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1 /* crypt.h -- base code for crypt/uncrypt ZIPfile | 1 /* crypt.h -- base code for crypt/uncrypt ZIPfile |
2 | 2 |
3 | 3 |
4 Version 1.01e, February 12th, 2005 | 4 Version 1.01e, February 12th, 2005 |
5 | 5 |
6 Copyright (C) 1998-2005 Gilles Vollant | 6 Copyright (C) 1998-2005 Gilles Vollant |
7 | 7 |
8 This code is a modified version of crypting code in Infozip distribution | 8 This code is a modified version of crypting code in Infozip distribution |
9 | 9 |
10 The encryption/decryption parts of this source code (as opposed to the | 10 The encryption/decryption parts of this source code (as opposed to the |
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25 The new AES encryption added on Zip format by Winzip (see the page | 25 The new AES encryption added on Zip format by Winzip (see the page |
26 http://www.winzip.com/aes_info.htm ) and PKWare PKZip 5.x Strong | 26 http://www.winzip.com/aes_info.htm ) and PKWare PKZip 5.x Strong |
27 Encryption is not supported. | 27 Encryption is not supported. |
28 */ | 28 */ |
29 | 29 |
30 #define CRC32(c, b) ((*(pcrc_32_tab+(((int)(c) ^ (b)) & 0xff))) ^ ((c) >> 8)) | 30 #define CRC32(c, b) ((*(pcrc_32_tab+(((int)(c) ^ (b)) & 0xff))) ^ ((c) >> 8)) |
31 | 31 |
32 /*********************************************************************** | 32 /*********************************************************************** |
33 * Return the next byte in the pseudo-random sequence | 33 * Return the next byte in the pseudo-random sequence |
34 */ | 34 */ |
35 static int decrypt_byte(unsigned long* pkeys, const unsigned long* pcrc_32_tab) | 35 static int decrypt_byte(unsigned long* pkeys, const z_crc_t* pcrc_32_tab) |
36 { | 36 { |
37 unsigned temp; /* POTENTIAL BUG: temp*(temp^1) may overflow in an | 37 unsigned temp; /* POTENTIAL BUG: temp*(temp^1) may overflow in an |
38 * unpredictable manner on 16-bit systems; not a problem | 38 * unpredictable manner on 16-bit systems; not a problem |
39 * with any known compiler so far, though */ | 39 * with any known compiler so far, though */ |
40 | 40 |
41 temp = ((unsigned)(*(pkeys+2)) & 0xffff) | 2; | 41 temp = ((unsigned)(*(pkeys+2)) & 0xffff) | 2; |
42 return (int)(((temp * (temp ^ 1)) >> 8) & 0xff); | 42 return (int)(((temp * (temp ^ 1)) >> 8) & 0xff); |
43 } | 43 } |
44 | 44 |
45 /*********************************************************************** | 45 /*********************************************************************** |
46 * Update the encryption keys with the next byte of plain text | 46 * Update the encryption keys with the next byte of plain text |
47 */ | 47 */ |
48 static int update_keys(unsigned long* pkeys,const unsigned long* pcrc_32_tab,int
c) | 48 static int update_keys(unsigned long* pkeys,const z_crc_t* pcrc_32_tab,int c) |
49 { | 49 { |
50 (*(pkeys+0)) = CRC32((*(pkeys+0)), c); | 50 (*(pkeys+0)) = CRC32((*(pkeys+0)), c); |
51 (*(pkeys+1)) += (*(pkeys+0)) & 0xff; | 51 (*(pkeys+1)) += (*(pkeys+0)) & 0xff; |
52 (*(pkeys+1)) = (*(pkeys+1)) * 134775813L + 1; | 52 (*(pkeys+1)) = (*(pkeys+1)) * 134775813L + 1; |
53 { | 53 { |
54 register int keyshift = (int)((*(pkeys+1)) >> 24); | 54 register int keyshift = (int)((*(pkeys+1)) >> 24); |
55 (*(pkeys+2)) = CRC32((*(pkeys+2)), keyshift); | 55 (*(pkeys+2)) = CRC32((*(pkeys+2)), keyshift); |
56 } | 56 } |
57 return c; | 57 return c; |
58 } | 58 } |
59 | 59 |
60 | 60 |
61 /*********************************************************************** | 61 /*********************************************************************** |
62 * Initialize the encryption keys and the random header according to | 62 * Initialize the encryption keys and the random header according to |
