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*Details: File format summary



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Go to:  Summary  |  Documentation  |  Signatures |  Compression  |  Character encoding  |  Rights  |  Reference files   Properties  


External signatures File extension: zip
Internal signatures
Name ZIP format
Description Local file header at BOF (with maximum offset of 4 bytes) + central file header and end of central directory near EOF. NB. The signature byte sequence is currently massaged to steer around the known PRONOM bug in the area of right fragment matching when the longest fragment is not nearest EOF. The first fragment in the EOF byte sequence has been shortened by 1 byte to ensure that the subsequent fragment is the longest. This abbreviation does not reduce the overall signature strength too much and so will hopefully not result in any false pisitive identification. When the PRONOM bug has been fixed, the "504B01" at the start of the EOF byte sequence should be extended to "504B0102", and this note reduced.
Byte sequences
Position type Absolute from BOF
Offset 0
Maximum Offset 4
Byte order  
Value 504B0304
Position type Absolute from EOF
Offset 0
Byte order Little-endian
Value 504B01{43-65531}504B0506{18-65531}
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