How to implement algorithm for trial version for 30 day by csharp ?

Question

I work on desktop application windows form by csharp language

I have issue I can't make it as trial for 30 day on customer pc

so How to do it trial version

I need to implement this logic algorithm but can't implement it

so How to do that please

suggest doing the following (during the first run of the application):

1. Create a registry entry to store an encrypted value of the expiration date (which can be calculated as n days from the installation date).

2. Create a hidden entry somewhere else (another place in the registry, a file stored in the Windows system folder, etc...) that indicates that step 1 was successfully completed. This is to allow the software to immediately stop functioning in case the user identifies and clears the registry entry created in 1.

3. Create another registry entry to store an encrypted value of the last date/time on which the software was run.

Now whenever the application is run (including the first time), you should:

1. Check for the registry entries 1, 2 and 3 above:

If 1 and 3 exist then

If they are correctly encrypted (unmodified) then

If the expiration date has not been reached AND the last-run date is older than the current date then

Run the application

Modify entry 3 to hold the current date (encrypted)

Else if the last-run data is newer than the current date then

Somebody has tried to change system clock. Catch! :-)

Else

The software has expired!

Else

Somebody tried to modify the encrypted values. Catch!

Else

If hidden entry 2 exists

Somebody cleared the entries 1 and 3. Catch!

Else

This is the first run! Create entries 1, 2 and 3

End if

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can you please help me implementing logic above please by coding here

if possible help me