The following are the known types of zipfile extra fields as of thiswriting.  Extra fields are documented in PKWARE's appnote.txt and areintended to allow for backward- and forward-compatible extensions tothe zipfile format.  Multiple extra-field types may be chained together,provided that the total length of all extra-field data is less than 64KB.(In fact, PKWARE requires that the total length of the entire file header,including timestamp, file attributes, filename, comment, extra field, etc.,be no more than 64KB.)Each extra-field type (or subblock) must contain a four-byte header con-sisting of a two-byte header ID and a two-byte length (little-endian) forthe remaining data in the subblock.  If there are additional subblockswithin the extra field, the header for each one will appear immediatelyfollowing the data for the previous subblock (i.e., with no padding foralignment).All integer fields in the descriptions below are in little-endian (Intel)format unless otherwise specified.  Note that "Short" means two bytes,"Long" means four bytes, and "Long-Long" means eight bytes, regardlessof their native sizes.  Unless specifically noted, all integer fields shouldbe interpreted as unsigned (non-negative) numbers.Christian Spieler, 20040507                        -------------------------          Header ID's of 0 thru 31 are reserved for use by PKWARE.          The remaining ID's can be used by third party vendors for          proprietary usage.          The current Header ID mappings defined by PKWARE are:          0x0001        ZIP64 extended information extra field          0x0007        AV Info          0x0008        Reserved for future Unicode file name data (PFS)          0x0009        OS/2 extended attributes      (also Info-ZIP)          0x000a        NTFS (Win9x/WinNT FileTimes)          0x000c        OpenVMS                       (also Info-ZIP)          0x000d        Unix          0x000e        Reserved for file stream and fork descriptors          0x000f        Patch Descriptor          0x0014        PKCS#7 Store for X.509 Certificates          0x0015        X.509 Certificate ID and Signature for                        individual file          0x0016        X.509 Certificate ID for Central Directory          0x0017        Strong Encryption Header          0x0018        Record Management Controls          0x0019        PKCS#7 Encryption Recipient Certificate List          0x0065        IBM S/390 (Z390), AS/400 (I400) attributes                        - uncompressed          0x0066        Reserved for IBM S/390 (Z390), AS/400 (I400)                        attributes - compressed          The Header ID mappings defined by Info-ZIP and third parties are:          0x07c8        Info-ZIP Macintosh (old, J. Lee)          0x2605        ZipIt Macintosh (first version)          0x2705        ZipIt Macintosh v 1.3.5 and newer (w/o full filename)          0x2805        ZipIt Macintosh 1.3.5+          0x334d        Info-ZIP Macintosh (new, D. Haase's 'Mac3' field)          0x4154        Tandem NSK          0x4341        Acorn/SparkFS (David Pilling)          0x4453        Windows NT security descriptor (binary ACL)          0x4704        VM/CMS          0x470f        MVS          0x4854        Theos, old inofficial port          0x4b46        FWKCS MD5 (see below)          0x4c41        OS/2 access control list (text ACL)          0x4d49        Info-ZIP OpenVMS (obsolete)          0x4d63        Macintosh SmartZIP, by Macro Bambini          0x4f4c        Xceed original location extra field          0x5356        AOS/VS (binary ACL)          0x5455        extended timestamp          0x554e        Xceed unicode extra field          0x5855        Info-ZIP Unix (original; also OS/2, NT, etc.)          0x6542        BeOS (BeBox, PowerMac, etc.)          0x6854        Theos          0x7441        AtheOS (AtheOS/Syllable attributes)          0x756e        ASi Unix          0x7855        Info-ZIP Unix (new)          0xfb4a        SMS/QDOSThe following are detailed descriptions of the known extra-field block types:         -ZIP64 Extended Information Extra Field (0x0001):          ===============================================          The following is the layout of the ZIP64 extended          information "extra" block. If one of the size or          offset fields in the Local or Central directory          record is too small to hold the required data,          a ZIP64 extended information record is created.          The order of the fields in the ZIP64 extended          information record is fixed, but the fields will          only appear if the corresponding Local or Central          directory record field is set to 0xFFFF or 0xFFFFFFFF.          Note: all fields stored in Intel low-byte/high-byte order.          Value      Size       Description          -----      ----       -----------  (ZIP64) 0x0001     2 bytes    Tag for this "extra" block type          Size       2 bytes    Size of this "extra" block          Original          Size       8 bytes    Original uncompressed file size          Compressed          Size       8 bytes    Size of compressed data          Relative Header          Offset     8 bytes    Offset of local header record          Disk Start          Number     4 bytes    Number of the disk on which                                this file starts          This entry in the Local header must include BOTH original          and compressed file sizes.         -OS/2 Extended Attributes Extra Field (0x0009):          =============================================          The following is the layout of the OS/2 extended attributes "extra"          block.  (Last Revision 19960922)          Note: all fields stored in Intel low-byte/high-byte order.          Local-header version:          Value         Size        Description          -----         ----        -----------  (OS/2)  0x0009        Short       tag for this extra block type          TSize         Short       total data size for this block          BSize         Long        uncompressed EA data size          CType         Short       compression type          EACRC         Long        CRC value for uncompressed EA data          (var.)        variable    compressed EA data          Central-header version:          Value         Size        Description          -----         ----        -----------  (OS/2)  0x0009        Short       tag for this extra block type          TSize         Short       total data size for this block (4)          BSize         Long        size of uncompressed local EA data          The value of CType is interpreted according to the "compression          method" section above; i.e., 0 for stored, 8 for deflated, etc.          