ssb-encryption-format

A tool that you install as a devDependency to check whether your encryption format for SSB messages is correct and ready to be installed in ssb-db2.

This tool helps you create new encryption formats that are compatible with ssb-db2 (and maybe one day other databases).

Installation

npm install --save-dev ssb-encryption-format

Usage

const {check} = require('ssb-encryption-format');

const myEncryptionFormat = {
  // ...
};

// Pass your encryption format:
check(myEncryptionFormat, (err) => {
  // `err` if the format is incorrect, else it is undefined
});

In case your encryption format implement setup(), then you can also pass an onSetup function as an argument to check(). This is useful in case you need to do some extra preparation after setup() but before encrypt()/decrypt() is run:

function onSetup() {
  myEncryptionFormat.prepareSomething();
}

check(myEncryptionFormat, onSetup, (err) => {
  // ...
});

Spec

An encryption format specifies how to encrypt and decrypt JavaScript buffers (these could be SSB messages from any feed format) using a particular encryption scheme and algorithms. Every encryption format is a plugin-like object with:

name
setup(config, cb)
teardown(config, cb)
encrypt(plaintext, opts)
decrypt(ciphertext, opts)

Fields and functions

Your encryption format must include these properties:

`name`

A string to name this format. Try to use computer-friendly names, not human-friendly names. Avoid spaces and select short unique names.

The name will also be appended to the ciphertexts when they are base64-stringified. Do NOT include a dot in the name, use only lowercase alphanumeric characters.

`setup(config, cb)`

An OPTIONAL function that you can use to asynchronously setup your encryption format. This function is called when the encryption format is installed in ssb-db2.

The config argument is the same config object that usually comes from secret-stack, and the cb is a function you call with zero arguments once your setup has completed.

`teardown(cb)`

An OPTIONAL function that you can use to asynchronously teardown your encryption format. This function is called when the encryption format is no longer needed in ssb-db2 or when the ssb instance is closed.

`encrypt(plaintext, opts)`

Takes a plaintext as a Buffer and opts object and MUST return a Buffer representing the ciphertext.

You can assume opts has the following properties:

opts.keys: the "ssb-keys"-style cryptographic keypair object of the current SSB peer
opts.recps: an array of identifiers (usually strings such as sigil IDs or SSB URIs) of the recipients of the ciphertext
opts.previous: a string representing the message ID of the previous SSB message before this plaintext

`decrypt(ciphertext, opts)`

Takes a ciphertext as a Buffer and an opts object and MUST return a Buffer representing the plaintext.