1
//========================================================================
5
// Copyright 1996-2002 Glyph & Cog, LLC
7
//========================================================================
11
#ifdef USE_GCC_PRAGMAS
12
#pragma implementation
18
static void rc4InitKey(Guchar *key, int keyLen, Guchar *state);
19
static Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c);
20
static void md5(Guchar *msg, int msgLen, Guchar *digest);
22
static Guchar passwordPad[32] = {
23
0x28, 0xbf, 0x4e, 0x5e, 0x4e, 0x75, 0x8a, 0x41,
24
0x64, 0x00, 0x4e, 0x56, 0xff, 0xfa, 0x01, 0x08,
25
0x2e, 0x2e, 0x00, 0xb6, 0xd0, 0x68, 0x3e, 0x80,
26
0x2f, 0x0c, 0xa9, 0xfe, 0x64, 0x53, 0x69, 0x7a
29
//------------------------------------------------------------------------
31
//------------------------------------------------------------------------
33
Decrypt::Decrypt(Guchar *fileKey, int keyLength, int objNum, int objGen) {
36
// construct object key
37
for (i = 0; i < keyLength; ++i) {
38
objKey[i] = fileKey[i];
40
objKey[keyLength] = objNum & 0xff;
41
objKey[keyLength + 1] = (objNum >> 8) & 0xff;
42
objKey[keyLength + 2] = (objNum >> 16) & 0xff;
43
objKey[keyLength + 3] = objGen & 0xff;
44
objKey[keyLength + 4] = (objGen >> 8) & 0xff;
45
md5(objKey, keyLength + 5, objKey);
47
// set up for decryption
49
if ((objKeyLength = keyLength + 5) > 16) {
52
rc4InitKey(objKey, objKeyLength, state);
55
void Decrypt::reset() {
57
rc4InitKey(objKey, objKeyLength, state);
60
Guchar Decrypt::decryptByte(Guchar c) {
61
return rc4DecryptByte(state, &x, &y, c);
64
GBool Decrypt::makeFileKey(int encVersion, int encRevision, int keyLength,
65
GString *ownerKey, GString *userKey,
66
int permissions, GString *fileID,
67
GString *ownerPassword, GString *userPassword,
68
Guchar *fileKey, GBool *ownerPasswordOk) {
69
Guchar test[32], test2[32];
70
GString *userPassword2;
76
// try using the supplied owner password to generate the user password
78
len = ownerPassword->getLength();
80
memcpy(test, ownerPassword->getCString(), len);
81
memcpy(test + len, passwordPad, 32 - len);
83
memcpy(test, ownerPassword->getCString(), 32);
86
memcpy(test, passwordPad, 32);
89
if (encRevision == 3) {
90
for (i = 0; i < 50; ++i) {
94
if (encRevision == 2) {
95
rc4InitKey(test, keyLength, fState);
97
for (i = 0; i < 32; ++i) {
98
test2[i] = rc4DecryptByte(fState, &fx, &fy, ownerKey->getChar(i));
101
memcpy(test2, ownerKey->getCString(), 32);
102
for (i = 19; i >= 0; --i) {
103
for (j = 0; j < keyLength; ++j) {
104
tmpKey[j] = test[j] ^ i;
106
rc4InitKey(tmpKey, keyLength, fState);
108
for (j = 0; j < 32; ++j) {
109
test2[j] = rc4DecryptByte(fState, &fx, &fy, test2[j]);
113
userPassword2 = new GString((char *)test2, 32);
114
if (makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey,
115
permissions, fileID, userPassword2, fileKey)) {
