This is the "Caps" key for accessing the SSB protocol. It will be updated whenever breaking changes are made. See the secret-handshake paper for a full explanation:

https://dominictarr.github.io/secret-handshake-paper/shs.pdf

npm install --save ssb-caps

From JavaScript:

var caps = require('ssb-caps')
console.log(caps) // JSON object: {shs, sign}
console.log(caps.shs) // this is a string to be interpreted as base64
console.log(caps.sign) // this is so far null
var buf = Buffer.from(caps.shs, 'base64')

From other languages: download the caps.json file from this package and parse it using some JSON parser in your language.

There is nothing special about the Caps SHS value, it was randomly generated in the Node.js REPL with:

crypto.randomBytes(32).toString('base64')

This value is presented as a string to be interpreted in base64. To convert from this string to binary (in Node.js):

Buffer.from(require('ssb-caps').shs, 'base64')

If this library updates the Caps, we MUST issue a new major version.

this is used to hmac messages before signing/verification. because originally, ssb does not use anything, this defaults to null.

peer invites sign a message content using the private key which is given to the guest. It is the hash of the string "peer-invites"

crypto.createHash('sha256').update('peer-invites', 'utf8').digest('base64')

• Written in 2015 by 'Dominic Tarr' dominic.tarr@gmail.com
• Contributor: Andre Medeiros andre@staltz.com

To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide. This software is distributed without any warranty.

You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see https://creativecommons.org/publicdomain/zero/1.0/.