Maimo

Just Another Storage

• Remote storage: Open storage channels to a remote storage provider over Tor
• Lightweight: Platform-optimized using Blake3-based hash, verified streaming, and encryption algorithms
• Local files can be deleted: Periodic verification of remotely stored data
• Remote files can be retrieved: Files can be proven to exist remotely and sent back
• Low write-amplification: Bytes stored are only slightly larger than bytes read

Caution! This is experimental, potentially dangerous technology that hasn't yet been audited!

Notable Dependencies

• Embedded
  • Blake3 cryptographic hash algorithm
  • Bao Verified Streaming for Provable Data Possession
  • XChaCha8Blake3Siv encryption
  • Torut Tor controller
  • zstd_safe dictionary compression
  • Rusqlite embedded SQL database
  • Sled embedded keystore
• External
  • Local Tor SOCKS proxy

Roadmap

0.0.1 - Experiment

• Bao encoding
• Bao verification
• Bao extraction

0.0.2 - File storage

• Sled for path lookup
• file SQL
  • Schema
  • Insert
  • Query
• Encode files in the Maimo Data folder, and store them in a configured storage volume
• Decode files stored in a configured storage volume, and restore them to the Maimo Data folder
• Verify a random slice of a file (accounting for files of varying sizes)
• Display encoded file list
• Paths are indexed in sqlite (path, file name, file size, creation & modification dates, file hash)
• Multiple files can be stored

0.0.3 - Crate & Testing

• Exports all CLI commands as functions
• Serial integration tests added for crate
• Needs more documentation and tests

0.0.4 - Tor networking

• Generate Onion v3 address
• peer SQL
  • Schema
  • Insert
  • Query
• Open & Receive TCP socket over Tor hidden service

0.0.5 - Authenticated encryption

• Authentication between storage client and storage provider using Onion v3 addresses
• Blake3 keyed hashes as a MAC
• Files are encrypted using XChaCha8Blake3Siv authenticated encryption
  • Caution! Experimental encryption!
• CSPRNGs where RNGs are used
• Use randomized padding instead of zeroed padding
• Zeroization of private keys after dropped from memory

0.1.0 - Proof of Concept

Goal: A storage client that can compress, encrypt, and store data on a remote storage provider using Tor. The storage client can check periodically that the data is still present and consistent on the remote storage provider against only a local 32-byte Blake3 hash without a full local reference copy, allowing the client to delete its local data, trusting that it can retrieve it later in-full. The storage client can then retrieve the data from the storage provider and decode it on-disk.

• Storage client can open a storage channel to storage provider over Tor
  • Storage provider generates Onion v3 address to provide to storage client out-of-band
  • Storage client generates Onion v3 address of their own
  • TCP socket is established from storage client to storage provider over Tor hidden service
• Storage client can store data on storage provider
  • Storage client can supply their node with specified path to data to store remotely
  • Data is encoded using Bao, hashed with Blake3, and transmitted over TCP socket over Tor circuit
  • Blake3 hash is persisted locally
  • Optional: Delete the local data
• Storage client can periodically verify the data they sent is still present and consistent over time
  • Storage client asks for a 4KB slice of data at a random offset of their choosing from the storage storage provider
  • Storage client checks 4KB slice against the same offset against local Bao Blake3 hash
• Storage client can retrieve data from storage provider over storage channel
  • Data is written to disk at specified path
• Files are compressed using zstd dictionary compression
• Individual files can be retrieved from storage provider
• Files can be removed
• Files can be overwritten, with old revisions still retrievable
• The number of older revisions can be configured
• Embeddable library available, with documentation
• Parallel processing for lots of files

0.1.1

• Complex volume and storage layouts

Future

After this basic functionality exists, more exciting features are planned, including apps on the Start9 Embassy and Umbrel!