diff --git a/source/app/controllers/pacs/cfdi_cert.py b/source/app/controllers/pacs/cfdi_cert.py
index 2bacac4..210ec53 100644
--- a/source/app/controllers/pacs/cfdi_cert.py
+++ b/source/app/controllers/pacs/cfdi_cert.py
@@ -28,7 +28,17 @@ class SATCertificate(object):
         self._init_values()
         self._get_data_cer(cer)
         self._get_data_key(key, password)
+        self._test()
+
+    def _test(self):
         self._p = self._get_hash()
+        key = self._get_key('')
+        self._key_der = key.private_bytes(
+            encoding=serialization.Encoding.DER,
+            format=serialization.PrivateFormat.TraditionalOpenSSL,
+            encryption_algorithm=serialization.NoEncryption()
+        )
+        return
 
     def _init_values(self):
         self._rfc = ''
@@ -45,6 +55,7 @@ class SATCertificate(object):
         self._cer_pem = ''
         self._cer_txt = ''
         self._key_enc = b''
+        self._key_der = b''
         self._p12 = b''
         self._cer_modulus = 0
         self._key_modulus = 0
diff --git a/source/app/controllers/utils.py b/source/app/controllers/utils.py
index 7ccd468..9630edd 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_enc, 'pass': cert._p.hex(), 'args': args}
+        'key_enc': cert._key_der, 'pass': cert._p.hex(), 'args': args}
 
     result = pac.cancel(invoice.xml, info, auth)
     if pac.error: