Dear John,
Thanks for you suggestion, but I 'm not 100% understand. So, I would like to suggest me some sample codes which use sys(0).
Thanks again for your time.

>An alternative approach would be to use the SYS(0) function to screen the current user versus the user table. SYS(0) returns machine and user name...this would mean that you're letting network security to work for you and you don't have to store passwords as the network O/S is dealing with that.
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>>Suppose I have created program from VFP. I would like my users
>>input their passwords in my program 's table. My objective is :
>>I don't want others people who know VFP to see my passwords ' table
>>from opening VFP program. I want password table can open or see only in my program.
>> If you can suggest me please help me with your sample code.
>> Thanks again for your time.