Converting a number to another number (encrypt - decrypt)

[brooksh]

I want to encrypt the ID number into another number. But then I want to be able to decrypt the encrypted number so that I can see the original number. Any simple ideas would be appreciated.

 

 

 

$original_num = "123-45";
$encrypted_num = encrypt($original_num);
echo $encrypted_num;
//$encrypted_num = somthing like 73632

 

$decrypted_num = decrypt($encrypted_num);
echo $decrypted_num;

 

 

 

[drummer101]

Give http://www.tonymarston.co.uk/php-mysql/encryption.htm a look.

 

It describes a reversible encryption routine for PHP. There is an online test

harness so you can see it working, and you have access to the code as

well.

 

[p2grace]

Here's a simple method:

 

$original = 123;
$secure = rand(100,999).base64_encode($original);
$unsecure = substr($secure,3);
$unsecure = base_64_decode($unsecure);
echo $unsecure; // will display 123

[drummer101]

wouldn't it just be:

echo $unsecure;

[brooksh]

Thanks, but is it possible to make $secure display only as a number?

[p2grace]

How secure do you need it to be?  You could create a simple algorithm to encrypt and decrypt it with.

[brooksh]

It doesn't need to be secure at all. I just don't want a basic user to figure out the real number.

[nikefido]

I'm not an encryption expert by any means but many encryptions are designed so you can't decrypt back to the original (which is why you see the encrypted passwords in databases)

 

example = "md5" or "sha"

 

 

I assume base_64 doesn't work this way, however, right?

[brooksh]

There are many encrypt and decrypt scripts out there. Some of them include a password so it is harder to decrypt. But I'm still looking for a script that will convert everything into a number. And yes base64 can be decrypted.

[p2grace]

base_64 can be decrypted.  If all you're looking for is a simple method of encrypting and it doesn't need to be secure you do something as simple as multiplying it by 17 and adding "32" to it.  then to decrypt subtract "32" and divide by 17. (Or whatever numbers you'd want to use)

 

Easy enough, but again not secure.

[brooksh]

This was my first thought, but each number has a "-" in it. I am just looking for some script out there that jumbles up the number.

[DyslexicDog]

So it's not a number then, it is a string.

[roopurt18]

<?php

// encrypt
$num = "123-45"; // starting number
$hyphen = !($tmp = strpos($num, '-')) ? 0 : $tmp; // locate the hyphen position
$num = str_replace('-', '', $num); // remove the hyphen
$num = $num * 4; // alter the number however you like
$num = (int)($hyphen . $num); // prefix the hyphen position to altered number and convert back to int
echo $num;

// decrypt
$hyphen = substr($num, 0, 1); // get hyphen position
$num = substr($num, 1); // trim hyphen position off the string
$num = $num / 4; // undo the number alteration
// put the hyphen back in the number
$num = substr($num, 0, $hyphen) . '-' . substr($num, $hyphen + 1);
echo $num;

?>

I might be off on the indexes in that second to last line, but that should give you an idea of a simple alteration you can make.  Feel fee to make it as complicated as you want.

[p2grace]

Give http://www.tonymarston.co.uk/php-mysql/encryption.htm a look.

 

It describes a reversible encryption routine for PHP. There is an online test

harness so you can see it working, and you have access to the code as

well.

 

 

This website appears to be down

[p2grace]

wouldn't it just be:

echo $unsecure;

 

yeah I was trying to show it would equal 123.  I edited it to show it in comments.