Questions & Answers about Kód lze rozluštit.
Lze means something like it is possible to or can be.
So Kód lze rozluštit literally works like:
The code — it is possible to decipher.
In natural English, that becomes The code can be deciphered.
A useful thing to remember is that lze is an impersonal form. It does not mean he/she can or I can. It is used for general possibility.
Because the pattern here is:
lze + infinitive
So Czech is saying it is possible to decipher the code, not using a normal finite verb like deciphers or will decipher.
This is a very common structure in more formal Czech:
So rozluštit stays in the infinitive because it is part of that construction.