Patent ID: 8150038

Claim:
A method of storing electronic information, the method comprising: a) encrypting target electronically stored information (“ESI”) with a first encryption key to form a first encrypted ESI; b) partitioning the first encrypted ESI into a first set of encrypted ESI partitions, the encrypted ESI partitions being such that a predetermined number of the encrypted ESI partitions are able to reconstruct the first encrypted ESI; c) encrypting the first set of encrypted ESI partitions with a first set of user encryption keys to form a first set of user-associated encrypted ESI partitions, each encrypted ESI partition of the first set of user-associated encrypted ESI partitions having an associated user encryption key; d) making available the first set of user-associated encrypted ESI partitions to a first set of users, wherein each user knows a decryption key for an encrypted ESI partition of the first set of user-associated encrypted ESI partitions; e) accessing the target electronically stored information; f) encrypting the target ESI with a second encryption key to form a second encrypted ESI; g) partitioning the second encrypted ESI into a second set of encrypted ESI partitions, the second set of encrypted ESI partitions being such that a predetermined number of encrypted ESI partitions from the second set are able to reconstruct the second encrypted ESI; h) encrypting the second set of encrypted ESI partitions with a second set of user encryption keys to form a second set of user-associated encrypted ESI partitions, each encrypted ESI partition of the second set of user-associated encrypted ESI partitions having an associated user encryption key, wherein the second set of user encryption keys is the same or different than the first set of encryption keys and wherein the first set of user encryption keys and the second set of user encryption keys each independently include a private portion of a public key pair; i) making the second set of user-associated encrypted ESI partitions available to a second set of users, wherein each user of the second set of users knows a decryption key for an encrypted ESI partition of the second set of user-associated encrypted ESI partitions; and j) deleting the private portion of the first set of public key pairs after a predetermined time.