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
|
/*
This is where the magic happens
*/
var WidevineCrypto = {};
(function() {
// The public 2048-bit RSA key Widevine uses for Chrome devices in L3
WidevineCrypto.chromeRSAPublicKey =
`-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtdHcRBiDWWxdJyKDLTPO9OTapumVnW+9g6k3RSflM0CESFEufZUJGC73UKe9e+u789HVZT04pB5or3WB0XOx
aOibJklLBkd7Yfn1OndVrenMKTE1F4/6jg5rmwyv4qFQ1u8M/ThZUrAgb8pTmKfb9vrv1V8AApwVzcQg3s48eESnKjBU99Vk8alPTjPSfOgoTDluGxQONWiwCaMwftNs
YrOzlde+V3UOb5FVzPcrOmaERfyujV3h4sHGRbTCsqYVwMalO7hmNmtemwt0xBuf5Juia7t1scuJypQ8lI1iEsB+JZVo3Uovfa9nNX0gl5TAq1tAh6M55/ttpWAirWHv
CQIDAQAB
-----END PUBLIC KEY-----`;
// The private 2048-bit RSA key Widevine uses for authenticating Chrome devices in L3
// Extracted by applying some mathematical tricks to Araxan's white-box algorithm
WidevineCrypto.chromeRSAPrivateKey =
`-----BEGIN PRIVATE KEY-----
MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC10dxEGINZbF0nIoMtM8705Nqm6ZWdb72DqTdFJ+UzQIRIUS59lQkYLvdQp71767vz0dVlPTikHmiv
dYHRc7Fo6JsmSUsGR3th+fU6d1Wt6cwpMTUXj/qODmubDK/ioVDW7wz9OFlSsCBvylOYp9v2+u/VXwACnBXNxCDezjx4RKcqMFT31WTxqU9OM9J86ChMOW4bFA41aLAJ
ozB+02xis7OV175XdQ5vkVXM9ys6ZoRF/K6NXeHiwcZFtMKyphXAxqU7uGY2a16bC3TEG5/km6Jru3Wxy4nKlDyUjWISwH4llWjdSi99r2c1fSCXlMCrW0CHoznn+22l
YCKtYe8JAgMBAAECggEAGOPDJvFCHd43PFG9qlTyylR/2CSWzigLRfhGsClfd24oDaxLVHav+YcIZRqpVkr1flGlyEeittjQ1OAdptoTGbzp7EpRQmlLqyRoHRpT+MxO
Hf91+KVFk+fGdEG+3CPgKKQt34Y0uByTPCpy2i10b7F3Xnq0Sicq1vG33DhYT9A/DRIjYr8Y0AVovq0VDjWqA1FW5OO9p7vky6e+PDMjSHucQ+uaLzVZSc7vWOh0tH5M
0GVk17YpBiB/iTpw4zBUIcaneQX3eaIfSCDHK0SCD6IRF7kl+uORzvWqiWlGzpdG2B96uyP4hd3WoPcZntM79PKm4dAotdgmalbueFJfpwKBgQDUy0EyA9Fq0aPF4LID
HqDPduIm4hEAZf6sQLd8Fe6ywM4p9KOEVx7YPaFxQHFSgIiWXswildPJl8Cg5cM2EyMU1tdn5xaR4VIDk8e2JEDfhPtaWskpJp2rU2wHvAXOeAES7UFMrkhKVqqVOdbo
IhlLdcYp5KxiJ3mwINSSO94ShwKBgQDavJvF+c8AINfCaMocUX0knXz+xCwdP430GoPQCHa1rUj5bZ3qn3XMwSWa57J4x3pVhYmgJv4jpEK+LBULFezNLV5N4C7vH63a
Zo4OF7IUedFBS5B508yAq7RiPhN2VOC8LRdDh5oqnFufjafF82y9d+/czCrVIG43D+KO2j4F7wKBgDg/HZWF0tYEYeDNGuCeOO19xBt5B/tt+lo3pQhkl7qiIhyO8KXr
jVilOcZAvXOMTA5LMnQ13ExeE2m0MdxaRJyeiUOKnrmisFYHuvNXM9qhQPtKIgABmA2QOG728SX5LHd/RRJqwur7a42UQ00Krlr235F1Q2eSfaTjmKyqrHGDAoGAOTrd
2ueoZFUzfnciYlRj1L+r45B6JlDpmDOTx0tfm9sx26j1h1yfWqoyZ5w1kupGNLgSsSdimPqyR8WK3/KlmW1EXkXIoeH8/8aTZlaGzlqtCFN4ApgKyqOiN44cU3qTrkhx
7MY+7OUqB83tVpqBGfWWeYOltUud6qQqV8v8LFsCgYEAnOq+Ls83CaHIWCjpVfiWC+R7mqW+ql1OGtoaajtA4AzhXzX8HIXpYjupPBlXlQ1FFfPem6jwa1UTZf8CpIb8
pPULAN9ZRrxG8V+bvkZWVREPTZj7xPCwPaZHNKoAmi3Dbv7S5SEYDbBX/NyPCLE4sj/AgTPbUsUtaiw5TvrPsFE=
-----END PRIVATE KEY-----`;
WidevineCrypto.initializeKeys = async function()
{
// load the device RSA keys for various purposes
this.publicKeyEncrypt = await crypto.subtle.importKey('spki', PEM2Binary(this.chromeRSAPublicKey), {name: 'RSA-OAEP', hash: { name: 'SHA-1' },}, true, ['encrypt']);
this.publicKeyVerify = await crypto.subtle.importKey('spki', PEM2Binary(this.chromeRSAPublicKey), {name: 'RSA-PSS', hash: { name: 'SHA-1' },}, true, ['verify']);
this.privateKeyDecrypt = await crypto.subtle.importKey('pkcs8', PEM2Binary(this.chromeRSAPrivateKey), {name: 'RSA-OAEP', hash: { name: 'SHA-1' },}, true, ['decrypt']);
var isRSAGood = await isRSAConsistent(this.publicKeyEncrypt, this.privateKeyDecrypt);
if (!isRSAGood)
{
throw "Can't verify RSA keys consistency; This means the public key does not match the private key!";
}
this.keysInitialized = true;
}
WidevineCrypto.decryptContentKey = async function(licenseRequest, licenseResponse)
{
licenseRequest = SignedMessage.read(new Pbf(licenseRequest));
licenseResponse = SignedMessage.read(new Pbf(licenseResponse));
if (licenseRequest.type != SignedMessage.MessageType.LICENSE_REQUEST.value) return;
license = License.read(new Pbf(licenseResponse.msg));
if (!this.keysInitialized) await this.initializeKeys();
