A method for re-keying an encrypted data file, the data file being stored chunkwise on a storage entity (SE), data file chunks being encrypted with a global secret, and the method being performed by one or more computing devices, includes updating the global secret for encryption data for a data chunk to be re-keyed such that an output of a non-interactive oblivious key exchange is used to identify the private key of the data chunk to be re-keyed with a new private key, wherein the non-interactive oblivious key exchange uses an oblivious protocol; and reencrypting the data chunk to be re-keyed with the updated global secret.