Simplify the following text for a Grade 7 native English-speaking person.
Original: The main factors in RC4 's success over such a wide range of applications are its speed and simplicity : efficient implementations in both software and hardware are very easy to develop .
Simplified: The two main reasons which helped its use over such a big range of applications are its speed and simplicity . Uses of RC4 in both software and hardware are extremely easy to develop .