The most important is sometimes to keep the message separate, but there is no such option, in the message of sumsung, sumsung should give the option of archive..
If Sumsung has kept the option like entering password before closing the phone in some of his phones, then I think Sumsung should give this option to all of their phones because it will strengthen the security of Sumsung's user and maybe Samsung team...
It seems that brother's girlfriend's call is coming to wish Happy Holi and brother is afraid that no one will know, so brother has kept his phone completely silent.