How can it be possible to isolate the email and notes apps from malicious script installed in the smart phones?

Question

working on a project need help on this issue.

Answer 1

encrypting and decrypting, it's pretty simple to make in java

pseudocode:
loop through every char in your email string
change the char by adding, multiplying, subtracting etc by any value
save the output.

read the output
loop through every char again
do the same backwards
(so if you first done *3 -2 do +2 /3)
you got your output