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-rw-r--r--app/scripts/lib/encryptor.js119
1 files changed, 119 insertions, 0 deletions
diff --git a/app/scripts/lib/encryptor.js b/app/scripts/lib/encryptor.js
new file mode 100644
index 000000000..91d6ed5ce
--- /dev/null
+++ b/app/scripts/lib/encryptor.js
@@ -0,0 +1,119 @@
+var ethUtil = require('ethereumjs-util')
+
+module.exports = {
+
+ // Simple encryption methods:
+ encrypt,
+ decrypt,
+
+ // More advanced encryption methods:
+ keyFromPassword,
+ encryptWithKey,
+ decryptWithKey,
+
+ // Buffer <-> String methods
+ convertArrayBufferViewtoString,
+ convertStringToArrayBufferView,
+
+ // Buffer <-> Hex string methods
+ serializeBufferForStorage,
+ serializeBufferFromStorage,
+}
+
+// Takes a Pojo, returns encrypted text.
+function encrypt (password, dataObj) {
+ return keyFromPassword(password)
+ .then(function (passwordDerivedKey) {
+ return encryptWithKey(passwordDerivedKey, dataObj)
+ })
+}
+
+function encryptWithKey (key, dataObj) {
+ var data = JSON.stringify(dataObj)
+ var dataBuffer = convertStringToArrayBufferView(data)
+ var vector = global.crypto.getRandomValues(new Uint8Array(16))
+
+ return global.crypto.subtle.encrypt({
+ name: 'AES-GCM',
+ iv: vector,
+ }, key, dataBuffer).then(function(buf){
+ var buffer = new Uint8Array(buf)
+ var vectorStr = serializeBufferForStorage(vector)
+ return serializeBufferForStorage(buffer) + vectorStr
+ })
+}
+
+// Takes encrypted text, returns the restored Pojo.
+function decrypt (password, text) {
+ return keyFromPassword(password)
+ .then(function (key) {
+ return decryptWithKey(key, text)
+ })
+}
+
+function decryptWithKey (key, text) {
+ const parts = text.split('0x')
+ const encryptedData = serializeBufferFromStorage(parts[1])
+ const vector = serializeBufferFromStorage(parts[2])
+ return crypto.subtle.decrypt({name: 'AES-GCM', iv: vector}, key, encryptedData)
+ .then(function(result){
+ const decryptedData = new Uint8Array(result)
+ const decryptedStr = convertArrayBufferViewtoString(decryptedData)
+ const decryptedObj = JSON.parse(decryptedStr)
+ return decryptedObj
+ })
+}
+
+function convertStringToArrayBufferView (str) {
+ var bytes = new Uint8Array(str.length)
+ for (var i = 0; i < str.length; i++) {
+ bytes[i] = str.charCodeAt(i)
+ }
+
+ return bytes
+}
+
+function convertArrayBufferViewtoString (buffer) {
+ var str = ''
+ for (var i = 0; i < buffer.byteLength; i++) {
+ str += String.fromCharCode(buffer[i])
+ }
+
+ return str
+}
+
+function keyFromPassword (password) {
+ var passBuffer = convertStringToArrayBufferView(password)
+ return global.crypto.subtle.digest('SHA-256', passBuffer)
+ .then(function (passHash){
+ return global.crypto.subtle.importKey('raw', passHash, {name: 'AES-GCM'}, false, ['encrypt', 'decrypt'])
+ })
+}
+
+function serializeBufferFromStorage (str) {
+ str = ethUtil.stripHexPrefix(str)
+ var buf = new Uint8Array(str.length / 2)
+ for (var i = 0; i < str.length; i += 2) {
+ var seg = str.substr(i, 2)
+ buf[i / 2] = parseInt(seg, 16)
+ }
+ return buf
+}
+
+// Should return a string, ready for storage, in hex format.
+function serializeBufferForStorage (buffer) {
+ var result = '0x'
+ var len = buffer.length || buffer.byteLength
+ for (var i = 0; i < len; i++) {
+ result += unprefixedHex(buffer[i])
+ }
+ return result
+}
+
+function unprefixedHex (num) {
+ var hex = num.toString(16)
+ while (hex.length < 2) {
+ hex = '0' + hex
+ }
+ return hex
+}