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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
|
var jwt = {};
var JWTInternals = (function() {
// convert a base64url string to hex
var b64urlmap="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
function b64urltohex(s) {
var ret = ""
var i;
var k = 0; // b64 state, 0-3
var slop;
for(i = 0; i < s.length; ++i) {
var v = b64urlmap.indexOf(s.charAt(i));
if(v < 0) continue;
if(k == 0) {
ret += int2char(v >> 2);
slop = v & 3;
k = 1;
}
else if(k == 1) {
ret += int2char((slop << 2) | (v >> 4));
slop = v & 0xf;
k = 2;
}
else if(k == 2) {
ret += int2char(slop);
ret += int2char(v >> 2);
slop = v & 3;
k = 3;
}
else {
ret += int2char((slop << 2) | (v >> 4));
ret += int2char(v & 0xf);
k = 0;
}
}
if(k == 1)
ret += int2char(slop << 2);
return ret;
}
function base64urlencode(arg)
{
var s = window.btoa(arg); // Standard base64 encoder
s = s.split('=')[0]; // Remove any trailing '='s
s = s.replace(/\+/g, '-'); // 62nd char of encoding
s = s.replace(/\//g, '_'); // 63rd char of encoding
// TODO optimize this; we can do much better
return s;
}
function base64urldecode(arg)
{
var s = arg;
s = s.replace(/-/g, '+'); // 62nd char of encoding
s = s.replace(/_/g, '/'); // 63rd char of encoding
switch (s.length % 4) // Pad with trailing '='s
{
case 0: break; // No pad chars in this case
case 2: s += "=="; break; // Two pad chars
case 3: s += "="; break; // One pad char
default: throw new InputException("Illegal base64url string!");
}
return window.atob(s); // Standard base64 decoder
}
function NoSuchAlgorithmException(message) {
this.message = message;
this.toString = function() { return "No such algorithm: "+this.message; };
}
function NotImplementedException(message) {
this.message = message;
this.toString = function() { return "Not implemented: "+this.message; };
}
function InputException(message) {
this.message = message;
this.toString = function() { return "Malformed input: "+this.message; };
}
function HMACAlgorithm(hash, key)
{
if (hash == "sha256") {
this.hash = sjcl.hash.sha256;
} else {
throw new NoSuchAlgorithmException("HMAC does not support hash " + hash);
}
this.key = sjcl.codec.utf8String.toBits(key);
}
HMACAlgorithm.prototype =
{
update: function _update(data)
{
this.data = data;
},
finalize: function _finalize()
{
},
sign: function _sign()
{
var hmac = new sjcl.misc.hmac(this.key, this.hash);
var result = hmac.encrypt(this.data);
return base64urlencode(window.atob(sjcl.codec.base64.fromBits(result)));
},
verify: function _verify(sig)
{
var hmac = new sjcl.misc.hmac(this.key, this.hash);
var result = hmac.encrypt(this.data);
return base64urlencode(window.atob(sjcl.codec.base64.fromBits(result))) == sig;
}
}
function RSASHAAlgorithm(hash, keyPEM)
{
if (hash == "sha1") {
this.hash = "sha1";
} else if (hash == "sha256") {
this.hash = "sha256";
} else {
throw new NoSuchAlgorithmException("JWT algorithm: " + hash);
}
this.keyPEM = keyPEM;
}
RSASHAAlgorithm.prototype =
{
update: function _update(data)
{
this.data = data;
},
finalize: function _finalize()
{
},
sign: function _sign()
{
var rsa = new RSAKey();
rsa.readPrivateKeyFromPEMString(this.keyPEM);
var hSig = rsa.signString(this.data, this.hash);
return base64urlencode(base64urldecode(hex2b64(hSig))); // TODO replace this with hex2b64urlencode!
},
verify: function _verify(sig)
{
var result = this.keyPEM.verifyString(this.data, b64urltohex(sig));
return result;
}
}
function WebToken(objectStr, algorithm)
{
this.objectStr = objectStr;
this.pkAlgorithm = algorithm;
}
var WebTokenParser = {
parse: function _parse(input)
{
var parts = input.split(".");
if (parts.length != 3) {
throw new MalformedWebToken("Must have three parts");
}
var token = new WebToken();
token.headerSegment = parts[0];
token.payloadSegment = parts[1];
token.cryptoSegment = parts[2];
token.pkAlgorithm = base64urldecode(parts[0]);
return token;
}
}
function jsonObj(strOrObject)
{
if (typeof strOrObject == "string") {
return JSON.parse(strOrObject);
}
return strOrObject;
}
function constructAlgorithm(jwtAlgStr, key)
{
if ("ES256" === jwtAlgStr) {
throw new NotImplementedException("ECDSA-SHA256 not yet implemented");
} else if ("ES384" === jwtAlgStr) {
throw new NotImplementedException("ECDSA-SHA384 not yet implemented");
} else if ("ES512" === jwtAlgStr) {
throw new NotImplementedException("ECDSA-SHA512 not yet implemented");
} else if ("HS256" === jwtAlgStr) {
return new HMACAlgorithm("sha256", key);
} else if ("HS384" === jwtAlgStr) {
throw new NotImplementedException("HMAC-SHA384 not yet implemented");
} else if ("HS512" === jwtAlgStr) {
throw new NotImplementedException("HMAC-SHA512 not yet implemented");
} else if ("RS256" === jwtAlgStr) {
return new RSASHAAlgorithm("sha256", key);
} else if ("RS384" === jwtAlgStr) {
throw new NotImplementedException("RSA-SHA384 not yet implemented");
} else if ("RS512" === jwtAlgStr) {
throw new NotImplementedException("RSA-SHA512 not yet implemented");
} else {
throw new NoSuchAlgorithmException("Unknown algorithm: " + jwtAlgStr);
}
}
WebToken.prototype =
{
serialize: function _serialize(key)
{
var header = jsonObj(this.pkAlgorithm);
var jwtAlgStr = header.alg;
var algorithm = constructAlgorithm(jwtAlgStr, key);
var algBytes = base64urlencode(this.pkAlgorithm);
var jsonBytes = base64urlencode(this.objectStr);
var stringToSign = algBytes + "." + jsonBytes;
algorithm.update(stringToSign);
var digestValue = algorithm.finalize();
var signatureValue = algorithm.sign();
return algBytes + "." + jsonBytes + "." + signatureValue;
},
verify: function _verify(key)
{
var header = jsonObj(this.pkAlgorithm);
var jwtAlgStr = header.alg;
var algorithm = constructAlgorithm(jwtAlgStr, key);
algorithm.update(this.headerSegment + "." + this.payloadSegment);
algorithm.finalize();
return algorithm.verify(this.cryptoSegment);
}
}
jwt.WebToken = WebToken;
jwt.WebTokenParser = WebTokenParser;
jwt.base64urlencode = base64urlencode;
jwt.base64urldecode = base64urldecode;
})();
|
