Can I use my own MIFARE® DESFire encryption and card summation for RFID media?

This is possible in principle. In KentixONE, you can choose between Kentix-specific encryption and your own (custom) encryption (MIFARE® DESFire application).

Why does Kentix identification media use a standard key and UID rather than a sequentially printed number?
The Kentix RFID tokens (key fob, card, etc.) are all delivered with a Kentix specific MIFARE® DESFire key and without imprinting a sequential number. This greatly simplifies handling for customers with smaller and medium-sized systems.

The customization of the application is done via a configuration file in the following format:

mifare_desfire	
app_id	“0xa1b2c3d4”
file_number	1
file_offset	0
file_length	128
file_type	0
auth_method	0
des_key	„0xa4b2c7d4e5f6a1ba1b2c3d41234“
key_number	0
card	
data	
0	
name	“datablock1_name”
position_start	1
position_end	15
test_value	“1234testme”
encoding	“ascii”
1	
name	“datablock2_name”
position_start	16
position_end	20
test_value	zero
encoding	“bcd”
2	
name	“datablock3_name”
position_start	21
position_end	30
test_value	17
encoding	“binary”