US Patent 9639687 Multiply-encrypting data requiring multiple keys for decryption

A server receives a piece of data for encryption. The server encrypts the piece of data such that no single key can decrypt the encrypted piece of data and any combination of a first multiple of unique keys taken a second multiple at a time are capable of decrypting the encrypted piece of data. Each of the first multiple of unique keys is tied to account credentials of a different user. The second multiple is less than or equal to the first multiple. The encrypted piece of data is returned.