diff --git a/google/auth/crypt/es256.py b/google/auth/crypt/es256.py
index c6d6176..7465cd6 100644
--- a/google/auth/crypt/es256.py
+++ b/google/auth/crypt/es256.py
@@ -53,8 +53,8 @@
         sig_bytes = _helpers.to_bytes(signature)
         if len(sig_bytes) != 64:
             return False
-        r = utils.int_from_bytes(sig_bytes[:32], byteorder="big")
-        s = utils.int_from_bytes(sig_bytes[32:], byteorder="big")
+        r = int.from_bytes(sig_bytes[:32], byteorder="big")
+        s = int.from_bytes(sig_bytes[32:], byteorder="big")
         asn1_sig = encode_dss_signature(r, s)
 
         message = _helpers.to_bytes(message)
diff --git a/system_tests/secrets.tar.enc b/system_tests/secrets.tar.enc
index 62ef5a7..dab541c 100644
--- a/system_tests/secrets.tar.enc
+++ b/system_tests/secrets.tar.enc
Binary files differ