diff --git a/google/auth/transport/_custom_tls_signer.py b/google/auth/transport/_custom_tls_signer.py
index 22a510daa..dfef6d00f 100644
--- a/google/auth/transport/_custom_tls_signer.py
+++ b/google/auth/transport/_custom_tls_signer.py
@@ -192,8 +192,8 @@ def __init__(self, enterprise_cert_file_path):
 
                     {
                         "libs": {
-                            "signer_library": "...",
-                            "offload_library": "..."
+                            "ecp_client": "...",
+                            "tls_offload": "..."
                         }
                     }
         """
@@ -206,8 +206,8 @@ def load_libraries(self):
             with open(self._enterprise_cert_file_path, "r") as f:
                 enterprise_cert_json = json.load(f)
                 libs = enterprise_cert_json["libs"]
-                signer_library = libs["signer_library"]
-                offload_library = libs["offload_library"]
+                signer_library = libs["ecp_client"]
+                offload_library = libs["tls_offload"]
         except (KeyError, ValueError) as caught_exc:
             new_exc = exceptions.MutualTLSChannelError(
                 "enterprise cert file is invalid", caught_exc
diff --git a/system_tests/secrets.tar.enc b/system_tests/secrets.tar.enc
index 735379ef1..df5017ab6 100644
Binary files a/system_tests/secrets.tar.enc and b/system_tests/secrets.tar.enc differ
diff --git a/tests/data/enterprise_cert_valid.json b/tests/data/enterprise_cert_valid.json
index de4b2d009..e445f55f8 100644
--- a/tests/data/enterprise_cert_valid.json
+++ b/tests/data/enterprise_cert_valid.json
@@ -1,6 +1,6 @@
 {
     "libs": {
-        "signer_library": "/path/to/signer/lib",
-        "offload_library": "/path/to/offload/lib"
+        "ecp_client": "/path/to/signer/lib",
+        "tls_offload": "/path/to/offload/lib"
     }
-}
\ No newline at end of file
+}