diff --git a/app/core/__init__.py b/app/core/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/app/core/passwords.py b/app/core/passwords.py
new file mode 100644
index 0000000..01c9e4d
--- /dev/null
+++ b/app/core/passwords.py
@@ -0,0 +1,50 @@
+from argon2 import PasswordHasher
+from argon2.exceptions import InvalidHashError, VerifyMismatchError
+from argon2.low_level import Type
+from zxcvbn import zxcvbn
+
+from app.config import settings
+
+
+class WeakPasswordError(ValueError):
+    pass
+
+
+_hasher = PasswordHasher(
+    time_cost=3,
+    memory_cost=65536,
+    parallelism=4,
+    hash_len=32,
+    salt_len=16,
+    type=Type.ID,
+)
+
+
+def _peppered(password: str) -> str:
+    return password + settings.password_pepper
+
+
+#  возвращает хэш Argon2id от password + pepper;
+def hash_password(password: str) -> str:
+    return _hasher.hash(_peppered(password))
+
+
+# проверяет соответствие
+def verify_password(password: str, hashed: str) -> bool:
+    try:
+        return _hasher.verify(hashed, _peppered(password))
+    except (VerifyMismatchError, InvalidHashError):
+        return False
+
+
+# проверяет политику
+def validate_policy(password: str, user_inputs: list[str] | None = None) -> None:
+    # длина не меньше settings.password_min_length;
+    if len(password) < settings.password_min_length:
+        raise WeakPasswordError(
+            f"Password must be >= {settings.password_min_length} chars"
+        )
+    result = zxcvbn(password, user_inputs=user_inputs or [])
+    # оценка стойкости через zxcvbn должна быть не ниже 3 (по шкале 0–4);
+    if result["score"] < 3:
+        raise WeakPasswordError("Password is too weak")