Primary · 2017
RAIN: A Bio-Inspired Communication and Data Storage Infrastructure
Monti & Rasmussen. Artificial Life 23(4), 552–557. MIT Press. Every parameter on this page — r, K, Z, the 36-node lifetime — is theirs.
For engineers · sourced from the 2017 paper
How RAIN works.
The machinery behind the plain-English story: erasure coding, villages, ledger-backed monitoring, and distributed self-repair — as specified by Monti & Rasmussen in Artificial Life 23(4). Where this page says a number, the paper said it first. Prefer plain words? Start at What is RAIN.
01 · Erasure coding
A file becomes K = r·N blocks. Any N rebuild it.
Files are encrypted on the owner's device, then erasure-coded into K blocks such that any N of them reconstruct the original — Reed–Solomon-style polynomial codes, the same family that protects optical media. The paper's working redundancy ratio is r = 1.5: a file kept as twelve blocks survives the loss of any four. No block alone reveals anything; the encryption happens before coding, so a node stores noise.
- Redundancy ratio (paper)
- r = 1.5
- Worked example
- 12 blocks, any 8 rebuild
- Code family
- Reed–Solomon erasure codes
- Encryption
- Client-side, before anything leaves the device
02 · Villages
Blocks live in a village of K nodes that trade storage.
A village is a group of K nodes — inexpensive, always-on devices like a Raspberry Pi with a flash drive — that store one another's blocks in exchange for having their own stored. The paper models each node contributing a fixed share, Z = 100 GB. Every node operates on local interactions with a limited set of peers it does not need to trust a priori; there is no coordinator, no central index, and no single point whose failure matters.
- Village size
- K nodes
- Storage share (paper model)
- Z = 100 GB per node
- Trust required between peers
- None a priori
- Central point of failure
- None
03 · Monitoring & self-repair
Merkle-tree monitoring on a village ledger. Repair is automatic.
Nodes continuously audit one another's availability and integrity through Merkle-tree hashes recorded on a ledger the village shares. Because the village is small and its nodes are always on, this ledger is local — kept consistent among peers without global consensus, secured with proofs of space over storage the nodes have already committed, not with mined work. When the number of live blocks for a file falls toward the threshold, the surviving nodes regenerate the missing blocks from what remains and place them on fresh nodes. A tampered block fails its hash, is discarded, and is rebuilt the same way.
- Integrity checks
- Merkle-tree hashes, continuous
- Record of checks
- Village-local ledger
- Sybil / commitment defense
- Proofs of space (no mining)
- Repair
- Distributed regeneration onto fresh nodes
04 · What the model yields
36 nodes
give a stored file an expected lifetime on the order of the age of the Earth.
The paper's reliability model, with home-grade hardware and realistic failure rates: redundancy plus continuous repair compounds, so village lifetime grows explosively with size. Thirty-six ordinary nodes is enough to put a file's expected survival in the billions of years. Not because any machine lasts — because the village never stops replacing what fails.
05 · Against the alternatives
Engineered for hardware you cannot trust.
- Against the cloud
- A data center concentrates custody: one operator, one key-holder, one legal and physical target — and more than 3% of the world's power consumption feeds the model. RAIN's operator does not exist: keys never leave the owner, and custody is the village.
- Against storage-trading networks
- Systems in the Storj lineage assume well-connected, reliable machines. RAIN is engineered for the opposite — home links and drives that fail — and pulls its reliability from erasure coding plus self-repair, not from the hardware underneath.
- Against blockchains
- A global chain needs asynchronous worldwide consensus, so it pays in proof-of-work and latency. A village is small, always-on, and local: its ledger stays consistent among peers, secured by proofs of space over storage already committed. No mining, no token, no dedicated hardware.
Sources
Check every claim.
Read the paper
The full reference list — Reed & Solomon 1960, Merkle 1988, proofs of space, the working papers — lives on the reading list.
Plain-English version: What is RAIN.