Simplify the following text for a Grade 9 native English-speaking person.
Original: When trying to improve the security of a block cipher , one might get the idea to simply use two independent keys to encrypt the data twice and think that this would square the security of the double-encryption scheme .
Simplified: When trying to improve the security of a block cipher , one might get the idea to simply use two independent keys to encrypt the data twice . Naively , one might think that this would square the security of the double-encryption scheme .