How to make a password verification system?

[glenjoy]

I am doing a security system and having a problem on coding techniques.

I am using a numeric keypad.

1. I will input the pin numbers on the keypad, but how to store them? Byte by byte so I have to create an array of variables and increment them each time?

2. How to compare them and the stored numeric password?

thanks.

 

[aryajur]

I don't see any problem in this, if you know the number of maximum people that will use the system you can allot the memory for it, with 1 place reserved for a pointer variable that points to the end of the current list. Whenever one enters the pin, just search the list for a match.

 

[samcheetah]

if you want to use a PIC you should check the PIC controlled intruder alarm that came in the April 2002 issue of EPE. that might give you an idea

 

[artem]

password checking routine assuming 6 character long password When you read keys call this function and check its return value .
0 means password match
1 continue key input
-1 password did not match
-2 input overflow

static char str[7];
static char pos =0;
static const char *psw_p = "WELL";

char CheckPassowrd(char key)
{
if (key == CHAR_ENTER)
{
str[pos] = 0;
pos = 0;
return (strcmp(psw_p, str)==0)? 0 : -1;
}
if (pos = 6)
{
pos = 0;
return -2;
}

str[pos++] = key;

return 1;
}

 

[issaiass]

To store data from keyboard, you need a keyboard buffer.
To handle verification, you need to compare the current buffer with actual password.

Go to http://www.geocities.com/issaiass/ and navigate to "Notas Tecnicas", intermediate section, and search for the LCD + KBD paper.