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);