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Encrypting Passwords in ASP

, 19 Jan 2002
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A simple function to encrypt your users passwords
<!-- Add the rest of your HTML here -->

Introduction

Do you have a website where users need to login, and when they do you compare the password they enter with a column in a usertable? Some people do logins like this. It's easy to program and it works just fine. But what if someone got hold of the usertable and all the passwords of everyone? You may want to hide or encrypt the passwords in the usertable. Many programming languages have functions to do this. I make ASP-webpages, and I haven't found any quick functions to do this. There are plenty of components to do this, some free of charge even. But what if you cant install components on the webserver

Here is a short and neat way to encrypt your users passwords. You need two strings for it to work. Typically the username and the password.

Code

Function encrypt(x1, x2)
    s = ""
    t = 0
    For i = 1 to len(x1)
        t = t + asc(mid(x1,i,1))
    Next
    For i = 1 to len(x2)
        y = (t + asc(mid(x2,i,1)) * asc(mid(x2,((i+1) mod len(x2)+1),1))) mod 255
        s = s & chr(y)
    Next
    For i = (len(x2) + 1) to 10
        If t>598.8 Then t = 598.8
        y = t^3*i mod 255
        s = s & chr(y)
    Next
    encrypt = s
End Function

If you want to test this function you can create an asp-page and upload it to your website. Here's my codelisting to encrypt.asp

<%
Function encrypt(x1, x2)
    s = ""
    t = 0
    For i = 1 to len(x1)
        t = t + asc(mid(x1,i,1))
    Next
    For i = 1 to len(x2)
        y = (t + asc(mid(x2,i,1)) * asc(mid(x2,((i+1) mod len(x2)+1),1))) mod 255
        s = s & chr(y)
    Next
    For i = (len(x2) + 1) to 10
        If t>598.8 Then t = 598.8
        y = t^3*i mod 255
        s = s & chr(y)
    Next
    encrypt = s
End Function
%>

<html>
<head>
 <title>Encrypt</title>
</head>

<body>
<% If request.form("name") = "" Then %>
<form action="encrypt.asp" method="post">
<input type="text" name="name"><input type="text" name="pass">
<input type="submit">
</form>
<% Else  %>
<% response.write encrypt(request.form("name"),request.form("pass")) %>
<% End If %>
</body>
</html>

Remarks

  • The function is not reversible, so there is no way to take the result and reverse it into the password. You will need to recreate the password with a new one (some users seem to forget their passwords and always wants it retreieved)
  • This is not a high-level encryption, but its good enough to hide it from lame hackers (hehe).
  • The password is always sent from the user inputpage to the page encrypting it. Somewhere in between a hacker can fetch it. Secure zones (SSL) can remedy this.
  • Feel free to use the code to whatever you like. But if you alter it make a post in the thread related to this article so we all can share the fun.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

tommy skaue
Web Developer
Norway Norway
Tommy live in Tromsø, a city far up north in Norway. He does programming and webdevelopment for a living.

Comments and Discussions

 
QuestionEncrypt &amp; Decrypt string [modified] Pinmemberc2love14-Nov-07 17:14 
AnswerRe: Encrypt & Decrypt string Pinmembertommy skaue14-Nov-07 22:43 
Questionencrypt & decrypt password Pinmemberred-apple11-Aug-07 1:04 
AnswerRe: encrypt & decrypt password Pinmembertommy skaue11-Aug-07 3:56 
GeneralRe: encrypt & decrypt password Pinmemberkenbhavin13-May-08 22:18 
AnswerRe: encrypt & decrypt password Pinmemberkenbhavin13-May-08 22:16 
Generalone small change Pinmemberguildwyn24-Dec-06 12:17 
QuestionHow to decrypt?? PinsussShunHung14-Jul-05 18:11 
I can use this code,but I don't know how to decrypt...
AnswerRe: How to decrypt?? PinmemberChristian Graus14-Jul-05 18:47 
Generalmodification of this code PinsussAnonymous2-Sep-04 15:24 
GeneralRe: modification of this code Pinmembertommy skaue2-Sep-04 22:13 
GeneralRe: modification of this code Pinmemberkryzchek18-May-05 8:40 
GeneralRe: modification of this code Pinmembertommy skaue18-May-05 11:30 
GeneralSame function ported to Perl Pinmembersoffen21-Nov-03 8:55 
GeneralReturn value of Encrypt Function PinmemberVen Yetukuri3-Mar-03 9:54 
GeneralIt wont work this way PinsussStarLite28-Jan-03 10:19 
GeneralRe: It wont work this way Pinmembertommy skaue28-Jan-03 22:14 
GeneralRe: It wont work this way PinsussAnonymous29-Jan-03 4:34 
GeneralRe: It wont work this way Pinmembertommy skaue29-Jan-03 21:59 
Generalits a pretty good article PinmemberHoratiu CRISTEA1-Feb-02 0:30 
GeneralRe: its a pretty good article Pinmembertommy skaue1-Feb-02 1:18 
GeneralRe: its a pretty good article PinmemberHoratiu CRISTEA1-Feb-02 3:18 
GeneralRe: its a pretty good article Pinmembertommy skaue1-Feb-02 3:18 
GeneralTommy's son (off-topic) PinmemberOz22-Jan-02 4:29 
GeneralRe: Tommy's son (off-topic) Pinmembertommy skaue22-Jan-02 4:32 

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