big refactor

app/keychain.js

@@ -0,0 +1,212 @@
+import Nanobus from 'nanobus';
+import { arrayToB64, b64ToArray } from './utils';
+
+const encoder = new TextEncoder();
+const decoder = new TextDecoder();
+
+export default class Keychain extends Nanobus {
+  constructor(secretKeyB64, nonce, ivB64) {
+    super('Keychain');
+    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 !== this.nonce) {
+      this.emit('nonceChanged', n);
+    }
+    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));
+  }
+}