[exim] Security in Exim

Hello ,

i am having a problem in *exim4* ,that is* /etc/exim4/password.client*
file contain *email id* and *password* . The both email id and password in
Plain text format. so anyone can acess the password.client file can get my
password.
So please help me out how to hide or encrypt that password field in
*password.clien*t so no one can hack or know my password





thanks & regard
Ajit Mhatre