git ssb

1
'use strict'
2
var sodium     = require('chloride')
3
4
var pb         = require('private-box')
5
6
var u          = require('./util')
7
8
var isBuffer = Buffer.isBuffer
9
10
//UTILS
11
12
function clone (obj) {
13
  var _obj = {}
14
  for(var k in obj) {
15
    if(Object.hasOwnProperty.call(obj, k))
16
      _obj[k] = obj[k]
17
  }
18
  return _obj
19
}
20
21
var hmac = sodium.crypto_auth
22
23
exports.hash = u.hash
24
25
exports.getTag = u.getTag
26
27
function isObject (o) {
28
  return 'object' === typeof o
29
}
30
31
function isFunction (f) {
32
  return 'function' === typeof f
33
}
34
35
function isString(s) {
36
  return 'string' === typeof s
37
}
38
39
var curves = {}
40
curves.ed25519 = require('./sodium')
41
42
function getCurve(keys) {
43
  var curve = keys.curve
44
45
  if(!keys.curve && isString(keys.public))
46
    keys = keys.public
47
48
  if(!curve && isString(keys))
49
    curve = u.getTag(keys)
50
51
  if(!curves[curve]) {
52
    throw new Error(
53
      'unkown curve:' + curve +
54
      ' expected: '+Object.keys(curves)
55
    )
56
  }
57
58
  return curve
59
}
60
61
//this should return a key pair:
62
// {curve: curve, public: Buffer, private: Buffer}
63
64
exports.generate = function (curve, seed) {
65
  curve = curve || 'ed25519'
66
67
  if(!curves[curve])
68
    throw new Error('unknown curve:'+curve)
69
70
  return u.keysToJSON(curves[curve].generate(seed), curve)
71
}
72
73
//import functions for loading/saving keys from storage
74
var storage = require('./storage')(exports.generate)
75
for(var key in storage) exports[key] = storage[key]
76
77
78
exports.loadOrCreate = function (filename, cb) {
79
  exports.load(filename, function (err, keys) {
80
    if(!err) return cb(null, keys)
81
    exports.create(filename, cb)
82
  })
83
}
84
85
exports.loadOrCreateSync = function (filename) {
86
  try {
87
    return exports.loadSync(filename)
88
  } catch (err) {
89
    return exports.createSync(filename)
90
  }
91
}
92
93
94
//takes a public key and a hash and returns a signature.
95
//(a signature must be a node buffer)
96
97
function sign (keys, msg) {
98
  if(isString(msg))
99
    msg = new Buffer(msg)
100
  if(!isBuffer(msg))
101
    throw new Error('msg should be buffer')
102
  var curve = getCurve(keys)
103
104
  return curves[curve]
105
    .sign(u.toBuffer(keys.private || keys), msg)
106
    .toString('base64')+'.sig.'+curve
107
108
}
109
110
//takes a public key, signature, and a hash
111
//and returns true if the signature was valid.
112
function verify (keys, sig, msg) {
113
  if(isObject(sig))
114
    throw new Error('signature should be base64 string, did you mean verifyObj(public, signed_obj)')
115
  return curves[getCurve(keys)].verify(
116
    u.toBuffer(keys.public || keys),
117
    u.toBuffer(sig),
118
    isBuffer(msg) ? msg : new Buffer(msg)
119
  )
120
}
121
122
// OTHER CRYTPO FUNCTIONS
123
124
exports.signObj = function (keys, hmac_key, obj) {
125
  if(!obj) obj = hmac_key, hmac_key = null
126
  var _obj = clone(obj)
127
  var b = new Buffer(JSON.stringify(_obj, null, 2))
128
  if(hmac_key) b = hmac(b, hmac_key)
129
  _obj.signature = sign(keys, b)
130
  return _obj
131
}
132
133
exports.verifyObj = function (keys, hmac_key, obj) {
134
  if(!obj) obj = hmac_key, hmac_key = null
135
  obj = clone(obj)
136
  var sig = obj.signature
137
  delete obj.signature
138
  var b = new Buffer(JSON.stringify(obj, null, 2))
139
  if(hmac_key) b = hmac(b, hmac_key)
140
  return verify(keys, sig, b)
141
}
142
143
exports.box = function (msg, recipients) {
144
  msg = new Buffer(JSON.stringify(msg))
145
146
  recipients = recipients.map(function (keys) {
147
    return sodium.crypto_sign_ed25519_pk_to_curve25519(u.toBuffer(keys.public || keys))
148
  })
149
150
  return pb.multibox(msg, recipients).toString('base64')+'.box'
151
}
152
153
exports.unbox = function (boxed, keys) {
154
  boxed = u.toBuffer(boxed)
155
  var sk = sodium.crypto_sign_ed25519_sk_to_curve25519(u.toBuffer(keys.private || keys))
156
157
  var msg = pb.multibox_open(boxed, sk)
158
  if(msg) return JSON.parse(''+msg)
159
}
160
161