>> plainText = char((64:123))
plainText =
@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{
>> rot13(plainText)
ans =
@NOPQRSTUVWXYZABCDEFGHIJKLM[\]^_`nopqrstuvwxyzabcdefghijklm{