diff --git a/src/saml2/sigver.py b/src/saml2/sigver.py
index c32136a..82c1a71 100644
--- a/src/saml2/sigver.py
+++ b/src/saml2/sigver.py
@@ -664,7 +664,8 @@ def read_cert_from_file(cert_file, cert_type):
         return ""
 
     if cert_type == "pem":
-        line = read_file(cert_file).split("\n")
+        line = open(cert_file).read().replace("\r\n", "\n").split("\n")
+
         if line[0] == "-----BEGIN CERTIFICATE-----":
             line = line[1:]
         elif line[0] == "-----BEGIN PUBLIC KEY-----":