Username & Password comparison!

[cashflowtips]

i having a problem on how to check the user name and password during registration session...

 

the input like this :-

 

user name : admin

password : admin123

/* False */

 

if something like this happen, the system should output error message because the password have partial words same as the user name. if can, i would like to limit it to allow only 3 consecutive letter to be same.

 

example :-

 

user name : admin

password : admi123

/* False */

 

user name : admin

password : adm789

/* True (allowed) */

 

can anybody help me here?

[redarrow]

<?php

$username="admin";

$password="admin123";

$cheek1=substr($username,0,3);

$cheek2=substr($password,0,3);

if($cheek1==$cheek2){

echo "Sorry the username and password have the same first three letters";

}else{

echo "Username and password are valid as the first three letters dont match";

}

?>

[cashflowtips]

<?php

$username="admin";

$password="admin123";

$cheek1=substr($username,0,3);

$cheek2=substr($password,0,3);

if($cheek1==$cheek2){

echo "Sorry the username and password have the same first three letters";

}else{

echo "Username and password are valid as the first three letters dont match";

}

?>

 

thank you for you reply... really appreciate it... i have another question. can it trace something like this :-

 

user name : 12admin99

password : !(admin)!

 

will it return true or false?

[kireol]

the above is nice.  here's an alternative which would also catch a password of "theadmin" or "1admin"

 

<?php

$username="admin";

$password="admin123";

$cheek=substr($admin,0,3);

if(strstr($password,$cheek)
{
echo "Sorry the username and password have the same first three letters";
}else{

echo "Username and password are valid as the first three letters dont match";

}

?>

[d.shankar]

You can make use of this functions to find the similarities between the username and password in percentiles..

If the similarity rate is high , then you can fail this attempt ..else success.

 

similar_text

http://www.php.net/manual/en/function.similar-text.php

 

Levenshtein

http://www.php.net/manual/en/function.levenshtein.php

 

You can find similar_text more flexible.

[jitesh]

<?php

$username = "admin";
$password = "admin123";

if(preg_match("/".$username."/i",$password)){
echo "Please Change Password";
}else{
echo "Password is ok";
}

?>

[cashflowtips]

<?php

$username = "admin";
$password = "admin123";

if(preg_match("/".$username."/i",$password)){
echo "Please Change Password";
}else{
echo "Password is ok";
}

?>

 

but how can i limit it like i mentioned above?

[jitesh]

<?php

$username = "admin";
$password = "admin123";

$sub_username = substr($username,0,4);

if(preg_match("/".$sub_username."/i",$password)){
echo "Please Change Password";
}else{
echo "Password is ok";
}

?>