of the software can then safely skip this file, and
find the next file or header. This field will be 0
length in version 1.0.
In order to allow different programs and different types
of information to be stored in the 'extra' field in .ZIP
files, the following structure should be used for all
programs storing data in this field:
header1+data1 + header2+data2 . . .
Each header should consist of:
Header ID - 2 bytes
Data Size - 2 bytes
Note: all fields stored in Intel low-byte/high-byte order.
The Header ID field indicates the type of data that is in
the following data block.
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
0x000a NTFS
0x000c OpenVMS
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 Third party mappings commonly used are:
0x07c8 Macintosh
0x2605 ZipIt Macintosh
0x2705 ZipIt Macintosh 1.3.5+
0x2805 ZipIt Macintosh 1.3.5+
0x334d Info-ZIP Macintosh
0x4341 Acorn/SparkFS
0x4453 Windows NT security descriptor (binary ACL)
0x4704 VM/CMS
0x470f MVS
0x4b46 FWKCS MD5 (see below)
0x4c41 OS/2 access control list (text ACL)
0x4d49 Info-ZIP OpenVMS
0x4f4c Xceed original location extra field
0x5356 AOS/VS (ACL)
0x5455 extended timestamp
0x554e Xceed unicode extra field
0x5855 Info-ZIP Unix (original, also OS/2, NT, etc)
0x6542 BeOS/BeBox
0x756e ASi Unix
0x7855 Info-ZIP Unix (new)
0xfd4a SMS/QDOS
