pzp-db/lib/encryption.js

102 lines
2.3 KiB
JavaScript

const base58 = require('bs58')
const b4a = require('b4a')
const MsgV3 = require('./msg-v3')
/**
* @typedef {import('./index').RecPresent} RecPresent
* @typedef {import('ppppp-keypair').Keypair} Keypair
*
* @typedef {Buffer | Uint8Array} B4A
*
* @typedef {{
* name: string;
* setup?: (config: any, cb: any) => void;
* onReady?: (cb: any) => void;
* encrypt: (plaintext: B4A, opts: any) => B4A;
* decrypt: (ciphertext: B4A, opts: any) => B4A | null;
* }} EncryptionFormat
*/
/**
* @param {string} str
*/
function ciphertextStrToBuffer(str) {
const dot = str.indexOf('.')
return b4a.from(str.slice(0, dot), 'base64')
}
/**
* TODO: eventually get rid of this
* @param {Keypair} keypair
*/
function keypairToSSBKeys(keypair) {
const _public = b4a.from(base58.decode(keypair.public)).toString('base64')
const _private = b4a.from(base58.decode(keypair.private)).toString('base64')
return {
id: `@${_public}.ed25519`,
curve: keypair.curve,
public: _public,
private: _private,
}
}
/**
* @param {RecPresent} rec
* @param {any} peer
* @param {any} config
* @returns {RecPresent}
*/
function decrypt(rec, peer, config) {
const msgEncrypted = rec.msg
const { data } = msgEncrypted
if (typeof data !== 'string') return rec
const encryptionFormat = peer.db.findEncryptionFormatFor(data)
if (!encryptionFormat) return rec
// Decrypt
const ciphertextBuf = ciphertextStrToBuffer(data)
const opts = { keys: keypairToSSBKeys(config.keypair) }
const plaintextBuf = encryptionFormat.decrypt(ciphertextBuf, opts)
if (!plaintextBuf) return rec
// Reconstruct KVT in JS encoding
const msgDecrypted = MsgV3.fromPlaintextBuffer(plaintextBuf, msgEncrypted)
return {
hash: rec.hash,
msg: msgDecrypted,
received: rec.received,
misc: {
...rec.misc,
private: true,
originalData: data,
encryptionFormat: encryptionFormat.name,
},
}
}
/**
* @param {RecPresent} rec
*/
function reEncrypt(rec) {
return {
hash: rec.hash,
msg: { ...rec.msg, data: rec.misc.originalData },
received: rec.received,
...(rec.misc.size
? {
misc: {
offset: rec.misc.offset,
size: rec.misc.size,
},
}
: null),
}
}
module.exports = {
decrypt,
reEncrypt,
}