Backup copies of the encrypted disk header
The beginning of any encrypted disk or container created with the Cryptic Disk program has a small technical area where an encrypted header is stored that contains the master encryption key and different service information (properties of the encrypted disk, including mount options, settings of automatic actions upon disk mounting/unmounting, etc.).
The header of an encrypted disk is protected with the same encryption algorithms as the encrypted disk. For header encryption, however, the encryption key derived from the password and key files (in accordance with PKCS #5 v2) is used. Thus, in order to get access to all the encrypted data, the program needs to first obtain access to the encrypted header that contains the encryption key for the data on the disk. For this, a password and/or key files (if any) must be specified.
If the header of an encrypted disk is damaged (by some applications, viruses or due to disk misuse), accessing data turns impossible. In such a case, the only way to get access to the disk is to recover the header of the encrypted disk from the header backup copy which is stored in a special technical area located at the end of the encrypted disk. The same encryption algorithms are used for the protection of a header backup copy as for the main header, but some protection parameters are modified to ensure that the binary information blocks at the beginning and at the end of the disk differ.
The Cryptic Disk program also allows one to export the header of the encrypted disk to a file. When headers that are in-built in the encrypted disk get damaged, the user may recover them from the backup copy previously saved to a file. After the header has been recovered from the backup copy stored in the file, in order to get access to the encrypted disk, one must specify the access credentials (password and/or key files) that were valid at the moment of header export to the file.
As many as four headers are actually stored in technical areas located at the beginning and at the end of the disk. Three of those are used for hidden encrypted disks created inside an encrypted one (steganography). If the encrypted disk or container does not contain any hidden encrypted disks, the corresponding headers are simply not used. Thus, to export or recover a header of a hidden encrypted disk, one must specify the access credentials (password and/or key files) to this encrypted disk.
To call header management functions for an encrypted disk, one can use its context menu.