Encrypted query-based access to data

A method for providing access to an electronic file, comprising using at least one hardware processor for:

• receiving an electronic file in association with a plain text tag;
• creating multiple (n) encrypted portions of the electronic file;
• storing each encrypted portion separately;
• deriving multiple (n) differently encrypted ciphertexts by applying cipher information to encrypt the plaintext tag multiple times according to a map of the encrypted file portions, wherein the map is based on the cipher information;
• associating each encrypted portion with the different one of the ciphertexts;
• and
• separately indexing each stored encrypted portion with the associated ciphertext,
• wherein the cipher information comprises a seed and n,
• wherein applying the cipher information comprises generating multiple encryption keys from a key generating function using the seed and n,
• wherein the map assigns a unique combination of the multiple encryption keys to each encrypted portion,
• wherein encrypting the plaintext tag multiple times according to the map comprises, for each encrypted file portion, using a symmetric encryption algorithm and the assigned unique combination of the encryption keys,
• wherein storing each encrypted portion separately comprises storing each encrypted portion in association with a different storage location string, and
• wherein separately indexing each stored encrypted portion comprises storing the associated ciphertext with an encrypted storage location string derived by encrypting the storage location string of the stored encrypted portion using the symmetric encryption algorithm with the unique combination of the encryption keys assigned by the map.

A method for retrieving an electronic file, comprising using at least one hardware processor for:

• receiving cipher information;
• receiving a search query that matches a plaintext tag associated with an electronic file, wherein the electronic file is stored as multiple (n) encrypted portions, each indexed by a differently encrypted ciphertext derived from the plaintext tag;
• deriving multiple encrypted search queries matching at least some of the n ciphertexts by applying the cipher information to encrypt the search query multiple times according to a map of the encrypted file portions, wherein the map is based on the cipher information and associates each encrypted portion with the different one of the ciphertexts;
• querying using the multiple encrypted search queries;
• retrieving at least some of the n encrypted portions;
• and
• recovering the electronic file from the retrieved encrypted portions,
• wherein the cipher information comprises a seed and n,
• wherein applying the cipher information comprises generating multiple encryption keys from a key generating function using the seed and n,
• wherein the map assigns multiple unique combinations of the multiple encryption keys to the n encrypted file portions,
• wherein encrypting the search query multiple times according to the map comprises encrypting the search query using the symmetric encryption algorithm and one of the unique combinations of the encryption keys assigned by the map, and
• wherein retrieving the at least some of the n multiple encrypted portions of the electronic file comprises, for each encrypted search query, retrieving an encrypted locator string stored with the ciphertext matching the encrypted search query, decrypting the encrypted locator string using the unique combination of the encryption keys used to derive the encrypted search query, and retrieving the encrypted file portion using the decrypted locator string.