diff options
Diffstat (limited to 'packages/meshbay-hub/src/meshbay_hub/static/keyderive.js')
| -rw-r--r-- | packages/meshbay-hub/src/meshbay_hub/static/keyderive.js | 218 |
1 files changed, 130 insertions, 88 deletions
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js b/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js index ff3da33..a27522d 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js @@ -67,11 +67,35 @@ async function generateKeypairs() { // ── Password → AES key ──────────────────────────────────────────────────────── -/** - * Derive an AES-256 key from password + username using PBKDF2-SHA512. - * Used for encrypting the keypair bundle. - */ -async function deriveEncryptionKey(password, username) { +// Argon2id parameters for the keypair bundle. +// +// This is the one KDF in the browser that guards something an adversary can take +// away and attack at leisure: the bundle is stored on every node whose group its +// owner joins (finding C4). PBKDF2 was the wrong tool — it is compute-only, which +// is exactly what a GPU is good at, so 600k iterations bought far less than the +// wall-clock time suggested. +// +// 128 MB / t=3 / p=1 measured at ~640 ms through this WASM build on a desktop. +// Memory is the lever, not time: each guess must hold 128 MB, so a 24 GB card +// fits ~187 in parallel and its bandwidth caps it near 2k guesses/s, against no +// ceiling at all for PBKDF2. 256 MB would double that again at ~1.3 s, which is +// too much to ask of a phone for something paid at every sign-in. +const ARGON2_MEM_KIB = 131072; // 128 MB +const ARGON2_TIME = 3; +const ARGON2_LANES = 1; + +// Bundles written before this carry no marker and are read with the old KDF. +// They are re-encrypted the first time their owner signs in (see upgradeBundle). +const BUNDLE_V2_MAGIC = 'MBK2'; + +function _argon2() { + const a = (typeof window !== 'undefined' && window.argon2) || globalThis.argon2; + if (!a) throw new Error('Argon2 unavailable — vendor/argon2.min.js did not load'); + return a; +} + +/** Legacy: PBKDF2-SHA512. Kept to read bundles written before the change. */ +async function deriveEncryptionKeyV1(password, username) { const enc = new TextEncoder(); const km = await crypto.subtle.importKey( 'raw', enc.encode(password), 'PBKDF2', false, ['deriveKey']); @@ -86,6 +110,27 @@ async function deriveEncryptionKey(password, username) { ); } +/** + * Derive the bundle key with Argon2id. + * + * The salt stays deterministic and domain-separated per user, as before: it is + * what lets the key be derived once at sign-in and kept, instead of holding the + * passphrase in memory to re-derive it whenever a bundle turns up. It is unique + * per account, so it does what a salt is for — no shared precomputation. + */ +async function deriveEncryptionKey(password, username) { + const enc = new TextEncoder(); + const salt = new Uint8Array(await crypto.subtle.digest( + 'SHA-256', enc.encode(`meshbay:bundle:v2:${username}`))).slice(0, 16); + const out = await _argon2().hash({ + pass: password, salt, + time: ARGON2_TIME, mem: ARGON2_MEM_KIB, parallelism: ARGON2_LANES, + hashLen: 32, type: _argon2().ArgonType.Argon2id, + }); + return crypto.subtle.importKey( + 'raw', out.hash, { name: 'AES-GCM' }, false, ['encrypt', 'decrypt']); +} + // ── Bundle encryption ───────────────────────────────────────────────────────── /** @@ -94,29 +139,42 @@ async function deriveEncryptionKey(password, username) { */ async function encryptBundle(skEdRaw, skXRaw, password, username) { const aesKey = await deriveEncryptionKey(password, username); + return encryptBundleWithKey(skEdRaw, skXRaw, aesKey); +} + +/** Same, when the key was already derived at sign-in. Always writes v2. */ +async function encryptBundleWithKey(skEdRaw, skXRaw, aesKey) { const nonce = crypto.getRandomValues(new Uint8Array(12)); const data = new TextEncoder().encode(JSON.stringify({ skEd: btoa(String.fromCharCode(...new Uint8Array(skEdRaw))), skX: btoa(String.fromCharCode(...new Uint8Array(skXRaw))), })); const ct = await crypto.subtle.encrypt({ name: 'AES-GCM', iv: nonce }, aesKey, data); - // Return base64(nonce || ciphertext) - const out = new Uint8Array(nonce.length + ct.byteLength); - out.set(nonce); - out.set(new Uint8Array(ct), nonce.length); + // base64( "MBK2" || nonce || ciphertext ). The marker is what tells a reader + // which KDF produced the key, so old bundles stay readable and new ones are + // never fed to the old derivation. + const magic = new TextEncoder().encode(BUNDLE_V2_MAGIC); + const out = new Uint8Array(magic.length + nonce.length + ct.byteLength); + out.set(magic); + out.set(nonce, magic.length); + out.set(new Uint8Array(ct), magic.length + nonce.length); return btoa(String.fromCharCode(...out)); } +function bundleVersion(bundleB64) { + try { + return atob(bundleB64).startsWith(BUNDLE_V2_MAGIC) ? 