//======================================================================== // // Decrypt.cc // // Copyright 1996-2003 Glyph & Cog, LLC // //======================================================================== #include #ifdef USE_GCC_PRAGMAS #pragma implementation #endif #include #include "gmem.h" #include "Decrypt.h" static void rc4InitKey(Guchar *key, int keyLen, Guchar *state); static Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c); static void aesKeyExpansion(DecryptAESState *s, Guchar *objKey, int objKeyLen); static void aesDecryptBlock(DecryptAESState *s, Guchar *in, GBool last); static void md5(Guchar *msg, int msgLen, Guchar *digest); static Guchar passwordPad[32] = { 0x28, 0xbf, 0x4e, 0x5e, 0x4e, 0x75, 0x8a, 0x41, 0x64, 0x00, 0x4e, 0x56, 0xff, 0xfa, 0x01, 0x08, 0x2e, 0x2e, 0x00, 0xb6, 0xd0, 0x68, 0x3e, 0x80, 0x2f, 0x0c, 0xa9, 0xfe, 0x64, 0x53, 0x69, 0x7a }; //------------------------------------------------------------------------ // Decrypt //------------------------------------------------------------------------ GBool Decrypt::makeFileKey(int encVersion, int encRevision, int keyLength, GString *ownerKey, GString *userKey, int permissions, GString *fileID, GString *ownerPassword, GString *userPassword, Guchar *fileKey, GBool encryptMetadata, GBool *ownerPasswordOk) { Guchar test[32], test2[32]; GString *userPassword2; Guchar fState[256]; Guchar tmpKey[16]; Guchar fx, fy; int len, i, j; // try using the supplied owner password to generate the user password *ownerPasswordOk = gFalse; if (ownerPassword) { len = ownerPassword->getLength(); if (len < 32) { memcpy(test, ownerPassword->getCString(), len); memcpy(test + len, passwordPad, 32 - len); } else { memcpy(test, ownerPassword->getCString(), 32); } md5(test, 32, test); if (encRevision == 3) { for (i = 0; i < 50; ++i) { md5(test, 16, test); } } if (encRevision == 2) { rc4InitKey(test, keyLength, fState); fx = fy = 0; for (i = 0; i < 32; ++i) { test2[i] = rc4DecryptByte(fState, &fx, &fy, ownerKey->getChar(i)); } } else { memcpy(test2, ownerKey->getCString(), 32); for (i = 19; i >= 0; --i) { for (j = 0; j < keyLength; ++j) { tmpKey[j] = test[j] ^ i; } rc4InitKey(tmpKey, keyLength, fState); fx = fy = 0; for (j = 0; j < 32; ++j) { test2[j] = rc4DecryptByte(fState, &fx, &fy, test2[j]); } } } userPassword2 = new GString((char *)test2, 32); if (makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey, permissions, fileID, userPassword2, fileKey, encryptMetadata)) { *ownerPasswordOk = gTrue; delete userPassword2; return gTrue; } delete userPassword2; } // try using the supplied user password return makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey, permissions, fileID, userPassword, fileKey, encryptMetadata); } GBool Decrypt::makeFileKey2(int /*encVersion*/, int encRevision, int keyLength, GString *ownerKey, GString *userKey, int permissions, GString *fileID, GString *userPassword, Guchar *fileKey, GBool encryptMetadata) { Guchar *buf; Guchar test[32]; Guchar fState[256]; Guchar tmpKey[16]; Guchar fx, fy; int len, i, j; GBool ok; // generate file key buf = (Guchar *)gmalloc(72 + fileID->getLength()); if (userPassword) { len = userPassword->getLength(); if (len < 32) { memcpy(buf, userPassword->getCString(), len); memcpy(buf + len, passwordPad, 32 - len); } else { memcpy(buf, userPassword->getCString(), 32); } } else { memcpy(buf, passwordPad, 32); } memcpy(buf + 32, ownerKey->getCString(), 32); buf[64] = permissions & 0xff; buf[65] = (permissions >> 8) & 0xff; buf[66] = (permissions >> 16) & 0xff; buf[67] = (permissions >> 24) & 0xff; memcpy(buf + 68, fileID->getCString(), fileID->getLength()); len = 68 + fileID->getLength(); if (!encryptMetadata) { buf[len++] = 0xff; buf[len++] = 0xff; buf[len++] = 0xff; buf[len++] = 0xff; } md5(buf, len, fileKey); if (encRevision == 3) { for (i = 0; i < 50; ++i) { md5(fileKey, keyLength, fileKey); } } // test user password if (encRevision == 2) { rc4InitKey(fileKey, keyLength, fState); fx = fy = 0; for (i = 0; i < 32; ++i) { test[i] = rc4DecryptByte(fState, &fx, &fy, userKey->getChar(i)); } ok = memcmp(test, passwordPad, 32) == 0; } else if (encRevision == 3) { memcpy(test, userKey->getCString(), 32); for (i = 19; i >= 0; --i) { for (j = 0; j < keyLength; ++j) { tmpKey[j] = fileKey[j] ^ i; } rc4InitKey(tmpKey, keyLength, fState); fx = fy = 0; for (j = 0; j < 32; ++j) { test[j] = rc4DecryptByte(fState, &fx, &fy, test[j]); } } memcpy(buf, passwordPad, 32); memcpy(buf + 32, fileID->getCString(), fileID->getLength()); md5(buf, 32 + fileID->getLength(), buf); ok = memcmp(test, buf, 16) == 0; } else { ok = gFalse; } gfree(buf); return ok; } //------------------------------------------------------------------------ // DecryptStream //------------------------------------------------------------------------ DecryptStream::DecryptStream(Stream *strA, Guchar *fileKey, CryptAlgorithm algoA, int keyLength, int objNum, int objGen): FilterStream(strA) { int n, i; algo = algoA; // construct object key for (i = 0; i < keyLength; ++i) { objKey[i] = fileKey[i]; } objKey[keyLength] = objNum & 0xff; objKey[keyLength + 1] = (objNum >> 8) & 0xff; objKey[keyLength + 2] = (objNum >> 16) & 0xff; objKey[keyLength + 3] = objGen & 0xff; objKey[keyLength + 4] = (objGen >> 8) & 0xff; if (algo == cryptAES) { objKey[keyLength + 5] = 0x73; // 's' objKey[keyLength + 6] = 0x41; // 'A' objKey[keyLength + 7] = 0x6c; // 'l' objKey[keyLength + 8] = 0x54; // 'T' n = keyLength + 9; } else { n = keyLength + 5; } md5(objKey, n, objKey); if ((objKeyLength = keyLength + 5) > 16) { objKeyLength = 16; } } DecryptStream::~DecryptStream() { delete str; } void DecryptStream::reset() { int i; str->reset(); switch (algo) { case cryptRC4: state.rc4.x = state.rc4.y = 0; rc4InitKey(objKey, objKeyLength, state.rc4.state); state.rc4.buf = EOF; break; case cryptAES: aesKeyExpansion(&state.aes, objKey, objKeyLength); for (i = 0; i < 16; ++i) { state.aes.cbc[i] = str->getChar(); } state.aes.bufIdx = 16; break; } } int DecryptStream::getChar() { Guchar in[16]; int c, i; c = EOF; // make gcc happy switch (algo) { case cryptRC4: if (state.rc4.buf == EOF) { c = str->getChar(); if (c != EOF) { state.rc4.buf = rc4DecryptByte(state.rc4.state, &state.rc4.x, &state.rc4.y, (Guchar)c); } } c = state.rc4.buf; state.rc4.buf = EOF; break; case cryptAES: if (state.aes.bufIdx == 16) { for (i = 0; i < 16; ++i) { if ((c = str->getChar()) == EOF) { return EOF; } in[i] = (Guchar)c; } aesDecryptBlock(&state.aes, in, str->lookChar() == EOF); } if (state.aes.bufIdx == 16) { c = EOF; } else { c = state.aes.buf[state.aes.bufIdx++]; } break; } return c; } int DecryptStream::lookChar() { Guchar in[16]; int c, i; c = EOF; // make gcc happy switch (algo) { case cryptRC4: if (state.rc4.buf == EOF) { c = str->getChar(); if (c != EOF) { state.rc4.buf = rc4DecryptByte(state.rc4.state, &state.rc4.x, &state.rc4.y, (Guchar)c); } } c = state.rc4.buf; break; case cryptAES: if (state.aes.bufIdx == 16) { for (i = 0; i < 16; ++i) { if ((c = str->getChar()) == EOF) { return EOF; } in[i] = c; } aesDecryptBlock(&state.aes, in, str->lookChar() == EOF); } if (state.aes.bufIdx == 16) { c = EOF; } else { c = state.aes.buf[state.aes.bufIdx]; } break; } return c; } GBool DecryptStream::isBinary(GBool last) { return str->isBinary(last); } //------------------------------------------------------------------------ // RC4-compatible decryption //------------------------------------------------------------------------ static void rc4InitKey(Guchar *key, int keyLen, Guchar *state) { Guchar index1, index2; Guchar t; int i; for (i = 0; i < 256; ++i) state[i] = i; index1 = index2 = 0; for (i = 0; i < 256; ++i) { index2 = (key[index1] + state[i] + index2) % 256; t = state[i]; state[i] = state[index2]; state[index2] = t; index1 = (index1 + 1) % keyLen; } } static Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c) { Guchar x1, y1, tx, ty; x1 = *x = (*x + 1) % 256; y1 = *y = (state[*x] + *y) % 256; tx = state[x1]; ty = state[y1]; state[x1] = ty; state[y1] = tx; return c ^ state[(tx + ty) % 256]; } //------------------------------------------------------------------------ // AES decryption //------------------------------------------------------------------------ static Guchar sbox[256] = { 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; static Guchar invSbox[256] = { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }; static Guint rcon[11] = { 0x00000000, // unused 0x01000000, 0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000, 0x40000000, 0x80000000, 0x1b000000, 0x36000000 }; static inline Guint subWord(Guint x) { return (sbox[x >> 24] << 24) | (sbox[(x >> 16) & 0xff] << 16) | (sbox[(x >> 8) & 0xff] << 8) | sbox[x & 0xff]; } static inline Guint rotWord(Guint x) { return ((x << 8) & 0xffffffff) | (x >> 24); } static inline void invSubBytes(Guchar *state) { int i; for (i = 0; i < 16; ++i) { state[i] = invSbox[state[i]]; } } static inline void invShiftRows(Guchar *state) { Guchar t; t = state[7]; state[7] = state[6]; state[6] = state[5]; state[5] = state[4]; state[4] = t; t = state[8]; state[8] = state[10]; state[10] = t; t = state[9]; state[9] = state[11]; state[11] = t; t = state[12]; state[12] = state[13]; state[13] = state[14]; state[14] = state[15]; state[15] = t; } // {09} \cdot s static inline Guchar mul09(Guchar