diff --git a/pyartifactory/models/artifact.py b/pyartifactory/models/artifact.py
index 1615b94..effe21b 100644
--- a/pyartifactory/models/artifact.py
+++ b/pyartifactory/models/artifact.py
@@ -39,9 +39,9 @@ def generate(cls, file_: Path) -> Checksums:
 class OriginalChecksums(BaseModel):
     """Models original checksums."""
 
-    sha256: str
-    sha1: str
-    md5: str
+    sha256: Optional[str] = None
+    sha1: Optional[str] = None
+    md5: Optional[str] = None
 
 
 class Child(BaseModel):