A method executing an instruction (300) to execute a query (q) for a data block (102) and determining whether the data block is stored in a block stash (370). When the data block is stored in the block stash during a download phase, the method includes removing the data block from the block stash, sending a fake query (304) to a distributed system (140) to retrieve a random data block stored in memory (114) of a distributed system (140), and discarding the random data block. When a current version of the data block is stored in the block stash during an overwrite phase, the method includes sending a fake query to the distributed system to retrieve another random data block stored in the memory of the distributed system, decrypting and re-encrypting the random data block with fresh randomness, and re-uploading the re-encrypted random data block onto the distributed system.