A method for storing data on a storage entity (SE) includes: computing a file identifier for a file to be stored on the SE; checking if the file has already been stored using the file identifier; generating a user-specific private and public identifier, wherein generating the user-specific private identifier is based on using an oblivious key generation protocol between the client and a trusted entity, and wherein the user-specific private identifier is a deterministic private identifier; updating or computing tags of the file by the client such that the updating or computing is homomorphic in the user-specific private identifier and in parts of the file; and providing the user-specific public identifier, the updated tags and a proof of possession of the secret identifier to the SE to enable the SE to store information associated with the file.