Commit 6c591ad213da63c1fc8d5396b439279bc03fe35e
copy from https://scuttlebot.io/more/protocols/secure-scuttlebutt.html
Michael Williams committed on 11/3/2016, 12:21:12 PMParent: f2ddbc9bb74bc33eda174f962215eefeb8dae202
Files changed
| SUMMARY.md | changed |
| assets/gossip-graph1.png | added |
| assets/gossip-graph2.png | added |
| concepts/blob.md | added |
| concepts/feed.md | added |
| concepts/gossip.md | added |
| concepts/identity.md | added |
| concepts/link.md | added |
| concepts/local.md | added |
| concepts/message.md | added |
| concepts/private-message.md | added |
| concepts/pub.md | added |
| SUMMARY.md | ||
|---|---|---|
| @@ -1,8 +1,14 @@ | ||
| 1 | 1 … | |
| 2 | 2 … | *  |
| 3 | 3 … | * [Introduction](README.md) |
| 4 | 4 … | * [Concepts](concepts/index.md) |
| 5 | - - [Append only logs](concepts/append-only-log.md) | |
| 6 | - - [Content addressable storage](concepts/content-addressable-storage.md) | |
| 7 | - - [Key pairs](concepts/key-pairs.md) | |
| 5 … | + - [Identity](concepts/identity.md) | |
| 6 … | + - [Feed](concepts/feed.md) | |
| 7 … | + - [Message](concepts/message.md) | |
| 8 … | + - [Private Message](concepts/private-message.md) | |
| 9 … | + - [Link](concepts/link.md) | |
| 10 … | + - [Gossip](concepts/gossip.md) | |
| 11 … | + - [Local](concepts/local.md) | |
| 12 … | + - [Pub](concepts/pub.md) | |
| 13 … | + - [Blob](concepts/blob.md) | |
| 8 | 14 … | |
| assets/gossip-graph1.png |
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| assets/gossip-graph2.png |
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| concepts/feed.md | ||
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| 1 … | +# Feed | |
| 2 … | + | |
| 3 … | +A feed is a signed append-only sequence of messages. Each identity has exactly one feed. | |
| 4 … | + | |
| 5 … | +Note that append-only means you cannot delete an existing message, or change your history. This is enforced by a per-feed blockchain. This is to ensure the entire network converges on the same state. | |
| concepts/gossip.md | |||
|---|---|---|---|
| @@ -1,0 +1,23 @@ | |||
| 1 … | +# Gossip | ||
| 2 … | + | ||
| 3 … | +## Following | ||
| 4 … | + | ||
| 5 … | +Users choose which feeds to synchronize by following them. Presently, Scuttlebot's replicate plugin, which is enabled by default, looks on the master user's feed for `type: contact` messages to know which users are currently followed. | ||
| 6 … | + | ||
| 7 … | +## Replication | ||
| 8 … | + | ||
| 9 … | +Since feeds are append-only, replication is simple: request all messages in the feed that are newer than the latest message you know about. Scuttlebot maintains a table of known peers, which it cycles through, asking for updates for all followed feeds. | ||
| 10 … | + | ||
| 11 … | +Since feeds are append-only, gossip is simple: request all messages in the feed that are newer than the latest message you know about. Scuttlebot maintains a table of known peers, which it cycles through, asking for updates for all followed feeds. | ||
| 12 … | + | ||
| 13 … | +## Network | ||
| 14 … | + | ||
| 15 … | +The protocol creates a [global gossip network](https://en.wikipedia.org/wiki/Gossip_protocol). This means that information is able to distribute across multiple machines, without requiring direct connections between them. | ||
| 16 … | + | ||
| 17 … | + | ||
| 18 … | + | ||
| 19 … | +Even though Alice and Dan lack a direct connection, they can still exchange feeds: | ||
| 20 … | + | ||
| 21 … | + | ||
| 22 … | + | ||
| 23 … | +This is because gossip creates "transitive" connections between computers. Dan's messages travel through Carla and the Pub to reach Alice, and visa-versa. | ||
| concepts/identity.md | ||
|---|---|---|
| @@ -1,0 +1,5 @@ | ||
| 1 … | +# Identity | |
| 2 … | + | |
| 3 … | +An identity is simply a [ed25519 key pair](http://ed25519.cr.yp.to/). The public key is used as the identifier. | |
| 4 … | + | |
| 5 … | +There is no worldwide store of identities. Users must exchange pubkeys, either by publishing them on their feeds, or out-of-band. | |
| concepts/link.md | ||
|---|---|---|
| @@ -1,0 +1,35 @@ | ||
| 1 … | +# Link | |
| 2 … | + | |
| 3 … | +Messages can reference three types of Secure Scuttlebutt entities: messages, feeds, and blobs (i.e. files). Messages and blobs are referred to by their hashes, but a feed is referred to by its signing public key. | |
