[b]md5sum on windows DLL from same source different[/b]

[johnlopez2000]

I am doing an MD5SUM on 2 DLLs. They are both supposedly from the same source code.

I am charged to determine if the binary of the delivered DLL is equivalent with the source included also.

I copied the original DLL to xUtils_orig.dll

I compiled a new DLL from the above source: xUtils.dll

I did: md5sum *.dll

The MD5 checksums are different.

Does that mean that they are different in that they were from different versions of source code, or is there a digital signature in a DLL that is used in the registry and is generated afresh when a new compile happens, thereby making the checksum of the files different even though the same source was used to create both.

Thanks for you help.


John Lopez
Enterprise PDM Architect
john.l.lopez@goodrich.com

 

[strongm]

Are you quite sure that you used exactly the same compiler/linker flags and options?

 

[johnlopez2000]

yup-

I renamed DLL#2 and did a new compile.

Did an MD5SUM of all 3 and got a different number again.


hummmmmmmmmmm!

John Lopez
Enterprise PDM Architect
john.l.lopez@goodrich.com

 

[trollacious]

If compile date/time is included in the file, or if there's a (micro)version change, you'll get a different numbers because the file will have different data in it. Have you tried a character-by-character file compare like some text and binary file editors have?

Lee

 

[johnlopez2000]

Hi trollacious -
no I haven't.

does DIFF do that? I thought this would only be for ascii file comparison.

Do you have a binary editor you use that does this? I have hexedit, but I think it does not have a compare function. I'll check.

Thanks

John Lopez
Enterprise PDM Architect
john.l.lopez@goodrich.com

 

[johnlopez2000]

... note - I did a visual compare of the 2 DLLs in a hex editor, and found a small difference at address 0000c8-0000c9

fileA = 7f 55
fileB = f7 3f

not really sure why the difference???

John Lopez
Enterprise PDM Architect
john.l.lopez@goodrich.com