Fencry uses 256 bits symmetric encryption.
     Encryption is done in stream cipher mode of operation.
     The result is displayed as hexadecimal code.
    
     Use Fencry to encrypt text to and from applications by using simple cut
     and paste. Example of use is encrypting mail and text documents.
    
     To avoid the most common stream cipher attacks, the system uses an
     open and random 256 bit key that are mixed with the secret key before
     key scheduling.
     This make sure that the same sub keys are never used more than once.
     The system also uses a simple cipher feedback system.
     After the text has been encrypted 4 times the result is split in two, where half
     of the cipher are encrypted and mixed with the other half.
     This is done 128 times before the cipher is encrypted 4 times again with the sub keys