Notifications
Clear all

hashing empty CD

8 Posts
5 Users
0 Reactions
481 Views
(@yunus)
Estimable Member
Joined: 17 years ago
Posts: 178
Topic starter  

Hello all,

Empty CD-R's are not recognized as physical and logical drives by Encase, FTK etc. so they do not seem to be hashed just like a hard drive can be done.

But but some other software like "Recover my files" seem to be producing a hash value for empty CD, which does not sound all right to me. Since the CD-R has not been burned, there may not be any sectors to hash.

What do you think?

Regards


   
Quote
(@mscotgrove)
Prominent Member
Joined: 17 years ago
Posts: 940
 

How long is the image file that Recover my files produces.

It may be a zero length file, and your hash may be for a zero length file


   
ReplyQuote
(@yunus)
Estimable Member
Joined: 17 years ago
Posts: 178
Topic starter  

"The imager" from Getdataback seems to produce a hash a value. However, like you said, it is seemingly an image file, however it is not a real image and it is 2 KB in size.

But as for the hash value which comes on screen, we have made futher tests on how it is created. We have tried with other empty CD's and a blue-ray, they all seem to produce same hash value.

So, it is not a real hashing process.


   
ReplyQuote
PaulSanderson
(@paulsanderson)
Honorable Member
Joined: 19 years ago
Posts: 651
 

What is the hash value?


   
ReplyQuote
jaclaz
(@jaclaz)
Illustrious Member
Joined: 18 years ago
Posts: 5133
 

What is the hash value?

Like would it begin with da39 … or d41d … ? wink
http//superuser.com/questions/557925/how-can-zero-byte-files-generate-a-hash-value
http//stackoverflow.com/questions/10909976/why-do-seemingly-empty-files-and-strings-produce-md5sums

Only seemingly OT
http//www.forensicfocus.com/Forums/viewtopic/p=6535731/#6535731
http//www.edenprime.com/software/epAllZeroHashCalculator.htm

jaclaz


   
ReplyQuote
(@yunus)
Estimable Member
Joined: 17 years ago
Posts: 178
Topic starter  

Paulsanderson,

The image file that Recover my files produces is 2.00 KB in size and 4.00 KB in size (on disk). And the hash value is 5FE4E4ABD0F5E7162F71542AA2B7ADE9.


   
ReplyQuote
watcher
(@watcher)
Estimable Member
Joined: 19 years ago
Posts: 125
 

Granted that any given tool may produce "something", that something doesn't always have real meaning.

In the case of a NON-empty CD or DVD, I'm not aware of a reliable tool to make a forensic copy or hash. There are a number of tools for examining the original media, and a number of tools for reliably copying selected types of CD/DVDs, but nothing I know of to copy or hash an arbitrary CD/DVD.

Am I missing something?


   
ReplyQuote
(@mscotgrove)
Prominent Member
Joined: 17 years ago
Posts: 940
 

In the case of a NON-empty CD or DVD, I'm not aware of a reliable tool to make a forensic copy or hash. There are a number of tools for examining the original media, and a number of tools for reliably copying selected types of CD/DVDs, but nothing I know of to copy or hash an arbitrary CD/DVD.

Why are you so concerned about a hash value. As far as I am concerned, a hash value is only to indicate that the data is the same or different to the time the hash was taken.

The important part of the question is which sectors can be read.

CD/DVD readers are normally controlled by information stored in 'service' tracks on the CD. ie, if the CD thinks it has 0x4000 sectors written, it will not allow access to sector 0x4001. An initialized RW disk will not allow reading of any sectors


   
ReplyQuote
Share: