1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
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,
// Buffer <-> base64 string methods
encodeBufferToBase64,
decodeBase64ToBuffer,
generateSalt,
}
// Takes a Pojo, returns cypher 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 = encodeBufferToBase64(vector)
var vaultStr = encodeBufferToBase64(buffer)
return `${vaultStr}\\${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('\\')
const encryptedData = decodeBase64ToBuffer(parts[0])
const vector = decodeBase64ToBuffer(parts[1])
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
})
.catch(function (reason) {
throw new Error('Incorrect password')
})
}
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) {
var stripStr = (str.slice(0, 2) === '0x') ? str.slice(2) : str
var buf = new Uint8Array(stripStr.length / 2)
for (var i = 0; i < stripStr.length; i += 2) {
var seg = stripStr.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
}
function encodeBufferToBase64 (buf) {
var b64encoded = btoa(String.fromCharCode.apply(null, buf))
return b64encoded
}
function decodeBase64ToBuffer (base64) {
var buf = new Uint8Array(atob(base64).split('')
.map(function (c) {
return c.charCodeAt(0)
}))
return buf
}
function generateSalt (byteCount = 32) {
var view = new Uint8Array(byteCount)
global.crypto.getRandomValues(view)
var b64encoded = btoa(String.fromCharCode.apply(null, view))
return b64encoded
}
|
