LarpixClient/main.js

const collapseDmsBtn = document.getElementById("collapse-dms");

const sidebarHome = document.getElementById("sidebar-home");
const sidebarHomeButton = sidebarHome.children.item(1);
const sidebarHomeIndicator = sidebarHome.children.item(0);

const sidebarAdd = document.getElementById("sidebar-add");
const sidebarAddButton = sidebarAdd.children.item(1);
const sidebarAddIndicator = sidebarAdd.children.item(0);



function delay(time) {
    return new Promise(resolve => setTimeout(resolve, time));
}
async function packetEncPass(pass, key, username) {
    let nonce;
    let fetchRes = await fetchAsync(`${url}/nextnonce?u=${username}`);
    try {
        nonce = await decryptString(fetchRes, key);
    }
    catch(err) {
        nonce = await decryptString(fetchRes, "");
    }

    return await encryptString(pass, nonce + key);
}

async function calcCommunicationKeyClient(p, g, pubServer) {
    const secretClientBytes = window.crypto.getRandomValues(new Uint8Array(512));
    const secretClient = BigInt('0x' + Array.from(secretClientBytes).map(b => b.toString(16).padStart(2, '0')).join(''));
    const pubClient = power(BigInt(g), secretClient, BigInt(p));
    const sharedSecret = power(BigInt(pubServer), secretClient, BigInt(p));

    let sharedSecretStr = sharedSecret.toString(16);

    if (sharedSecretStr.length % 2 !== 0) {
        sharedSecretStr = '0' + sharedSecretStr;
    }

    const sharedSecretBytes = new Uint8Array(sharedSecretStr.match(/.{1,2}/g).map(byte => parseInt(byte, 16)));

    const hashBuffer = await window.crypto.subtle.digest('SHA-256', sharedSecretBytes);
    const aesKey = new Uint8Array(hashBuffer);

    return [pubClient.toString(), aesKey];
}

function keyDataFromServerJson(jsonFromServer) {
    const data = JSON.parse(jsonFromServer);

    const p = BigInt(data.p);
    const g = BigInt(data.g);
    const pubServer = BigInt(data.pubServer);

    return [p, g, pubServer, data.idKey]
}

const base64ToUint8 = (base64) => Uint8Array.from(atob(base64), c => c.charCodeAt(0));
const uint8ToBase64 = (uint8) => fixBase64Padding(btoa(String.fromCharCode(...uint8)));

async function encrypt(plainText, keyBytes) {
    const iv = window.crypto.getRandomValues(new Uint8Array(16));
    const encoder = new TextEncoder();
    const data = encoder.encode(plainText);

    const cryptoKey = await window.crypto.subtle.importKey(
        "raw", keyBytes, "AES-CBC", false, ["encrypt"]
    );

    const encryptedContent = await window.crypto.subtle.encrypt(
        {name: "AES-CBC", iv: iv},
        cryptoKey,
        data
    );
    const result = new Uint8Array(iv.length + encryptedContent.byteLength);
    result.set(iv);
    result.set(new Uint8Array(encryptedContent), iv.length);

    return uint8ToBase64(result);
}

async function decrypt(cipherTextBase64, keyBytes) {
    const fullData = base64ToUint8(cipherTextBase64);
    const iv = fullData.slice(0, 16);
    const cipherData = fullData.slice(16);

    const cryptoKey = await window.crypto.subtle.importKey(
        "raw", keyBytes, "AES-CBC", false, ["decrypt"]
    );

    const decrypted = await window.crypto.subtle.decrypt(
        {name: "AES-CBC", iv: iv},
        cryptoKey,
        cipherData
    );

    return new TextDecoder().decode(decrypted);
}


async function getCryptoKey(passphrase) {
    const encoder = new TextEncoder();
    const data = encoder.encode(passphrase);
    const hash = await crypto.subtle.digest('SHA-256', data);
    return await crypto.subtle.importKey('raw', hash, {name: 'AES-CBC'}, false, ['encrypt', 'decrypt']);
}

async function encryptBytes(plainBytes, passphrase) {
    const key = await getCryptoKey(passphrase);
    const iv = crypto.getRandomValues(new Uint8Array(16));

