'pass': '', 'args': args}
     info = {'cer': cert.cer_pem, 'key': cert.key_pem,
-        'key_enc': cert._key_der, 'pass': cert._p.hex(), 'args': args}
+        'key_enc': cert._key_der, 'pass': cert._p, 'args': args}
 
     result = pac.cancel(invoice.xml, info, auth)
     if pac.error: