import { arrayToB64, b64ToArray } from './utils'; const encoder = new TextEncoder(); const decoder = new TextDecoder(); export default class Keychain { constructor(secretKeyB64, nonce, ivB64) { this._nonce = nonce || 'yRCdyQ1EMSA3mo4rqSkuNQ=='; if (ivB64) { this.iv = b64ToArray(ivB64); } else { this.iv = window.crypto.getRandomValues(new Uint8Array(12)); } if (secretKeyB64) { this.rawSecret = b64ToArray(secretKeyB64); } else { this.rawSecret = window.crypto.getRandomValues(new Uint8Array(16)); } this.secretKeyPromise = window.crypto.subtle.importKey( 'raw', this.rawSecret, 'HKDF', false, ['deriveKey'] ); this.encryptKeyPromise = this.secretKeyPromise.then(function(secretKey) { return window.crypto.subtle.deriveKey( { name: 'HKDF', salt: new Uint8Array(), info: encoder.encode('encryption'), hash: 'SHA-256' }, secretKey, { name: 'AES-GCM', length: 128 }, false, ['encrypt', 'decrypt'] ); }); this.metaKeyPromise = this.secretKeyPromise.then(function(secretKey) { return window.crypto.subtle.deriveKey( { name: 'HKDF', salt: new Uint8Array(), info: encoder.encode('metadata'), hash: 'SHA-256' }, secretKey, { name: 'AES-GCM', length: 128 }, false, ['encrypt', 'decrypt'] ); }); this.authKeyPromise = this.secretKeyPromise.then(function(secretKey) { return window.crypto.subtle.deriveKey( { name: 'HKDF', salt: new Uint8Array(), info: encoder.encode('authentication'), hash: 'SHA-256' }, secretKey, { name: 'HMAC', hash: { name: 'SHA-256' } }, true, ['sign'] ); }); } get nonce() { return this._nonce; } set nonce(n) { if (n && n !== this._nonce) { this._nonce = n; } } setIV(ivB64) { this.iv = b64ToArray(ivB64); } setPassword(password, shareUrl) { this.authKeyPromise = window.crypto.subtle .importKey('raw', encoder.encode(password), { name: 'PBKDF2' }, false, [ 'deriveKey' ]) .then(passwordKey => window.crypto.subtle.deriveKey( { name: 'PBKDF2', salt: encoder.encode(shareUrl), iterations: 100, hash: 'SHA-256' }, passwordKey, { name: 'HMAC', hash: 'SHA-256' }, true, ['sign'] ) ); } setAuthKey(authKeyB64) { this.authKeyPromise = window.crypto.subtle.importKey( 'raw', b64ToArray(authKeyB64), { name: 'HMAC', hash: 'SHA-256' }, true, ['sign'] ); } async authKeyB64() { const authKey = await this.authKeyPromise; const rawAuth = await window.crypto.subtle.exportKey('raw', authKey); return arrayToB64(new Uint8Array(rawAuth)); } async authHeader() { const authKey = await this.authKeyPromise; const sig = await window.crypto.subtle.sign( { name: 'HMAC' }, authKey, b64ToArray(this.nonce) ); return `send-v1 ${arrayToB64(new Uint8Array(sig))}`; } async encryptFile(plaintext) { const encryptKey = await this.encryptKeyPromise; const ciphertext = await window.crypto.subtle.encrypt( { name: 'AES-GCM', iv: this.iv, tagLength: 128 }, encryptKey, plaintext ); return ciphertext; } async encryptMetadata(metadata) { const metaKey = await this.metaKeyPromise; const ciphertext = await window.crypto.subtle.encrypt( { name: 'AES-GCM', iv: new Uint8Array(12), tagLength: 128 }, metaKey, encoder.encode( JSON.stringify({ iv: arrayToB64(this.iv), name: metadata.name, type: metadata.type || 'application/octet-stream' }) ) ); return ciphertext; } async decryptFile(ciphertext) { const encryptKey = await this.encryptKeyPromise; const plaintext = await window.crypto.subtle.decrypt( { name: 'AES-GCM', iv: this.iv, tagLength: 128 }, encryptKey, ciphertext ); return plaintext; } async decryptMetadata(ciphertext) { const metaKey = await this.metaKeyPromise; const plaintext = await window.crypto.subtle.decrypt( { name: 'AES-GCM', iv: new Uint8Array(12), tagLength: 128 }, metaKey, ciphertext ); return JSON.parse(decoder.decode(plaintext)); } }