// make sure the signature in the license request validates under the private key
var signatureVerified = await window.crypto.subtle.verify({name: "RSA-PSS", saltLength: 20,}, this.publicKeyVerify,
licenseRequest.signature, licenseRequest.msg)
if (!signatureVerified)
{
console.log("Can't verify license request signature; either the platform is wrong or the key has changed!");
return null;
}
// decrypt the session key
var sessionKey = await crypto.subtle.decrypt({name: "RSA-OAEP"}, this.privateKeyDecrypt, licenseResponse.session_key);
// calculate context_enc
var encoder = new TextEncoder();
var keySize = 128;
var context_enc = concatBuffers([[0x01], encoder.encode("ENCRYPTION"), [0x00], licenseRequest.msg, intToBuffer(keySize)]);
// calculate encrypt_key using CMAC
var encryptKey = wordToByteArray(
CryptoJS.CMAC(arrayToWordArray(new Uint8Array(sessionKey)),
arrayToWordArray(new Uint8Array(context_enc))).words);
// iterate the keys we got to find those we want to decrypt (the content key(s))
var contentKeys = []
for (currentKey of license.key)
{
if (currentKey.type != License.KeyContainer.KeyType.CONTENT.value) continue;
var keyId = currentKey.id;
var keyData = currentKey.key.slice(0, 16);
var keyIv = currentKey.iv.slice(0, 16);
// finally decrypt the content key
var decryptedKey = wordToByteArray(
CryptoJS.AES.decrypt({ ciphertext: arrayToWordArray(keyData) }, arrayToWordArray(encryptKey), { iv: arrayToWordArray(keyIv) }).words);
contentKeys.push(decryptedKey);
console.log("WidevineDecryptor: Found key: " + toHexString(decryptedKey) + " (KID=" + toHexString(keyId) + ")");
}
return contentKeys[0];
}
//
// Helper functions
//
async function isRSAConsistent(publicKey, privateKey)
{
// See if the data is correctly decrypted after encryption
var testData = new Uint8Array([0x41, 0x42, 0x43, 0x44]);
var encryptedData = await crypto.subtle.encrypt({name: "RSA-OAEP"}, publicKey, testData);
var testDecryptedData = await crypto.subtle.decrypt({name: "RSA-OAEP"}, privateKey, encryptedData);
return areBuffersEqual(testData, testDecryptedData);
}
function areBuffersEqual(buf1, buf2)
{
if (buf1.byteLength != buf2.byteLength) return false;
var dv1 = new Int8Array(buf1);
var dv2 = new Int8Array(buf2);
for (var i = 0 ; i != buf1.byteLength ; i++)
{
if (dv1[i] != dv2[i]) return false;
}
return true;
}
function concatBuffers(arrays)
{
// Get the total length of all arrays.
let length = 0;
arrays.forEach(item => {
length += item.length;
});
// Create a new array with total length and merge all source arrays.
let mergedArray = new Uint8Array(length);
let offset = 0;
arrays.forEach(item => {
mergedArray.set(new Uint8Array(item), offset);
offset += item.length;
});
return mergedArray;
}
// CryptoJS format to byte array
function wordToByteArray(wordArray)
{
var byteArray = [], word, i, j;
for (i = 0; i < wordArray.length; ++i) {
word = wordArray[i];
for (j = 3; j >= 0; --j) {
byteArray.push((word >> 8 * j) & 0xFF);
}
}
return byteArray;
}
// byte array to CryptoJS format
function arrayToWordArray(u8Array)
{
var words = [], i = 0, len = u8Array.length;
while (i < len) {
words.push(
(u8Array[i++] << 24) |
(u8Array[i++] << 16) |
(u8Array[i++] << 8) |
(u8Array[i++])
);
}
return {
sigBytes: len,
words: words
};
}
const toHexString = bytes => bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), '');
const intToBuffer = num =>
{
let b = new ArrayBuffer(4);
new DataView(b).setUint32(0, num);
return Array.from(new Uint8Array(b));
}
function PEM2Binary(pem)
{
var encoded = '';
var lines = pem.split('\n');
for (var i = 0; i < lines.length; i++) {
if (lines[i].indexOf('-----') < 0) {
encoded += lines[i];
}
}
var byteStr = atob(encoded);
var bytes = new Uint8Array(byteStr.length);
for (var i = 0; i < byteStr.length; i++) {
bytes[i] = byteStr.charCodeAt(i);
}
return bytes.buffer;
}
}());
|