2 : 1; + } catch { return 1; } +} + /** * Decrypt a keypair bundle. Throws if password is wrong. */ async function decryptBundle(bundleB64, password, username) { - const aesKey = await deriveEncryptionKey(password, username); - const raw = Uint8Array.from(atob(bundleB64), c => c.charCodeAt(0)); - const nonce = raw.slice(0, 12); - const ct = raw.slice(12); - const plain = await crypto.subtle.decrypt({ name: 'AES-GCM', iv: nonce }, aesKey, ct); - return JSON.parse(new TextDecoder().decode(plain)); + const key = bundleVersion(bundleB64) === 2 + ? await deriveEncryptionKey(password, username) + : await deriveEncryptionKeyV1(password, username); + return decryptBundleWithKey(bundleB64, key); } // ── Registration ────────────────────────────────────────────────────────────── @@ -131,45 +189,62 @@ async function decryptBundle(bundleB64, password, username) { * Returns the raw private keys for immediate use after registration. */ async function registerUser(username, email, password) { - const { skEdRaw, pkEdRaw, skXRaw, pkXRaw } = await generateKeypairs(); - - const pkEdCrypto = await crypto.subtle.importKey('spki', pkEdRaw, 'Ed25519', true, ['verify']); - const pkXCrypto = await crypto.subtle.importKey('spki', pkXRaw, 'X25519', true, []); - const pkEdBytes = new Uint8Array(await crypto.subtle.exportKey('raw', pkEdCrypto)); - const pkXBytes = new Uint8Array(await crypto.subtle.exportKey('raw', pkXCrypto)); - - const encBundle = await encryptBundle(skEdRaw, skXRaw, password, username); + // No keypair here any more. Identity keys are per node: one is generated the + // first time this account joins a given node, encrypted under the passphrase, + // and left with that node. So an operator who cracks what sits on their own + // disk holds a key that is worthless anywhere else — and on their own node, + // one that unlocks nothing they did not already have. + // + // It also means the hub stores no user key to publish, which is what H3 read. const authKey = await deriveAuthKey(password, username); const resp = await fetch(`${HUB}/v1/users/register`, { method: 'POST', headers: { 'Content-Type': 'application/json' }, - body: JSON.stringify({ - username, - email, - auth_key: authKey, - pk_user_ed25519: btoa(String.fromCharCode(...pkEdBytes)), - pk_user_x25519: btoa(String.fromCharCode(...pkXBytes)), - }), + body: JSON.stringify({ username, email, auth_key: authKey }), }); if (!resp.ok) throw new Error(`Registration failed: ${await resp.text()}`); + return { registered: true }; +} - // Store encrypted bundle locally — will be backed up to node on first group connect - try { localStorage.setItem(`meshbay_kp_${username}`, encBundle); } catch {} - - return { skEdRaw, skXRaw, pkEdBytes, pkXBytes, keypairBundleEnc: encBundle }; +/** + * A fresh identity for one node, encrypted under the passphrase-derived key. + * + * Returns { skEdB64, skXB64, pkXB64, bundleEnc } — the bundle goes to that node + * and nowhere else, and is what any other browser fetches to become the same + * person there. + */ +async function generateNodeIdentity(bundleKey) { + const { skEdRaw, pkEdRaw, skXRaw, pkXRaw } = await generateKeypairs(); + const b64 = (buf) => btoa(String.fromCharCode(...new Uint8Array(buf))); + const pkXCrypto = await crypto.subtle.importKey('spki', pkXRaw, { name: 'X25519' }, true, []); + const pkXBytes = new Uint8Array(await crypto.subtle.exportKey('raw', pkXCrypto)); + return { + skEdB64: b64(skEdRaw), + skXB64: b64(skXRaw), + pkXB64: b64(pkXBytes), + bundleEnc: await encryptBundleWithKey(skEdRaw, skXRaw, bundleKey.v2 || bundleKey), + }; } /** * Decrypt a keypair bundle using a pre-derived AES-256 CryptoKey. * Used when the bundle is fetched from the node (bundleKey was derived at login). */ -async function decryptBundleWithKey(bundleB64, aesKey) { +async function decryptBundleWithKey(bundleB64, aesKeyOrPair) { + const v2 = bundleVersion(bundleB64) === 