116
*ownerPasswordOk = gTrue;
117
delete userPassword2;
120
*ownerPasswordOk = gFalse;
121
delete userPassword2;
123
// try using the supplied user password
124
return makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey,
125
permissions, fileID, userPassword, fileKey);
128
GBool Decrypt::makeFileKey2(int encVersion, int encRevision, int keyLength,
129
GString *ownerKey, GString *userKey,
130
int permissions, GString *fileID,
131
GString *userPassword, Guchar *fileKey) {
141
buf = (Guchar *)gmalloc(68 + fileID->getLength());
143
len = userPassword->getLength();
145
memcpy(buf, userPassword->getCString(), len);
146
memcpy(buf + len, passwordPad, 32 - len);
148
memcpy(buf, userPassword->getCString(), 32);
151
memcpy(buf, passwordPad, 32);
153
memcpy(buf + 32, ownerKey->getCString(), 32);
154
buf[64] = permissions & 0xff;
155
buf[65] = (permissions >> 8) & 0xff;
156
buf[66] = (permissions >> 16) & 0xff;
157
buf[67] = (permissions >> 24) & 0xff;
158
memcpy(buf + 68, fileID->getCString(), fileID->getLength());
159
md5(buf, 68 + fileID->getLength(), fileKey);
160
if (encRevision == 3) {
161
for (i = 0; i < 50; ++i) {
162
md5(fileKey, keyLength, fileKey);
166
// test user password
167
if (encRevision == 2) {
168
rc4InitKey(fileKey, keyLength, fState);
170
for (i = 0; i < 32; ++i) {
171
test[i] = rc4DecryptByte(fState, &fx, &fy, userKey->getChar(i));
173
ok = memcmp(test, passwordPad, 32) == 0;
174
} else if (encRevision == 3) {
175
memcpy(test, userKey->getCString(), 32);
176
for (i = 19; i >= 0; --i) {
177
for (j = 0; j < keyLength; ++j) {
178
tmpKey[j] = fileKey[j] ^ i;
180
rc4InitKey(tmpKey, keyLength, fState);
182
for (j = 0; j < 32; ++j) {
183
test[j] = rc4DecryptByte(fState, &fx, &fy, test[j]);
186
memcpy(buf, passwordPad, 32);
187
memcpy(buf + 32, fileID->getCString(), fileID->getLength());
188
md5(buf, 32 + fileID->getLength(), buf);
189
ok = memcmp(test, buf, 16) == 0;
198
//------------------------------------------------------------------------
199
// RC4-compatible decryption
200
//------------------------------------------------------------------------
202
static void rc4InitKey(Guchar *key, int keyLen, Guchar *state) {
203
Guchar index1, index2;
207
for (i = 0; i < 256; ++i)
210
for (i = 0; i < 256; ++i) {
211
index2 = (key[index1] + state[i] + index2) % 256;
213
state[i] = state[index2];
215
index1 = (index1 + 1) % keyLen;
219
static Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c) {
220
Guchar x1, y1, tx, ty;
222
x1 = *x = (*x + 1) % 256;
223
y1 = *y = (state[*x] + *y) % 256;
228
return c ^ state[(tx + ty) % 256];
231
//------------------------------------------------------------------------
232
// MD5 message digest
233
//------------------------------------------------------------------------
235
// this works around a bug in older Sun compilers