| 4 … | + | |
| 5 … | +To indicate the type of ID, a "sigil" is prepended to the string. They are: | |
| 6 … | + | |
| 7 … | +- `@` for feeds | |
| 8 … | +- `%` for messages | |
| 9 … | +- `&` for blobs | |
| 10 … | + | |
| 11 … | +Additionally, each ID has a "tag" appended to indicate the hash or key algorithm. Some example IDs: | |
| 12 … | + | |
| 13 … | +- A feed: `@LA9HYf5rnUJFHHTklKXLLRyrEytayjbFZRo76Aj/qKs=.ed25519` | |
| 14 … | +- A message: `%MPB9vxHO0pvi2ve2wh6Do05ZrV7P6ZjUQ+IEYnzLfTs=.sha256` | |
| 15 … | +- A blob: `&Pe5kTo/V/w4MToasp1IuyMrMcCkQwDOdyzbyD5fy4ac=.sha256` | |
| 16 … | + | |
| 17 … | +When IDs are found in the messages, they may be treated as links, with the keyname acting as a "relation" type. An example of this: | |
| 18 … | + | |
| 19 … | +```shell | |
| 20 … | +sbot publish --type post \ | |
| 21 … | + --root "%MPB9vxHO0pvi2ve2wh6Do05ZrV7P6ZjUQ+IEYnzLfTs=.sha256" \ | |
| 22 … | + --branch "%kRi8MzGDWw2iKNmZak5STshtzJ1D8G/sAj8pa4bVXLI=.sha256" \ | |
| 23 … | + --text "this is a reply!" | |
| 24 … | +``` | |
| 25 … | + | |
| 26 … | +```javascript | |
| 27 … | +sbot.publish({ | |
| 28 … | + type: "post", | |
| 29 … | + root: "%MPB9vxHO0pvi2ve2wh6Do05ZrV7P6ZjUQ+IEYnzLfTs=.sha256", | |
| 30 … | + branch: "%kRi8MzGDWw2iKNmZak5STshtzJ1D8G/sAj8pa4bVXLI=.sha256", | |
| 31 … | + text: "this is a reply!" | |
| 32 … | +}) | |
| 33 … | +``` | |
| 34 … | + | |
| 35 … | +In this example, the root and branch keys are the relations. SSB automatically builds an index based on these links, to allow queries such as "all messages with a root link to this message." | |
| concepts/local.md | ||
|---|---|---|
| @@ -1,0 +1,3 @@ | ||
| 1 … | +# local | |
| 2 … | + | |
| 3 … | +SSB is hostless: each computer installs the same copy of software and has equal rights in the network. Devices discover each other over the LAN with multicast UDP and sync automatically. | |
| concepts/message.md | ||
|---|---|---|
| @@ -1,0 +1,30 @@ | ||
| 1 … | +# Message | |
| 2 … | + | |
| 3 … | +Each message contains: | |
| 4 … | + | |
| 5 … | +A signature | |
| 6 … | +The signing public key | |
| 7 … | +A content-hash of the previous message | |
| 8 … | +A sequence number | |
| 9 … | +A timestamp | |
| 10 … | +An identifier of the hashing algorithm in use (currently only "sha256" is supported) | |
| 11 … | +A content object | |
| 12 … | +Here's an example message: | |
| 13 … | + | |
| 14 … | +``` | |
| 15 … | +{ | |
| 16 … | + "previous": "%26AC+gU0t74jRGVeDY013cVghlZRc0nfUAnMnutGGHM=.sha256", | |
| 17 … | + "author": "@hxGxqPrplLjRG2vtjQL87abX4QKqeLgCwQpS730nNwE=.ed25519", | |
| 18 … | + "sequence": 216, | |
| 19 … | + "timestamp": 1442590513298, | |
| 20 … | + "hash": "sha256", | |
| 21 … | + "content": { | |
| 22 … | + "type": "vote", | |
| 23 … | + "vote": { | |
| 24 … | + "link": "%WbQ4dq0m/zu5jxll9zUbe0iGmDOajCx1ZkLKjZ80JvI=.sha256", | |
| 25 … | + "value": 1 | |
| 26 … | + } | |
| 27 … | + }, | |
| 28 … | + "signature": "Sjq1C3yiKdmi1TWvNqxIk1ZQBf4pPJYl0HHRDVf/xjm5tWJHBaW4kXo6mHPcUMbJYUtc03IvPwVqB+BMnBgmAQ==.sig.ed25519" | |
| 29 … | +} | |
| 30 … | +``` | |
| concepts/private-message.md | ||
|---|---|---|
| @@ -1,0 +1,5 @@ | ||
| 1 … | +# Private Message | |
| 2 … | + | |
| 3 … | +For private sharing, Scuttlebot uses [libsodium](http://doc.libsodium.org/) to encrypt confidential log-entries. Feed IDs are public keys, and so once two feeds are mutually following each other, they can exchange confidential data freely. | |
| 4 … | + | |
| 5 … | +Private-box is a format for encrypting a private message to many parties. It is designed according to the [audit-driven crypto design process](https://github.com/crypto-browserify/crypto-browserify/issues/128). You can find the repository on at [github:dominictarr/private-box](https://github.com/auditdrivencrypto/private-box) | |
| concepts/pub.md | ||
|---|---|---|
| @@ -1,0 +1,3 @@ | ||
| 1 … | +# Pub | |
| 2 … | + | |
| 3 … | +To sync across the Internet, "Pub" nodes run at public IPs and follow users. They are essentially mail-bots which improve uptime and availability. Users generate invite-codes to command Pubs to follow their friends. The Scuttlebot community runs some Pubs, and anybody can create and introduce their own. | |
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