edge-encryptor.js - Documentation

const asmcrypto = require('asmcrypto.js')
+const Unibabel = require('browserify-unibabel')
+
+/**
+ * A Microsoft Edge-specific encryption class that exposes
+ * the interface expected by eth-keykeyring-controller
+ */
+class EdgeEncryptor {
+  /**
+   * Encrypts an arbitrary JavaScript object to cypher text
+   *
+   * @param {string} password Password used to unlock a cryptographic key
+   * @param {Object} dataObject Data to encrypt
+   * @returns {Object} Object containing cypher text, generation vectors, and salt
+   */
+  encrypt (password, dataObject) {
+      var salt = this._generateSalt()
+      return this._keyFromPassword(password, salt)
+          .then(function (key) {
+              var data = JSON.stringify(dataObject)
+              var dataBuffer = Unibabel.utf8ToBuffer(data)
+              var vector = global.crypto.getRandomValues(new Uint8Array(16))
+              var resultbuffer = asmcrypto.AES_GCM.encrypt(dataBuffer, key, vector)
+
+              var buffer = new Uint8Array(resultbuffer)
+              var vectorStr = Unibabel.bufferToBase64(vector)
+              var vaultStr = Unibabel.bufferToBase64(buffer)
+              return JSON.stringify({
+                  data: vaultStr,
+                  iv: vectorStr,
+                  salt: salt,
+              })
+          })
+  }
+
+  /**
+   * Decrypts an arbitrary JavaScript object from cypher text
+   *
+   * @param {string} password Password used to unlock a cryptographic key
+   * @param {string} text Cypher text of an encrypted JavaScript object
+   * @returns {Promise<Object>} Promise resolving to copy of decrypted JavaScript object
+   */
+  decrypt (password, text) {
+      const payload = JSON.parse(text)
+      const salt = payload.salt
+      return this._keyFromPassword(password, salt)
+          .then(function (key) {
+              const encryptedData = Unibabel.base64ToBuffer(payload.data)
+              const vector = Unibabel.base64ToBuffer(payload.iv)
+              return new Promise((resolve, reject) => {
+                  var result
+                  try {
+                      result = asmcrypto.AES_GCM.decrypt(encryptedData, key, vector)
+                  } catch (err) {
+                      return reject(new Error('Incorrect password'))
+                  }
+                  const decryptedData = new Uint8Array(result)
+                  const decryptedStr = Unibabel.bufferToUtf8(decryptedData)
+                  const decryptedObj = JSON.parse(decryptedStr)
+                  resolve(decryptedObj)
+              })
+          })
+  }
+
+  /**
+   * Retrieves a cryptographic key using a password
+   *
+   * @private
+   * @param {string} password Password used to unlock a cryptographic key
+   * @param {string} salt Random base-64 data
+   * @returns {Promise<Object>} Promise resolving to a derived key
+   */
+  _keyFromPassword (password, salt) {
+
+      var passBuffer = Unibabel.utf8ToBuffer(password)
+      var saltBuffer = Unibabel.base64ToBuffer(salt)
+      return new Promise((resolve) => {
+          var key = asmcrypto.PBKDF2_HMAC_SHA256.bytes(passBuffer, saltBuffer, 10000)
+          resolve(key)
+      })
+  }
+
+  /**
+   * Generates random base-64 encoded data
+   *
+   * @private
+   * @returns {string} Randomized base-64 encoded data
+   */
+  _generateSalt (byteCount = 32) {
+      var view = new Uint8Array(byteCount)
+      global.crypto.getRandomValues(view)
+      var b64encoded = btoa(String.fromCharCode.apply(null, view))
+      return b64encoded
+  }
+}
+
+module.exports = EdgeEncryptor
+