diff --git a/models/translation/utils.py b/models/translation/utils.py
index 5b15f16a..c41fbb88 100644
--- a/models/translation/utils.py
+++ b/models/translation/utils.py
@@ -5,30 +5,57 @@ from os import makedirs as os_makedirs
 from requests import get as requests_get, head as requests_head
 from tqdm import tqdm
 from typing import Callable
+import hashlib
 
 ctranslate2_weights = {
     "small": { # M2M-100 418M-parameter model
         "url": "https://bit.ly/33fM1AO",
         "directory_name": "m2m100_418m",
-        "tokenizer": "facebook/m2m100_418M"
+        "tokenizer": "facebook/m2m100_418M",
+        "hash": {
+            "model.bin": "e7c26a9abb5260abd0268fbe3040714070dec254a990b4d7fd3f74c5230e3acb",
+            "sentencepiece.model": "d8f7c76ed2a5e0822be39f0a4f95a55eb19c78f4593ce609e2edbc2aea4d380a",
+            "shared_vocabulary.txt": "bd440aa21b8ca3453fc792a0018a1f3fe68b3464aadddd4d16a4b72f73c86d8c",
+        }
     },
     "large": { # M2M-100 1.2B-parameter model
         "url": "https://bit.ly/3GYiaed",
         "directory_name": "m2m100_12b",
-        "tokenizer": "facebook/m2m100_12b"
+        "tokenizer": "facebook/m2m100_1.2b",
+        "hash": {
+            "model.bin": "abb7bf4ba7e5e016b6e3ed480c752459b2f783ac8fca372e7587675e5bf3a919",
+            "sentencepiece.model": "d8f7c76ed2a5e0822be39f0a4f95a55eb19c78f4593ce609e2edbc2aea4d380a",
+            "shared_vocabulary.txt": "bd440aa21b8ca3453fc792a0018a1f3fe68b3464aadddd4d16a4b72f73c86d8c",
+        }
     },
 }
 
+def calculate_file_hash(file_path, block_size=65536):
+    hash_object = hashlib.sha256()
+
+    with open(file_path, 'rb') as file:
+        for block in iter(lambda: file.read(block_size), b''):
+            hash_object.update(block)
+
+    return hash_object.hexdigest()
+
 def downloadCTranslate2Weight(path, weight_type="small", ctranslate2_weights=ctranslate2_weights, func=None):
     url = ctranslate2_weights[weight_type]["url"]
     filename = 'weight.zip'
     directory_name = 'weight'
     current_directory = path
     weight_directory_name = ctranslate2_weights[weight_type]["directory_name"]
+    hash_data = ctranslate2_weights[weight_type]["hash"]
     files = ["model.bin", "sentencepiece.model", "shared_vocabulary.txt"]
 
     # check already downloaded
     if all(os_path.exists(os_path.join(current_directory, directory_name, weight_directory_name, file)) for file in files):
+        # check hash
+        for file in files:
+            original_hash = hash_data[file]
+            current_hash = calculate_file_hash(os_path.join(current_directory, directory_name, weight_directory_name, file))
+            if original_hash != current_hash:
+                break
         return
 
     try:
@@ -40,7 +67,7 @@ def downloadCTranslate2Weight(path, weight_type="small", ctranslate2_weights=ctr
             pbar = tqdm(total=file_size, unit="B", unit_scale=True)
             total_chunk = 0
             with open(os_path.join(tmp_path, filename), 'wb') as file:
-                for chunk in res.iter_content(chunk_size=1024):
+                for chunk in res.iter_content(chunk_size=1024*5):
                     file.write(chunk)
                     pbar.update(len(chunk))
                     if isinstance(func, Callable):