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encrypt and decrypt messages in browser

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Sam Hadow
2025-03-09 19:05:24 +01:00
parent 744e1fae29
commit b7907c94ae
6 changed files with 60 additions and 11 deletions
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57
src/public/chat.js
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@@ -31,12 +31,16 @@ function init_ratchets(order, user_pubkey) {
}
socket.on('chat message', (msg, room) => {
socket.on('chat message', (msg, room, tag_received, iv, nonce) => {
console.log(`received: ${msg}`);
console.log(sharedsecret);
const item = document.createElement('li');
item.textContent = msg;
const messages = document.getElementById(`messages-${room}`);
const associated_data = fromHexString(Array.from((document.getElementById('pubkey')).classList).find(className => className.startsWith('key-')).replace('key-', ''));
const pubkey = Array.from(messages.classList).find(className => className.startsWith('key-')).replace('key-', '');
const item = document.createElement('li');
let {plaintext, tag} = decrypt_message(msg, pubkey, fromHexString(iv), fromHexString(nonce), associated_data);
item.textContent = plaintext
console.log(tag);
console.log(tag_received);
messages.appendChild(item);
window.scrollTo(0, document.body.scrollHeight);
});
@@ -69,12 +73,55 @@ export function create_listener(form, input) {
form.addEventListener('submit', function(e) {
e.preventDefault();
if (input.value) {
socket.emit('chat message', input.value, form.id);
const pubkey = Array.from(form.classList).find(className => className.startsWith('key-')).replace('key-', '');
let {cipher, tag, iv, nonce} = encrypt_message(input.value, pubkey)
socket.emit('chat message', cipher, form.id, tag, iv, nonce);
input.value = '';
}
});
}
function encrypt_message(message, user_pubkey) {
let encryption_key = sending_ratchets[user_pubkey].next();
let encoded_msg = (new TextEncoder()).encode(message);
let iv = generateRandomUint8Array();
let nonce = generateRandomUint8Array();
let associated_data = fromHexString(user_pubkey);
let {cipher, tag} = keccakAEAD.encrypt(encryption_key, encoded_msg, iv, associated_data, nonce);
console.log(iv)
console.log(nonce)
console.log(associated_data)
console.log(encryption_key)
console.log(encoded_msg)
console.log(cipher)
return {cipher: toHexString(cipher),
tag: toHexString(tag),
iv: toHexString(iv),
nonce: toHexString(nonce)
};
}
function decrypt_message(cipher, user_pubkey, iv, nonce, associated_data) {
let decryption_key = receiving_ratchets[user_pubkey].next();
let cipher_array = fromHexString(cipher);
let {plaintext, tag} = keccakAEAD.decrypt(decryption_key, cipher_array, iv, associated_data, nonce);
console.log(iv)
console.log(nonce)
console.log(associated_data)
console.log(decryption_key)
console.log(plaintext)
console.log(cipher_array)
return {plaintext: (new TextDecoder('utf-8')).decode(plaintext),
tag: toHexString(tag)
};
}
function generateRandomUint8Array(length = 16) {
const randomArray = new Uint8Array(length);
window.crypto.getRandomValues(randomArray);
return randomArray;
}
const fromHexString = (hexString) =>
Uint8Array.from(hexString.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)));