s) { Guchar s2, s4, s8; s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1); s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1); s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1); return s ^ s8; } // {0b} \cdot s static inline Guchar mul0b(Guchar s) { Guchar s2, s4, s8; s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1); s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1); s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1); return s ^ s2 ^ s8; } // {0d} \cdot s static inline Guchar mul0d(Guchar s) { Guchar s2, s4, s8; s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1); s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1); s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1); return s ^ s4 ^ s8; } // {0e} \cdot s static inline Guchar mul0e(Guchar s) { Guchar s2, s4, s8; s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1); s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1); s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1); return s2 ^ s4 ^ s8; } static inline void invMixColumns(Guchar *state) { int c; Guchar s0, s1, s2, s3; for (c = 0; c < 4; ++c) { s0 = state[c]; s1 = state[4+c]; s2 = state[8+c]; s3 = state[12+c]; state[c] = mul0e(s0) ^ mul0b(s1) ^ mul0d(s2) ^ mul09(s3); state[4+c] = mul09(s0) ^ mul0e(s1) ^ mul0b(s2) ^ mul0d(s3); state[8+c] = mul0d(s0) ^ mul09(s1) ^ mul0e(s2) ^ mul0b(s3); state[12+c] = mul0b(s0) ^ mul0d(s1) ^ mul09(s2) ^ mul0e(s3); } } static inline void invMixColumnsW(Guint *w) { int c; Guchar s0, s1, s2, s3; for (c = 0; c < 4; ++c) { s0 = w[c] >> 24; s1 = w[c] >> 16; s2 = w[c] >> 8; s3 = w[c]; w[c] = ((mul0e(s0) ^ mul0b(s1) ^ mul0d(s2) ^ mul09(s3)) << 24) | ((mul09(s0) ^ mul0e(s1) ^ mul0b(s2) ^ mul0d(s3)) << 16) | ((mul0d(s0) ^ mul09(s1) ^ mul0e(s2) ^ mul0b(s3)) << 8) | (mul0b(s0) ^ mul0d(s1) ^ mul09(s2) ^ mul0e(s3)); } } static inline void addRoundKey(Guchar *state, Guint *w) { int c; for (c = 0; c < 4; ++c) { state[c] ^= w[c] >> 24; state[4+c] ^= w[c] >> 16; state[8+c] ^= w[c] >> 8; state[12+c] ^= w[c]; } } static void aesKeyExpansion(DecryptAESState *s, Guchar *objKey, int /*objKeyLen*/) { Guint temp; int i, round; //~ this assumes objKeyLen == 16 for (i = 0; i < 4; ++i) { s->w[i] = (objKey[4*i] << 24) + (objKey[4*i+1] << 16) + (objKey[4*i+2] << 8) + objKey[4*i+3]; } for (i = 4; i < 44; ++i) { temp = s->w[i-1]; if (!(i & 3)) { temp = subWord(rotWord(temp)) ^ rcon[i/4]; } s->w[i] = s->w[i-4] ^ temp; } for (round = 1; round <= 9; ++round) { invMixColumnsW(&s->w[round * 4]); } } static void aesDecryptBlock(DecryptAESState *s, Guchar *in, GBool last) { int c, round, n, i; // initial state for (c = 0; c < 4; ++c) { s->state[c] = in[4*c]; s->state[4+c] = in[4*c+1]; s->state[8+c] = in[4*c+2]; s->state[12+c] = in[4*c+3]; } // round 0 addRoundKey(s->state, &s->w[10 * 4]); // rounds 1-9 for (round = 9; round >= 1; --round) { invSubBytes(s->state); invShiftRows(s->state); invMixColumns(s->state); addRoundKey(s->state, &s->w[round * 4]); } // round 10 invSubBytes(s->state); invShiftRows(s->state); addRoundKey(s->state, &s->w[0]); // CBC for (c = 0; c < 