Adding try and except documantation

[VictorRutskin]

issue is that there are many and do i even need it? examples for inputs that cause errors:

1. one char key for long string
2. not base64 key readable key

consider adding ways to check if base 64 or too short etc instead of throwing exceptions.

[VictorRutskin]

do i want to tell user why error happened? - incase of code cracking through .exe file etc