Good morning experts,

we came across a potential problem in Windows CE 4.2. One
of our customers wants to have a higher than normal
security device, running WIndows CE 4.2.

Here is what they plan to do. The only persistent storage
is a flash disk. The only file system is that flash disk
file system and that flash disk partition is marked hidden
for Windows CE by using MountFlags=1 value for IDE
profile. So user really sees no files at all, but registry
persists on that flash disk correctly.

However, the files on that hidden partition of a flash
disk are stored in encrypted form and are accessible to
customer application. Crypto API 2 is used to
encrypt/decrypt files. In case if flash disk or device is
stolen, it would not be possible to retrieve data from
such flash disk.

Customer has reported recently, that this approach would
work well if a flash disk is formatted FAT and partition
is notrmal, i.e. not hidden.

However, Crypto API 2 function CryptDecrypt() returns an
error [bad data], when exact same code is used for files
on hidden partition, as described above. When partition
not marked as hidden, it works as customer wants.

Does anybody have a clue ? Any help is highly appreciated.

Sincerely

Sergei