The 4050 has 3 security levels : NONE, MEDIUM, and HIGH. To make a parameter medium secure, enter a $ sign before its name in the parameter dump, or in the params.txt file on the SD card.
To make a parameter high secure, enter $$ before its name in the parameter dump.
For example, to make the Decimal Point parameter secure, enter
00000002 $Decimal Point=1 [1]
Secure parameters can be changed via the front panel keyboard menus only if the user enters the configured security code. Note, however, that a high security code of 0 disables all security, whether the $ sign is present on a parameter or not.