63 * the given password. | 63 * the given password. |
64 */ | 64 */ |
65 static void init_keys(const char* passwd,unsigned long* pkeys,const unsigned lon
g* pcrc_32_tab) | 65 static void init_keys(const char* passwd,unsigned long* pkeys,const z_crc_t* pcr
c_32_tab) |
66 { | 66 { |
67 *(pkeys+0) = 305419896L; | 67 *(pkeys+0) = 305419896L; |
68 *(pkeys+1) = 591751049L; | 68 *(pkeys+1) = 591751049L; |
69 *(pkeys+2) = 878082192L; | 69 *(pkeys+2) = 878082192L; |
70 while (*passwd != '\0') { | 70 while (*passwd != '\0') { |
71 update_keys(pkeys,pcrc_32_tab,(int)*passwd); | 71 update_keys(pkeys,pcrc_32_tab,(int)*passwd); |
72 passwd++; | 72 passwd++; |
73 } | 73 } |
74 } | 74 } |
75 | 75 |
76 #define zdecode(pkeys,pcrc_32_tab,c) \ | 76 #define zdecode(pkeys,pcrc_32_tab,c) \ |
77 (update_keys(pkeys,pcrc_32_tab,c ^= decrypt_byte(pkeys,pcrc_32_tab))) | 77 (update_keys(pkeys,pcrc_32_tab,c ^= decrypt_byte(pkeys,pcrc_32_tab))) |
78 | 78 |
79 #define zencode(pkeys,pcrc_32_tab,c,t) \ | 79 #define zencode(pkeys,pcrc_32_tab,c,t) \ |
80 (t=decrypt_byte(pkeys,pcrc_32_tab), update_keys(pkeys,pcrc_32_tab,c), t^(c)) | 80 (t=decrypt_byte(pkeys,pcrc_32_tab), update_keys(pkeys,pcrc_32_tab,c), t^(c)) |
81 | 81 |
82 #ifdef INCLUDECRYPTINGCODE_IFCRYPTALLOWED | 82 #ifdef INCLUDECRYPTINGCODE_IFCRYPTALLOWED |
83 | 83 |
84 #define RAND_HEAD_LEN 12 | 84 #define RAND_HEAD_LEN 12 |
85 /* "last resort" source for second part of crypt seed pattern */ | 85 /* "last resort" source for second part of crypt seed pattern */ |
86 # ifndef ZCR_SEED2 | 86 # ifndef ZCR_SEED2 |
87 # define ZCR_SEED2 3141592654UL /* use PI as default pattern */ | 87 # define ZCR_SEED2 3141592654UL /* use PI as default pattern */ |
88 # endif | 88 # endif |
89 | 89 |
90 static int crypthead(const char* passwd, /* password string */ | 90 static int crypthead(const char* passwd, /* password string */ |
91 unsigned char* buf, /* where to write header */ | 91 unsigned char* buf, /* where to write header */ |
92 int bufSize, | 92 int bufSize, |
93 unsigned long* pkeys, | 93 unsigned long* pkeys, |
94 const unsigned long* pcrc_32_tab, | 94 const z_crc_t* pcrc_32_tab, |
95 unsigned long crcForCrypting) | 95 unsigned long crcForCrypting) |
96 { | 96 { |
97 int n; /* index in random header */ | 97 int n; /* index in random header */ |
98 int t; /* temporary */ | 98 int t; /* temporary */ |
99 int c; /* random byte */ | 99 int c; /* random byte */ |
100 unsigned char header[RAND_HEAD_LEN-2]; /* random header */ | 100 unsigned char header[RAND_HEAD_LEN-2]; /* random header */ |
101 static unsigned calls = 0; /* ensure different random header each time */ | 101 static unsigned calls = 0; /* ensure different random header each time */ |
102 | 102 |
103 if (bufSize<RAND_HEAD_LEN) | 103 if (bufSize<RAND_HEAD_LEN) |
104 return 0; | 104 return 0; |
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122 for (n = 0; n < RAND_HEAD_LEN-2; n++) | 122 for (n = 0; n < RAND_HEAD_LEN-2; n++) |
123 { | 123 { |
124 buf[n] = (unsigned char)zencode(pkeys, pcrc_32_tab, header[n], t); | 124 buf[n] = (unsigned char)zencode(pkeys, pcrc_32_tab, header[n], t); |
125 } | 125 } |
126 buf[n++] = (unsigned char)zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >
> 16) & 0xff, t); | 126 buf[n++] = (unsigned char)zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >
> 16) & 0xff, t); |
127 buf[n++] = (unsigned char)zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >
> 24) & 0xff, t); | 127 buf[n++] = (unsigned char)zencode(pkeys, pcrc_32_tab, (int)(crcForCrypting >
> 24) & 0xff, t); |
128 return n; | 128 return n; |
129 } | 129 } |
130 | 130 |
131 #endif | 131 #endif |
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