2; + // Callers derive both keys at sign-in and pass the pair, because which one a + // bundle needs is only known once it has been read — and the passphrase is + // deliberately not kept around to derive the other one later. + const key = (aesKeyOrPair && aesKeyOrPair.v2) + ? (v2 ? aesKeyOrPair.v2 : aesKeyOrPair.v1) + : aesKeyOrPair; const raw = Uint8Array.from(atob(bundleB64), c => c.charCodeAt(0)); - const nonce = raw.slice(0, 12); - const ct = raw.slice(12); - const plain = await crypto.subtle.decrypt({ name: 'AES-GCM', iv: nonce }, aesKey, ct); + const off = v2 ? BUNDLE_V2_MAGIC.length : 0; + const nonce = raw.slice(off, off + 12); + const ct = raw.slice(off + 12); + const plain = await crypto.subtle.decrypt({ name: 'AES-GCM', iv: nonce }, key, ct); return JSON.parse(new TextDecoder().decode(plain)); } @@ -195,67 +270,34 @@ async function loginAndRecover(username, password) { const result = { accessToken: data.access_token, refreshToken: data.refresh_token, - bundleKey: await deriveEncryptionKey(password, username), + // Both, so a bundle written before the KDF changed can still be opened — + // and re-written with the new one on the next backup. + bundleKey: { + v2: await deriveEncryptionKey(password, username), + v1: await deriveEncryptionKeyV1(password, username), + }, }; - // localStorage bundle = new registration, not yet pushed to node - const bundleEnc = (typeof localStorage !== 'undefined' - && localStorage.getItem(`meshbay_kp_${username}`)) || null; - - if (bundleEnc) { - const keys = await decryptBundle(bundleEnc, password, username); - result.skEdB64 = keys.skEd; - result.skXB64 = keys.skX; - result.keypairBundleEnc = bundleEnc; - } - + // Nothing else to recover at sign-in. Identity keys belong to a node, so they + // are fetched from the node being connected to (or generated there on a first + // join) — see transport.js. All that is needed here is the key that opens them. return result; } -async function regenerateKeys(token, username, password) { - const { skEdRaw, pkEdRaw, skXRaw, pkXRaw } = await generateKeypairs(); - - const pkEdCrypto = await crypto.subtle.importKey('spki', pkEdRaw, 'Ed25519', true, ['verify']); - const pkXCrypto = await crypto.subtle.importKey('spki', pkXRaw, 'X25519', true, []); - const pkEdBytes = new Uint8Array(await crypto.subtle.exportKey('raw', pkEdCrypto)); - const pkXBytes = new Uint8Array(await crypto.subtle.exportKey('raw', pkXCrypto)); - - const resp = await fetch(`${HUB}/v1/users/me/keys`, { - method: 'PUT', - headers: { - 'Content-Type': 'application/json', - 'Authorization': `Bearer ${token}`, - }, - body: JSON.stringify({ - pk_user_ed25519: btoa(String.fromCharCode(...pkEdBytes)), - pk_user_x25519: btoa(String.fromCharCode(...pkXBytes)), - }), - }); - - if (!resp.ok) throw new Error(`Key rotation failed: ${await resp.text()}`); - - const encBundle = await encryptBundle(skEdRaw, skXRaw, password, username); - try { localStorage.setItem(`meshbay_kp_${username}`, encBundle); } catch {} - - return { - skEdB64: btoa(String.fromCharCode(...new Uint8Array(skEdRaw))), - skXB64: btoa(String.fromCharCode(...new Uint8Array(skXRaw))), - pkEdB64: btoa(String.fromCharCode(...pkEdBytes)), - pkXB64: btoa(String.fromCharCode(...pkXBytes)), - keypairBundleEnc: encBundle, - }; -} +// regenerateKeys() removed. Rotating an identity is now per node: the operator +// runs `meshbay-node member unpin <user>` and issues a fresh code. A hub call +// that silently changed what every node believed about someone was the wrong +// shape for this. -async function signChallenge(skEdPkcs8B64, challengeB64) { +async function signBytes(skEdPkcs8B64, message) { const skRaw = Uint8Array.from(atob(skEdPkcs8B64), c => c.charCodeAt(0)); const sk = await crypto.subtle.importKey( 'pkcs8', skRaw, { name: 'Ed25519' }, false, ['sign']); - const challenge = Uint8Array.from(atob(challengeB64), c => c.charCodeAt(0)); - const sig = await crypto.subtle.sign('Ed25519', sk, challenge); + const sig = await crypto.subtle.sign('Ed25519', sk, message); return btoa(String.fromCharCode(...new Uint8Array(sig))); } window.MeshBayKeys = { - registerUser, loginAndRecover, regenerateKeys, generateKeypairs, signChallenge, - deriveAuthKey, decryptBundleWithKey, + registerUser, loginAndRecover, generateNodeIdentity, generateKeypairs, signBytes, + deriveAuthKey, decryptBundleWithKey, encryptBundleWithKey, bundleVersion, }; |