    const encryptedContent = await crypto.subtle.encrypt(
        {name: 'AES-CBC', iv: iv},
        key,
        plainBytes
    );

    const result = new Uint8Array(iv.length + encryptedContent.byteLength);
    result.set(iv);
    result.set(new Uint8Array(encryptedContent), iv.length);
    return result;
}

async function decryptBytes(combinedBytes, passphrase) {
    const key = await getCryptoKey(passphrase);
    const iv = combinedBytes.slice(0, 16);
    const data = combinedBytes.slice(16);

    const decryptedContent = await crypto.subtle.decrypt(
        {name: 'AES-CBC', iv: iv},
        key,
        data
    );

    return new Uint8Array(decryptedContent);
}

async function encryptString(plainText, passphrase) {
    const encoder = new TextEncoder();
    const data = encoder.encode(plainText);
    const pwHash = await crypto.subtle.digest('SHA-256', encoder.encode(passphrase));

    const key = await crypto.subtle.importKey(
        'raw', pwHash, {name: 'AES-CBC'}, false, ['encrypt']
    );

    const iv = crypto.getRandomValues(new Uint8Array(16));
    const encrypted = await crypto.subtle.encrypt(
        {name: 'AES-CBC', iv: iv},
        key,
        data
    );

    const combined = new Uint8Array(iv.length + encrypted.byteLength);
    combined.set(iv);
    combined.set(new Uint8Array(encrypted), iv.length);

    return fixBase64Padding(btoa(String.fromCharCode(...combined)));
}

async function decryptString(base64Text, passphrase) {
    const encoder = new TextEncoder();
    const combined = new Uint8Array(atob(base64Text).split("").map(c => c.charCodeAt(0)));

    const pwHash = await crypto.subtle.digest('SHA-256', encoder.encode(passphrase));
    const key = await crypto.subtle.importKey(
        'raw', pwHash, {name: 'AES-CBC'}, false, ['decrypt']
    );

    const iv = combined.slice(0, 16);
    const data = combined.slice(16);

    const decrypted = await crypto.subtle.decrypt(
        {name: 'AES-CBC', iv: iv},
        key,
        data
    );

    return new TextDecoder().decode(decrypted);
}


async function fetchpost(url, value) {
    let response = await fetch(url, {
        method: "POST",
        credentials: "omit",
        body: value,
        headers: {
            "secret": passwordHash
        }
    });
    let data = await response.text();
    return data;
}

async function fetchAsync(url, sendSecret) {
    let response;
    if (sendSecret) {
        response = await fetch(url, {
            method: "GET", credentials: "omit", headers: {
                "secret": passwordHash
            }
        });
    }
    else
    {
        response = await fetch(url, {method: "GET", credentials: "omit"});
    }
    let data = await response.text();
    return data;
}

async function fetchEncrypted(request, body)
{
    return await decryptString(
        await fetchpost(`${url}/encryptedrequest?u=${username}`, await packetEncPass(

            JSON.stringify({
                string1: request,
                string2: body
            })

            , passwordHash, username))

        , passwordHash);
}

function power(base, exponent, mod) {
    let res = 1n;
    base = base % mod;
    while (exponent > 0n) {
        if (exponent % 2n === 1n) res = (res * base) % mod;
        base = (base * base) % mod;
        exponent = exponent / 2n;
    }
    return res;
}

function fixBase64Padding(base64String) {
    let str = base64String.replace(/-/g, '+').replace(/_/g, '/');
    const pad = str.length % 4;

    if (pad) {
        if (pad === 1) {
            throw new Error("");
        }
        str += '='.repeat(4 - pad);
    }

    return str;
}





collapseDmsBtn.addEventListener("click", () => {
    collapseDmsBtn.classList.toggle("collapsed");
});

sidebarHomeButton.addEventListener("mouseenter", () => {
    sidebarHomeIndicator.classList.add("hover");
});
sidebarHomeButton.addEventListener("mouseleave", () => {
    sidebarHomeIndicator.classList.remove("hover");
});

sidebarAddButton.addEventListener("mouseenter", () => {
    sidebarAddIndicator.classList.add("hover");
});
sidebarAddButton.addEventListener("mouseleave", () => {
    sidebarAddIndicator.classList.remove("hover");
});