236
static inline Gulong rotateLeft(Gulong x, int r) {
238
return ((x << r) | (x >> (32 - r))) & 0xffffffff;
241
static inline Gulong md5Round1(Gulong a, Gulong b, Gulong c, Gulong d,
242
Gulong Xk, Gulong s, Gulong Ti) {
243
return b + rotateLeft((a + ((b & c) | (~b & d)) + Xk + Ti), s);
246
static inline Gulong md5Round2(Gulong a, Gulong b, Gulong c, Gulong d,
247
Gulong Xk, Gulong s, Gulong Ti) {
248
return b + rotateLeft((a + ((b & d) | (c & ~d)) + Xk + Ti), s);
251
static inline Gulong md5Round3(Gulong a, Gulong b, Gulong c, Gulong d,
252
Gulong Xk, Gulong s, Gulong Ti) {
253
return b + rotateLeft((a + (b ^ c ^ d) + Xk + Ti), s);
256
static inline Gulong md5Round4(Gulong a, Gulong b, Gulong c, Gulong d,
257
Gulong Xk, Gulong s, Gulong Ti) {
258
return b + rotateLeft((a + (c ^ (b | ~d)) + Xk + Ti), s);
261
static void md5(Guchar *msg, int msgLen, Guchar *digest) {
263
Gulong a, b, c, d, aa, bb, cc, dd;
267
// compute number of 64-byte blocks
268
// (length + pad byte (0x80) + 8 bytes for length)
269
n64 = (msgLen + 1 + 8 + 63) / 64;
271
// initialize a, b, c, d
277
// loop through blocks
279
for (i = 0; i < n64; ++i) {
281
// grab a 64-byte block
282
for (j = 0; j < 16 && k < msgLen - 3; ++j, k += 4)
283
x[j] = (((((msg[k+3] << 8) + msg[k+2]) << 8) + msg[k+1]) << 8) + msg[k];
286
x[j] = 0x80000000 + (((msg[k+2] << 8) + msg[k+1]) << 8) + msg[k];
287
else if (k == msgLen - 2)
288
x[j] = 0x800000 + (msg[k+1] << 8) + msg[k];
289
else if (k == msgLen - 1)
290
x[j] = 0x8000 + msg[k];
306
a = md5Round1(a, b, c, d, x[0], 7, 0xd76aa478);
307
d = md5Round1(d, a, b, c, x[1], 12, 0xe8c7b756);
308
c = md5Round1(c, d, a, b, x[2], 17, 0x242070db);
309
b = md5Round1(b, c, d, a, x[3], 22, 0xc1bdceee);
310
a = md5Round1(a, b, c, d, x[4], 7, 0xf57c0faf);
311
d = md5Round1(d, a, b, c, x[5], 12, 0x4787c62a);
312
c = md5Round1(c, d, a, b, x[6], 17, 0xa8304613);
313
b = md5Round1(b, c, d, a, x[7], 22, 0xfd469501);
314
a = md5Round1(a, b, c, d, x[8], 7, 0x698098d8);
315
d = md5Round1(d, a, b, c, x[9], 12, 0x8b44f7af);
316
c = md5Round1(c, d, a, b, x[10], 17, 0xffff5bb1);
317
b = md5Round1(b, c, d, a, x[11], 22, 0x895cd7be);
318
a = md5Round1(a, b, c, d, x[12], 7, 0x6b901122);
319
d = md5Round1(d, a, b, c, x[13], 12, 0xfd987193);
320
c = md5Round1(c, d, a, b, x[14], 17, 0xa679438e);
321
b = md5Round1(b, c, d, a, x[15], 22, 0x49b40821);
324
a = md5Round2(a, b, c, d, x[1], 5, 0xf61e2562);
325
d = md5Round2(d, a, b, c, x[6], 9, 0xc040b340);
326
c = md5Round2(c, d, a, b, x[11], 14, 0x265e5a51);
327
b = md5Round2(b, c, d, a, x[0], 20, 0xe9b6c7aa);
328
a = md5Round2(a, b, c, d, x[5], 5, 0xd62f105d);
329
d = md5Round2(d, a, b, c, x[10], 9, 0x02441453);
330
c = md5Round2(c, d, a, b, x[15], 14, 0xd8a1e681);
331
b = md5Round2(b, c, d, a, x[4], 20, 0xe7d3fbc8);
332
a = md5Round2(a, b, c, d, x[9], 5, 0x21e1cde6);
