Patent ID: 8041677

Claim:
A backup and restore system comprising: a server-side portion that receives backup and restore requests and processes the backup and restore requests by returning encrypted data blocks in response to a restore request, and storing encrypted data blocks and file signatures in response to a backup request; and wherein a file signature includes a header that specifies a file-signature version and an ordered sequence of block descriptors, each block descriptor including a block hash and a block length; and wherein a file signature is generated from a file by partitioning the file into an ordered sequence of natural blocks; and coalescing the natural blocks, in order, in a an ordered sequence of approximately fixed-size blocks; and for each approximately fixed-size block, generating a block descriptor that includes an indication of the length of the block and a cryptographic hash of the block; and appending the header to the generated block descriptors; a client-side portion that provides a user-interface that allows files to designated for continuous backup, includes a service process that detects changes to files designated for continuous backup, computes file signatures, computes, by file-signature comparison, blocks needed to be stored for backup and restore operations, and issues requests for backup and restore operations, and includes a transport service process for exchanging requests and data with the server-side portion.