| ***** Field description ***** |
| |
| Reference: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT |
| |
| |
| "version made by" (2 bytes) |
| Fixed set to 0x2D |
| |
| Upper byte mapping: |
| 0 - MS-DOS and OS/2 (FAT / VFAT / FAT32 file systems) |
| 1 - Amiga 2 - OpenVMS |
| 3 - UNIX 4 - VM/CMS |
| 5 - Atari ST 6 - OS/2 H.P.F.S. |
| 7 - Macintosh 8 - Z-System |
| 9 - CP/M 10 - Windows NTFS |
| 11 - MVS (OS/390 - Z/OS) 12 - VSE |
| 13 - Acorn Risc 14 - VFAT |
| 15 - alternate MVS 16 - BeOS |
| 17 - Tandem 18 - OS/400 |
| 19 - OS X (Darwin) 20 thru 255 - unused |
| |
| Lower byte indicates the ZIP specification version |
| |
| "Version needed to extract" (2 bytes) |
| |
| Fixed set to 0x14 |
| |
| The minimum supported ZIP specification version needed |
| to extract the file, mapped as above. |
| |
| Current minimum feature versions are as defined below: |
| 1.0 - Default value |
| 1.1 - File is a volume label |
| 2.0 - File is a folder (directory) |
| 2.0 - File is compressed using Deflate compression |
| 2.0 - File is encrypted using traditional PKWARE encryption |
| 2.1 - File is compressed using Deflate64(tm) |
| 2.5 - File is compressed using PKWARE DCL Implode |
| 2.7 - File is a patch data set |
| 4.5 - File uses ZIP64 format extensions |
| 4.6 - File is compressed using BZIP2 compression* |
| 5.0 - File is encrypted using DES |
| 5.0 - File is encrypted using 3DES |
| 5.0 - File is encrypted using original RC2 encryption |
| 5.0 - File is encrypted using RC4 encryption |
| 5.1 - File is encrypted using AES encryption |
| 5.1 - File is encrypted using corrected RC2 encryption** |
| 5.2 - File is encrypted using corrected RC2-64 encryption** |
| 6.1 - File is encrypted using non-OAEP key wrapping*** |
| 6.2 - Central directory encryption |
| 6.3 - File is compressed using LZMA |
| 6.3 - File is compressed using PPMd+ |
| 6.3 - File is encrypted using Blowfish |
| 6.3 - File is encrypted using Twofish |
| |
| "general purpose bit flag" (2 bytes) |
| |
| Fixed set to 0x06 |
| |
| |
| Bit 0: If set, indicates that the file is encrypted. |
| |
| Bit 2 / 1 (For Methods 8 and 9 - Deflating) |
| 0 / 0 Normal compression option was used. |
| 0 / 1 Maximum compression option was used. |
| 1 / 0 Fast compression option was used. |
| 1 / 1 Super Fast compression option was used. |
| |
| Bit 3: fields crc-32, compressed size and uncompressed size are zero |
| in the local header. |
| |
| Bit 4: enhanced deflating. |
| |
| Bit 5: compressed patched data. |
| |
| Bit 6: Strong encryption. |
| |
| Bit 7 / 8 / 9 / 10: Currently unused. |
| |
| Bit 11: Language encoding flag (using UTF-8). |
| |
| Bit 12: enhanced compression. |
| |
| Bit 13: encrypting the Central Directory to indicate |
| selected data values in the Local Header are masked to |
| hide their actual values. |
| |
| Bit 14 / 15 / 16: Reserved by PKWARE. |
| |
| |
| "compression method" |
| Fixed set to 0x08 |
| |
| 0 - The file is stored (no compression) |
| 1 - The file is Shrunk |
| 2 - The file is Reduced with compression factor 1 |
| 3 - The file is Reduced with compression factor 2 |
| 4 - The file is Reduced with compression factor 3 |
| 5 - The file is Reduced with compression factor 4 |
| 6 - The file is Imploded |
| 7 - Reserved for Tokenizing compression algorithm |
| 8 - The file is Deflated |
| 9 - Enhanced Deflating using Deflate64(tm) |
| 10 - PKWARE Data Compression Library Imploding (old IBM TERSE) |
| 11 - Reserved by PKWARE |
| 12 - File is compressed using BZIP2 algorithm |
| 13 - Reserved by PKWARE |
| 14 - LZMA (EFS) |
| 15 - Reserved by PKWARE |
| 16 - Reserved by PKWARE |
| 17 - Reserved by PKWARE |
| 18 - File is compressed using IBM TERSE (new) |
| 19 - IBM LZ77 z Architecture (PFS) |
| 97 - WavPack compressed data |
| 98 - PPMd version I, Rev 1 |
| |
| |
| "date and time fields": (2 bytes each) |
| Fixed set to 0x0000 |
| |
| The date and time are encoded in standard MS-DOS format. |
| |
| "CRC-32": (4 bytes) |
| Calculated |
| |
| |
| "compressed size": (4 bytes) |
| data buffer size |
| |
| |
| "uncompressed size": (4 bytes) |
| Calculated |
| |
| |
| "file name length": (2 bytes) |
| Calculated |
| |
| |
| "extra field length": (2 bytes) |
| Fixed set to 0x0000 |
| |
| |
| "file comment length": (2 bytes) |
| Fixed set to 0x0000 |
| |
| |
| "disk number start": (2 bytes) |
| Fixed set to 0x0000 |
| |
| |
| "internal file attributes": (2 bytes) |
| Fixed set to 0x0000 |
| |
| Bit 0 file is apparently an ASCII or text file. |
| |
| Bits 1 are reserved for use by PKWARE. |
| |
| Bits 2 a 4 byte variable record length control field precedes each |
| logical record indicating the length of the record. |
| |
| |
| "external file attributes": (4 bytes) |
| Fixed set to 0x0000 |
| |
| the low order byte is the MS-DOS directory attribute byte. |
| |
| |
| "relative offset of local header": (4 bytes) |
| Calculated |
| |
| This is the offset from the start of the first disk on |
| which this file appears, to where the local header should |
| be found. |
| |
| |
| "file name": (Variable) |
| Copied |
| |
| Name of the file, with optional relative path. |
| All slashes MUST be forward slashes '/' |
| |
| |
| "file comment": (Variable) |
| Not used |
| |
| |
| "number of this disk": (2 bytes) |
| Fixed set to 0x0000 |
| |
| |
| "number of the disk with the start of the central directory": (2 bytes) |
| Fixed set to 0x0000 |
| |
| |
| "total number of entries in the central dir": (2 bytes) |
| Calculated |
| |
| The number of central directory entries on this disk. |
| |
| |
| "size of the central directory": (4 bytes) |
| Calculated |
| |
| The size (in bytes) of the entire central directory. |
| |
| |
| "offset of start of central directory" (4 bytes) |
| Calculated |
| |
| Offset of the start of the central directory in the file |
| |
| |
| ".ZIP file comment length": (2 bytes) |
| Calculated |
| |
| |
| The length of the comment for this .ZIP file. |
| |
| ".ZIP file comment": (Variable) |
| Set fix to "Created by Corinthia" |
| |
| The comment for this .ZIP file. |
| |
| |
| "zip64 extensible data sector" (variable size) |
| Not used |
| |
| |
| "extra field": (Variable) |
| Not used |
| |
| |
