im back!!! from holiday 
now so many people asking for phone security ...
yup theres a way, but u must modd ur phone.....
SE k810i have patch that allow u to lock ur msg files and others..
but its not easy as installing software... there got some risk to do it..
are u interested in doing it??

ok but this is on ur own risk...

1stly u must read the basic info ... click here
make sure u understand it...

then download the important tools to mod...
XS++

SEtool2lite v1.11

USB driver

then find ur phone firmware and download it... (click here)
after that u can start mod ur phone by applying quick access patch.. this is to break ur phone
security to enable patching on ur phone.... but this only work for CID52...
make sure ur phone is CID52.. others than CID52 cant do this method.. u can refer to the tutorial...

tutorial quick access patch

after done the quick access patch now u can patch ur phone.... here the tutorial... tutorial applying patches

u can got more patch on this site... k810i moding thread

find the privacy patch to enable security lock system....

hope u understand with the explanation....
gud luck..

juz right click at SEK810i banner propeties and u can get the image link....
if you make mistake on modding, mayb ur phone will be dead...