diff --git a/app/api.py b/app/api.py
index c6d5d48c..4d292231 100644
--- a/app/api.py
+++ b/app/api.py
@@ -1,3 +1,4 @@
+import functools
 import time
 import uuid
 from pathlib import Path
@@ -79,6 +80,11 @@ def get_db():
 # Authentication helpers
 # ------------------------------------------------------------------------------
 oauth2_scheme = OAuth2PasswordBearerOrAuthCookie(tokenUrl="auth")
+# Version of oauth2_scheme that does not raise an error if the token is
+# invalid or missing
+oauth2_scheme_no_error = OAuth2PasswordBearerOrAuthCookie(
+    tokenUrl="auth", auto_error=False
+)
 
 
 def create_token(user_id: str):
@@ -87,11 +93,20 @@ def create_token(user_id: str):
 
 def get_current_user(
     token: Annotated[str, Depends(oauth2_scheme)], db: Session = Depends(get_db)
-):
+) -> schemas.UserBase:
+    """Get the current user if authenticated.
+
+    This function is used as a dependency in endpoints that require
+    authentication. It raises an HTTPException if the user is not
+    authenticated.
+
+    :param token: the authentication token
+    :param db: the database session
+    :raises HTTPException: if the user is not authenticated
+    :return: the current user
+    """
     if token and "__U" in token:
-        current_user: schemas.UserBase = crud.update_user_last_used_field(
-            db, token=token
-        )
+        current_user = crud.update_user_last_used_field(db, token=token)
         if current_user:
             return current_user
     raise HTTPException(
@@ -101,6 +116,24 @@ def get_current_user(
     )
 
 
+def get_current_user_optional(
+    token: Annotated[str, Depends(oauth2_scheme_no_error)],
+    db: Session = Depends(get_db),
+) -> schemas.UserBase | None:
+    """Get the current user if authenticated, None otherwise.
+
+    This function is used as a dependency in endpoints that require
+    authentication, but where the user is optional.
+
+    :param token: the authentication token
+    :param db: the database session
+    :return: the current user if authenticated, None otherwise
+    """
+    if token and "__U" in token:
+        return crud.update_user_last_used_field(db, token=token)
+    return None
+
+
 # Routes
 # ------------------------------------------------------------------------------
 
@@ -166,14 +199,26 @@ def authentication(
     )
 
 
-def price_transformer(prices: list[Price]) -> list[Price]:
+def price_transformer(
+    prices: list[Price], current_user: schemas.UserBase | None = None
+) -> list[Price]:
     """Transformer function used to remove the file_path of private proofs.
 
+    If current_user is None, the file_path is removed for all proofs that are
+    not public. Otherwise, the file_path is removed for all proofs that are not
+    public and do not belong to the current user.
+
     :param prices: the list of prices to transform
+    :param current_user: the current user, if authenticated
     :return: the transformed list of prices
     """
+    user_id = current_user.user_id if current_user else None
     for price in prices:
-        if price.proof and price.proof.is_public is False:
+        if (
+            price.proof
+            and price.proof.is_public is False
+            and price.proof.owner != user_id
+        ):
             price.proof.file_path = None
     return prices
 
@@ -182,9 +227,12 @@ def price_transformer(prices: list[Price]) -> list[Price]:
 def get_price(
     filters: schemas.PriceFilter = FilterDepends(schemas.PriceFilter),
     db: Session = Depends(get_db),
+    current_user: schemas.UserBase | None = Depends(get_current_user_optional),
 ):
     return paginate(
-        db, crud.get_prices_query(filters=filters), transformer=price_transformer
+        db,
+        crud.get_prices_query(filters=filters),
+        transformer=functools.partial(price_transformer, current_user=current_user),
     )
 
 
diff --git a/app/crud.py b/app/crud.py
index 493d2c4e..cdf1a203 100644
--- a/app/crud.py
+++ b/app/crud.py
@@ -48,7 +48,7 @@ def create_user(db: Session, user: UserBase):
     return db_user
 
 
-def update_user_last_used_field(db: Session, token: str):
+def update_user_last_used_field(db: Session, token: str) -> UserBase | None:
     db_user = get_user_by_token(db, token=token)
     if db_user:
         db.query(User).filter(User.user_id == db_user.user_id).update(
@@ -57,7 +57,7 @@ def update_user_last_used_field(db: Session, token: str):
         db.commit()
         db.refresh(db_user)
         return db_user
-    return False
+    return None
 
 
 def delete_user(db: Session, user_id: UserBase):