Use Merkle-tree-based storage about qubes-incremental-backup-poc

[v6ak]

First draft:

All items of Merkle tree are encrypted and somehow linked to the particular VM. TODO: describe details.

MAC is not needed for any node except the root one, because other node's ciphertext are authenticated by hash stored in a node that is already authenticated.

Root item

• creation date
• link to previous root item?
• root directory

Directory structure

List of directory item descriptions ordered by name.

Directory item description

• ASCII filename with limited set of characters
• item type (file or directory)
• creation date (?)
• size
• hash(es) of ciphertext (also this is identifier under which it will be references)

File

Just content of the file.