4; ++c) { s->buf[4*c] = s->state[c] ^ s->cbc[4*c]; s->buf[4*c+1] = s->state[4+c] ^ s->cbc[4*c+1]; s->buf[4*c+2] = s->state[8+c] ^ s->cbc[4*c+2]; s->buf[4*c+3] = s->state[12+c] ^ s->cbc[4*c+3]; } // save the input block for the next CBC for (i = 0; i < 16; ++i) { s->cbc[i] = in[i]; } // remove padding s->bufIdx = 0; if (last) { n = s->buf[15]; for (i = 15; i >= n; --i) { s->buf[i] = s->buf[i-n]; } s->bufIdx = n; } } //------------------------------------------------------------------------ // MD5 message digest //------------------------------------------------------------------------ // this works around a bug in older Sun compilers static inline Gulong rotateLeft(Gulong x, int r) { x &= 0xffffffff; return ((x << r) | (x >> (32 - r))) & 0xffffffff; } static inline Gulong md5Round1(Gulong a, Gulong b, Gulong c, Gulong d, Gulong Xk, Gulong s, Gulong Ti) { return b + rotateLeft((a + ((b & c) | (~b & d)) + Xk + Ti), s); } static inline Gulong md5Round2(Gulong a, Gulong b, Gulong c, Gulong d, Gulong Xk, Gulong s, Gulong Ti) { return b + rotateLeft((a + ((b & d) | (c & ~d)) + Xk + Ti), s); } static inline Gulong md5Round3(Gulong a, Gulong b, Gulong c, Gulong d, Gulong Xk, Gulong s, Gulong Ti) { return b + rotateLeft((a + (b ^ c ^ d) + Xk + Ti), s); } static inline Gulong md5Round4(Gulong a, Gulong b, Gulong c, Gulong d, Gulong Xk, Gulong s, Gulong Ti) { return b + rotateLeft((a + (c ^ (b | ~d)) + Xk + Ti), s); } static void md5(Guchar *msg, int msgLen, Guchar *digest) { Gulong x[16]; Gulong a, b, c, d, aa, bb, cc, dd; int n64; int i, j, k; // compute number of 64-byte blocks // (length + pad byte (0x80) + 8 bytes for length) n64 = (msgLen + 1 + 8 + 63) / 64; // initialize a, b, c, d a = 0x67452301; b = 0xefcdab89; c = 0x98badcfe; d = 0x10325476; // loop through blocks k = 0; for (i = 0; i < n64; ++i) { // grab a 64-byte block for (j = 0; j < 16 && k < msgLen - 3; ++j, k += 4) x[j] = (((((msg[k+3] << 8) + msg[k+2]) << 8) + msg[k+1]) << 8) + msg[k]; if (i == n64 - 1) { if (k == msgLen - 3) x[j] = 0x80000000 + (((msg[k+2] << 8) + msg[k+1]) << 8) + msg[k]; else if (k == msgLen - 2) x[j] = 0x800000 + (msg[k+1] << 8) + msg[k]; else if (k == msgLen - 1) x[j] = 0x8000 + msg[k]; else x[j] = 0x80; ++j; while (j < 16) x[j++] = 0; x[14] = msgLen << 3; } // save a, b, c, d aa = a; bb = b; cc = c; dd = d; // round 1 a = md5Round1(a, b, c, d, x[0], 7, 0xd76aa478); d = md5Round1(d, a, b, c, x[1], 12, 0xe8c7b756); c = md5Round1(c, d, a, b, x[2], 17, 0x242070db); b = md5Round1(b, c, d, a, x[3], 22, 0xc1bdceee); a = md5Round1(a, b, c, d, x[4], 7, 0xf57c0faf); d = md5Round1(d, a, b, c, x[5], 12, 0x4787c62a); c = md5Round1(c, d, a, b, x[6], 17, 0xa8304613); b = md5Round1(b, c, d, a, x[7], 22, 0xfd469501); a = md5Round1(a, b, c, d, x[8], 7, 0x698098d8); d = md5Round1(d, a, b, c, x[9], 12, 0x8b44f7af); c = md5Round1(c, d, a, b, x[10], 17, 0xffff5bb1); b = md5Round1(b, c, d, a, x[11], 22, 0x895cd7be); a = md5Round1(a, b, c, d, x[12], 7, 0x6b901122); d = md5Round1(d, a, b, c, x[13], 12, 0xfd987193); c = md5Round1(c, d, a, b, x[14], 17, 0xa679438e); b = md5Round1(b, c, d, a, x[15], 22, 