envelope-js

A javascript tool for cryptographically "boxing" and "unboxing" messages
following the envelope spec.

envelope supports encryption to individuals and groups

Example Usage

``js
var { box, unbox, CloakedMsgId } = require('envelope-js')
`

...

API

$3

where:
- plain_text Buffer is the content to be "enveloped"
- feed_id Buffer is a type-format-key (TFK) encoded value for the feed authoring a message
- prev_msg_id Buffer is a TFK encoded value of the id of last message of this feeds chain
- msg_key Buffer a randomised 32 Bytes which will be the unique key for this message
- recps_keys Array is a collection of items of form { key, scheme }, where
- key Buffer is the key the particular recipient
- scheme String|Buffer is the type of key / the key management scheme for this recipient

$3

where:
- ciphertext Buffer is envelope
- feed_id Buffer is a type-format-key (TFK) encoded value for the feed authoring a message
- prev_msg_id Buffer is a TFK encoded value of the id of last message of this feeds chain
- trial_keys Array is a collection of items of form { key, scheme }, where
- key Buffer is the key the particular recipient
- scheme String|Buffer is the type of key / the key management scheme for this recipient
- max_attempts Integer (default: 8) how many key_slots you want to assume the envelope has
- plain_text Buffer the envelope contents

NOTE: we also expose unboxKey and unboxBody for convenience.

$3

Used for taking a msg_key (the one-time key for a particular envelope) and deriving other keys used in the envelope (e.g. read_key)

where:
- feed_id Buffer is a TFK encoded id for the feed the envelope is part of
- prev_msg_id Buffer is a TFK encoded id for the message prior to one where our envelope is
- NOTE if this is the first message, then the K part of prev_msg_id's TFK is a zero-filled Buffer.
- derive(key, labels) => new_key function where:
- key Buffer is a seed key which we're going to derive from
- labels Array is a an array of Strings which help define a derivation

$3

Determine a cloaked message id for a published message following the envelope-spec/cloaked_msg_id/README.md

where:
- public_msg_id Buffer is the id of a enveloped message that's been published (it has an id as it's part of a feed / chain)
- read_key Buffer is the read capability (NOT the msg_key) for this message envelope
- cloakedMsgId is an instance with methods:
- toBuffer() => Buffer which returns the cloaked id key as a Buffer
- toString(encoding) => String which returns the cloaked id key as a Buffer (encoding defaults to 'base64')
- mock() => cloakedMsgId a method for testing. populates the id with random content. if using this, instantiate with no args.

$3

where info` is an Array of Buffers.

This is "short length-prefixed encoding", see https://github.com/ssbc/envelope-spec/blob/master/encoding/slp.md

...

License

MIT