Patent ID: 7539867

Claim:
A method comprising: accessing a file composed of a data stream and a metadata stream at a computing device of a serverless distributed file system, the data stream containing multiple encrypted blocks that are each encrypted using hashes of a plaintext version of the encrypted blocks, the metadata stream containing an indexing structure to index to the individual encrypted blocks, the indexing structure having a leaf node for each corresponding encrypted block that contains a verification value used to verify the corresponding encrypted block; traversing the indexing structure to a leaf node associated with a target encrypted block at the computing device; verifying, at the computing device, an authenticity of the target encrypted block independently of other encrypted blocks by using the verification value in the leaf node associated with the target encrypted block; generating a delegation certificate at the computing device, wherein the computing device is associated with a writer of the file, and the delegation certificate allows one or more additional computing devices to verify as a group authenticity of the file when the computing device is unavailable to verify the authenticity of the file; and signing the delegation certificate at the computing device with a private key of the writer of the file.