333
d = md5Round2(d, a, b, c, x[14], 9, 0xc33707d6);
334
c = md5Round2(c, d, a, b, x[3], 14, 0xf4d50d87);
335
b = md5Round2(b, c, d, a, x[8], 20, 0x455a14ed);
336
a = md5Round2(a, b, c, d, x[13], 5, 0xa9e3e905);
337
d = md5Round2(d, a, b, c, x[2], 9, 0xfcefa3f8);
338
c = md5Round2(c, d, a, b, x[7], 14, 0x676f02d9);
339
b = md5Round2(b, c, d, a, x[12], 20, 0x8d2a4c8a);
342
a = md5Round3(a, b, c, d, x[5], 4, 0xfffa3942);
343
d = md5Round3(d, a, b, c, x[8], 11, 0x8771f681);
344
c = md5Round3(c, d, a, b, x[11], 16, 0x6d9d6122);
345
b = md5Round3(b, c, d, a, x[14], 23, 0xfde5380c);
346
a = md5Round3(a, b, c, d, x[1], 4, 0xa4beea44);
347
d = md5Round3(d, a, b, c, x[4], 11, 0x4bdecfa9);
348
c = md5Round3(c, d, a, b, x[7], 16, 0xf6bb4b60);
349
b = md5Round3(b, c, d, a, x[10], 23, 0xbebfbc70);
350
a = md5Round3(a, b, c, d, x[13], 4, 0x289b7ec6);
351
d = md5Round3(d, a, b, c, x[0], 11, 0xeaa127fa);
352
c = md5Round3(c, d, a, b, x[3], 16, 0xd4ef3085);
353
b = md5Round3(b, c, d, a, x[6], 23, 0x04881d05);
354
a = md5Round3(a, b, c, d, x[9], 4, 0xd9d4d039);
355
d = md5Round3(d, a, b, c, x[12], 11, 0xe6db99e5);
356
c = md5Round3(c, d, a, b, x[15], 16, 0x1fa27cf8);
357
b = md5Round3(b, c, d, a, x[2], 23, 0xc4ac5665);
360
a = md5Round4(a, b, c, d, x[0], 6, 0xf4292244);
361
d = md5Round4(d, a, b, c, x[7], 10, 0x432aff97);
362
c = md5Round4(c, d, a, b, x[14], 15, 0xab9423a7);
363
b = md5Round4(b, c, d, a, x[5], 21, 0xfc93a039);
364
a = md5Round4(a, b, c, d, x[12], 6, 0x655b59c3);
365
d = md5Round4(d, a, b, c, x[3], 10, 0x8f0ccc92);
366
c = md5Round4(c, d, a, b, x[10], 15, 0xffeff47d);
367
b = md5Round4(b, c, d, a, x[1], 21, 0x85845dd1);
368
a = md5Round4(a, b, c, d, x[8], 6, 0x6fa87e4f);
369
d = md5Round4(d, a, b, c, x[15], 10, 0xfe2ce6e0);
370
c = md5Round4(c, d, a, b, x[6], 15, 0xa3014314);
371
b = md5Round4(b, c, d, a, x[13], 21, 0x4e0811a1);
372
a = md5Round4(a, b, c, d, x[4], 6, 0xf7537e82);
373
d = md5Round4(d, a, b, c, x[11], 10, 0xbd3af235);
374
c = md5Round4(c, d, a, b, x[2], 15, 0x2ad7d2bb);
375
b = md5Round4(b, c, d, a, x[9], 21, 0xeb86d391);
377
// increment a, b, c, d
384
// break digest into bytes
385
digest[0] = (Guchar)(a & 0xff);
386
digest[1] = (Guchar)((a >>= 8) & 0xff);
387
digest[2] = (Guchar)((a >>= 8) & 0xff);
388
digest[3] = (Guchar)((a >>= 8) & 0xff);
389
digest[4] = (Guchar)(b & 0xff);
390
digest[5] = (Guchar)((b >>= 8) & 0xff);
391
digest[6] = (Guchar)((b >>= 8) & 0xff);
392
digest[7] = (Guchar)((b >>= 8) & 0xff);
393
digest[8] = (Guchar)(c & 0xff);
394
digest[9] = (Guchar)((c >>= 8) & 0xff);
395
digest[10] = (Guchar)((c >>= 8) & 0xff);
396
digest[11] = (Guchar)((c >>= 8) & 0xff);
397
digest[12] = (Guchar)(d & 0xff);
398
digest[13] = (Guchar)((d >>= 8) & 0xff);
399
digest[14] = (Guchar)((d >>= 8) & 0xff);
400
digest[15] = (Guchar)((d >>= 8) & 0xff);