why 2 zip files of same file have different checksum

I am doing zip of a file at different time one by one,and after that when I calculate the checksum of both the zip files I am getting different checksum for both files. (The file is same , I am not changing the file)

Can anyone suggest me or explain me why this happens?

Is there any solution to this ?

Is it possible to get the zip files with same checksum.

[383 byte] By [sipina] at [2007-10-3 3:21:24]

«« Integrating Openoffice -Searching /Replacing string within delimiter
»» how to show superscript in ,java application?

# 1

I would perform checksums on the source files, as opposed to a zipped up version of the files....

How big is the checksum ?32 bit ?

I've seen checksum clashes on arbitrary strings, for a CRC32 algorithm, after scanning in a few hundred thousand records.... completely different strings, approx 200 chars wide.

If you need real unique id's for files, maybe try something like MD5, which has a lot more checksum bits than a standard CRC 32 checksum.

regards,

Owen

omcgoverna at 2007-7-14 21:13:40 >

top of Java-index,Java Essentials,Java Programming...

# 2

The zip files include their own timestamp information, so I'm not surprized with their checksums being different...

Franck_Lefevrea at 2007-7-14 21:13:40 >

Java programming resources: FAQs, tutorials, compiler and browser download sites, documentation, books lists, IDEs, etc.

why 2 zip files of same file have different checksum

Java Essentials New Topic

Java Essentials Hot Topic

Java Essentials

All Classified