The OS/2 extended attribute structure (FEA2LIST) is          compressed and then stored in its entirety within this          structure.  There will only ever be one "block" of data in          the variable-length field.         -OS/2 Access Control List Extra Field:          ====================================          The following is the layout of the OS/2 ACL extra block.          (Last Revision 19960922)          Local-header version:          Value         Size        Description          -----         ----        -----------  (ACL)   0x4c41        Short       tag for this extra block type ("AL")          TSize         Short       total data size for this block          BSize         Long        uncompressed ACL data size          CType         Short       compression type          EACRC         Long        CRC value for uncompressed ACL data          (var.)        variable    compressed ACL data          Central-header version:          Value         Size        Description          -----         ----        -----------  (ACL)   0x4c41        Short       tag for this extra block type ("AL")          TSize         Short       total data size for this block (4)          BSize         Long        size of uncompressed local ACL data          The value of CType is interpreted according to the "compression          method" section above; i.e., 0 for stored, 8 for deflated, etc.          The uncompressed ACL data consist of a text header of the form          "ACL1:%hX,%hd\n", where the first field is the OS/2 ACCINFO acc_attr          member and the second is acc_count, followed by acc_count strings          of the form "%s,%hx\n", where the first field is acl_ugname (user          group name) and the second acl_access.  This block type will be          extended for other operating systems as needed.         -Windows NT Security Descriptor Extra Field (0x4453):          ===================================================          The following is the layout of the NT Security Descriptor (another          type of ACL) extra block.  (Last Revision 19960922)          Local-header version:          Value         Size        Description          -----         ----        -----------  (SD)    0x4453        Short       tag for this extra block type ("SD")          TSize         Short       total data size for this block          BSize         Long        uncompressed SD data size          Version       Byte        version of uncompressed SD data format          CType         Short       compression type          EACRC         Long        CRC value for uncompressed SD data          (var.)        variable    compressed SD data          Central-header version:          Value         Size        Description          -----         ----        -----------  (SD)    0x4453        Short       tag for this extra block type ("SD")          TSize         Short       total data size for this block (4)          BSize         Long        size of uncompressed local SD data          The value of CType is interpreted according to the "compression          method" section above; i.e., 0 for stored, 8 for deflated, etc.          Version specifies how the compressed data are to be interpreted          and allows for future expansion of this extra field type.  Currently          only version 0 is defined.          For version 0, the compressed data are to be interpreted as a single          valid Windows NT SECURITY_DESCRIPTOR data structure, in self-relative          format.         -PKWARE Win95/WinNT Extra Field (0x000a):          =======================================          The following description covers PKWARE's "NTFS" attributes          "extra" block, introduced with the release of PKZIP 2.50 for          Windows. (Last Revision 20001118)          (Note: At this time the Mtime, Atime and Ctime values may          be used on any WIN32 system.)         [Info-ZIP note: In the current implementations, this field has          a fixed total data size of 32 bytes and is only stored as local          extra field.]          Value         Size        Description          -----         ----        -----------  (NTFS)  0x000a        Short       Tag for this "extra" block type          TSize         Short       Total Data Size for this block          Reserved      Long        for future use          Tag1          Short       NTFS attribute tag value #1          Size1         Short       Size of attribute #1, in bytes          (var.)        SubSize1    Attribute #1 data          .          .          .          TagN          Short       NTFS attribute tag value #N          SizeN         Short       Size of attribute #N, in bytes          (var.)        SubSizeN    Attribute #N data          For NTFS, values for Tag1 through TagN are as follows:          (currently only one set of attributes is defined for NTFS)          Tag        Size       Description          -----      ----       -----------          0x0001     2 bytes    Tag for attribute #1          Size1      2 bytes    Size of attribute #1, in bytes (24)          Mtime      8 bytes    64-bit NTFS file last modification time          Atime      8 bytes    64-bit NTFS file last access time          Ctime      8 bytes    64-bit NTFS file creation time          The total length for this block is 28 bytes, resulting in a          fixed size value of 32 for the TSize field of the NTFS block.          The NTFS filetimes are 64-bit unsigned integers, stored in Intel          (least significant byte first) byte order. They determine the          number of 1.0E-07 seconds (1/10th microseconds!) past WinNT "epoch",          which is "01-Jan-1601 00:00:00 UTC".         -PKWARE OpenVMS Extra Field (0x000c):          ===================================          The following is the layout of PKWARE's OpenVMS attributes          "extra" block.  (Last Revision 12/17/91)          Note: all fields stored in Intel low-byte/high-byte order.          Value         Size        Description          -----         ----        -----------  (VMS)   0x000c        Short       Tag for this "extra" block type          TSize         Short       Total Data Size for this block          CRC           Long        32-bit CRC for remainder of the block          Tag1          Short       OpenVMS attribute tag value #1          Size1         Short       Size of attribute #1, in bytes