Is there hidden information in MAT files?

I need to do a complete check of the content of a MAT file. My plan was to load it into the MATLAB workspace and interrogate each variable in turn. Can MAT files contain inform that would not be accessable directly in this way? If so, how would I access it?

[Steven Lord]

What does a "complete check" entail? What are you looking for? What's your goal?

[Troy Skousen]

I want to make sure that no propriatary information is hidden in the file somewhere.

[Walter Roberson]

hidden accidentally or deliberately ? If deliberately then information can always be encoded in subtle ways such as the details of variables marked as deleted.

You can reduce risks by loading the variables and saving them to a new file .

[Troy Skousen]

Deliberately. Making a fresh copy of the data I want is a good idea.

Answer 1

[Walter Roberson]

Yes, there is additional information about the size and compression status of each variable , and about the date of creation of the file and about the kind of system (os family ) and the endianness.

specifications are published for MATLAB 5.0 file format . The 7.0 file format is pretty similar . You can find tools in fex for debugging these files.

However 7.3 are aa different format related to hdf5 with some undocumented changes.