diff --git a/pyencrypt/decrypt.py b/pyencrypt/decrypt.py
index 140fd77..66cb602 100644
--- a/pyencrypt/decrypt.py
+++ b/pyencrypt/decrypt.py
@@ -1,9 +1,12 @@
-from pathlib import Path
 import os
+from functools import lru_cache
+from pathlib import Path
+
 from pyencrypt.aes import aes_decrypt
 from pyencrypt.ntt import intt
 
 
+@lru_cache(maxsize=128)
 def decrypt_key(cipher_key: str, d: int, n: int) -> str:
     plain_ls = list()
     for num in map(int, cipher_key.split("O")):
diff --git a/pyencrypt/loader.py b/pyencrypt/loader.py
index cefe5b1..56f78a7 100644
--- a/pyencrypt/loader.py
+++ b/pyencrypt/loader.py
@@ -2,7 +2,7 @@
 import sys
 import traceback
 import types
-from importlib import abc
+from importlib import abc, machinery
 from importlib._bootstrap_external import _NamespacePath
 from importlib.machinery import ModuleSpec
 from importlib.util import spec_from_loader
@@ -21,6 +21,9 @@ def __dir__(self) -> Iterable[str]:
         return []
 
 
+ENCRYPT_SUFFIX = ".pye"
+
+
 class EncryptFileLoader(abc.SourceLoader, Base):
     POSSIBLE_PATH = [
         Path(os.path.expanduser("~")) / ".licenses" / "license.lic",
@@ -79,12 +82,17 @@ def find_spec(
     ) -> ModuleSpec:
         if path:
             if isinstance(path, _NamespacePath):
-                file_path = Path(path._path[0]) / f'{fullname.rsplit(".", 1)[-1]}.pye'
+                file_path = (
+                    Path(path._path[0])
+                    / f'{fullname.rsplit(".", 1)[-1]}{ENCRYPT_SUFFIX}'
+                )
             else:
-                file_path = Path(path[0]) / f'{fullname.rsplit(".", 1)[-1]}.pye'
+                file_path = (
+                    Path(path[0]) / f'{fullname.rsplit(".", 1)[-1]}{ENCRYPT_SUFFIX}'
+                )
         else:
             for p in sys.path:
-                file_path = Path(p) / f"{fullname}.pye"
+                file_path = Path(p) / f"{fullname}{ENCRYPT_SUFFIX}"
                 if file_path.exists():
                     break
         file_path = file_path.absolute().as_posix()
@@ -99,4 +107,5 @@ def invalidate_caches(cls):
 
 
 # TODO: generate randomly AES Class
+machinery.EXTENSION_SUFFIXES.append(ENCRYPT_SUFFIX)
 sys.meta_path.insert(0, EncryptFileFinder)