0x49b40821); // round 2 a = md5Round2(a, b, c, d, x[1], 5, 0xf61e2562); d = md5Round2(d, a, b, c, x[6], 9, 0xc040b340); c = md5Round2(c, d, a, b, x[11], 14, 0x265e5a51); b = md5Round2(b, c, d, a, x[0], 20, 0xe9b6c7aa); a = md5Round2(a, b, c, d, x[5], 5, 0xd62f105d); d = md5Round2(d, a, b, c, x[10], 9, 0x02441453); c = md5Round2(c, d, a, b, x[15], 14, 0xd8a1e681); b = md5Round2(b, c, d, a, x[4], 20, 0xe7d3fbc8); a = md5Round2(a, b, c, d, x[9], 5, 0x21e1cde6); d = md5Round2(d, a, b, c, x[14], 9, 0xc33707d6); c = md5Round2(c, d, a, b, x[3], 14, 0xf4d50d87); b = md5Round2(b, c, d, a, x[8], 20, 0x455a14ed); a = md5Round2(a, b, c, d, x[13], 5, 0xa9e3e905); d = md5Round2(d, a, b, c, x[2], 9, 0xfcefa3f8); c = md5Round2(c, d, a, b, x[7], 14, 0x676f02d9); b = md5Round2(b, c, d, a, x[12], 20, 0x8d2a4c8a); // round 3 a = md5Round3(a, b, c, d, x[5], 4, 0xfffa3942); d = md5Round3(d, a, b, c, x[8], 11, 0x8771f681); c = md5Round3(c, d, a, b, x[11], 16, 0x6d9d6122); b = md5Round3(b, c, d, a, x[14], 23, 0xfde5380c); a = md5Round3(a, b, c, d, x[1], 4, 0xa4beea44); d = md5Round3(d, a, b, c, x[4], 11, 0x4bdecfa9); c = md5Round3(c, d, a, b, x[7], 16, 0xf6bb4b60); b = md5Round3(b, c, d, a, x[10], 23, 0xbebfbc70); a = md5Round3(a, b, c, d, x[13], 4, 0x289b7ec6); d = md5Round3(d, a, b, c, x[0], 11, 0xeaa127fa); c = md5Round3(c, d, a, b, x[3], 16, 0xd4ef3085); b = md5Round3(b, c, d, a, x[6], 23, 0x04881d05); a = md5Round3(a, b, c, d, x[9], 4, 0xd9d4d039); d = md5Round3(d, a, b, c, x[12], 11, 0xe6db99e5); c = md5Round3(c, d, a, b, x[15], 16, 0x1fa27cf8); b = md5Round3(b, c, d, a, x[2], 23, 0xc4ac5665); // round 4 a = md5Round4(a, b, c, d, x[0], 6, 0xf4292244); d = md5Round4(d, a, b, c, x[7], 10, 0x432aff97); c = md5Round4(c, d, a, b, x[14], 15, 0xab9423a7); b = md5Round4(b, c, d, a, x[5], 21, 0xfc93a039); a = md5Round4(a, b, c, d, x[12], 6, 0x655b59c3); d = md5Round4(d, a, b, c, x[3], 10, 0x8f0ccc92); c = md5Round4(c, d, a, b, x[10], 15, 0xffeff47d); b = md5Round4(b, c, d, a, x[1], 21, 0x85845dd1); a = md5Round4(a, b, c, d, x[8], 6, 0x6fa87e4f); d = md5Round4(d, a, b, c, x[15], 10, 0xfe2ce6e0); c = md5Round4(c, d, a, b, x[6], 15, 0xa3014314); b = md5Round4(b, c, d, a, x[13], 21, 0x4e0811a1); a = md5Round4(a, b, c, d, x[4], 6, 0xf7537e82); d = md5Round4(d, a, b, c, x[11], 10, 0xbd3af235); c = md5Round4(c, d, a, b, x[2], 15, 0x2ad7d2bb); b = md5Round4(b, c, d, a, x[9], 21, 0xeb86d391); // increment a, b, c, d a += aa; b += bb; c += cc; d += dd; } // break digest into bytes digest[0] = (Guchar)(a & 0xff); digest[1] = (Guchar)((a >>= 8) & 0xff); digest[2] = (Guchar)((a >>= 8) & 0xff); digest[3] = (Guchar)((a >>= 8) & 0xff); digest[4] = (Guchar)(b & 0xff); digest[5] = (Guchar)((b >>= 8) & 0xff); digest[6] = (Guchar)((b >>= 8) & 0xff); digest[7] = (Guchar)((b >>= 8) & 0xff); digest[8] = (Guchar)(c & 0xff); digest[9] = (Guchar)((c >>= 8) & 0xff); digest[10] = (Guchar)((c >>= 8) & 0xff); digest[11] = (Guchar)((c >>= 8) & 0xff); digest[12] = (Guchar)(d & 0xff); digest[13] = (Guchar)((d >>= 8) & 0xff); digest[14] = (Guchar)((d >>= 8) & 0xff); digest[15] = (Guchar)((d >>= 8) & 0xff); }