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Posted 19 Jan 2002

, 19 Jan 2002
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## 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>
<title>Encrypt</title>

<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.

A list of licenses authors might use can be found here

## Share

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

## You may also be interested in...

 First PrevNext
 Overflow exception Member 304391912-Jul-16 7:00 Member 3043919 12-Jul-16 7:00
 Encrypt & Decrypt string [modified] c2love14-Nov-07 16:14 c2love 14-Nov-07 16:14
 Re: Encrypt & Decrypt string tommy skaue14-Nov-07 21:43 tommy skaue 14-Nov-07 21:43
 encrypt & decrypt password red-apple11-Aug-07 0:04 red-apple 11-Aug-07 0:04
 Re: encrypt & decrypt password tommy skaue11-Aug-07 2:56 tommy skaue 11-Aug-07 2:56
 Re: encrypt & decrypt password kenbhavin13-May-08 21:18 kenbhavin 13-May-08 21:18
 Re: encrypt & decrypt password kenbhavin13-May-08 21:16 kenbhavin 13-May-08 21:16
 one small change guildwyn24-Dec-06 11:17 guildwyn 24-Dec-06 11:17
 How to decrypt?? ShunHung14-Jul-05 17:11 ShunHung 14-Jul-05 17:11
 Re: How to decrypt?? Christian Graus14-Jul-05 17:47 Christian Graus 14-Jul-05 17:47
 modification of this code Anonymous2-Sep-04 14:24 Anonymous 2-Sep-04 14:24
 Re: modification of this code tommy skaue2-Sep-04 21:13 tommy skaue 2-Sep-04 21:13
 Re: modification of this code kryzchek18-May-05 7:40 kryzchek 18-May-05 7:40
 Re: modification of this code tommy skaue18-May-05 10:30 tommy skaue 18-May-05 10:30
 Same function ported to Perl soffen21-Nov-03 7:55 soffen 21-Nov-03 7:55
 Return value of Encrypt Function Ven Yetukuri3-Mar-03 8:54 Ven Yetukuri 3-Mar-03 8:54
 It wont work this way StarLite28-Jan-03 9:19 StarLite 28-Jan-03 9:19
 Re: It wont work this way tommy skaue28-Jan-03 21:14 tommy skaue 28-Jan-03 21:14
 Re: It wont work this way Anonymous29-Jan-03 3:34 Anonymous 29-Jan-03 3:34
 Re: It wont work this way tommy skaue29-Jan-03 20:59 tommy skaue 29-Jan-03 20:59
 I think it might be the special characters in the result... Its possible to change the function to span over only normal characters, but I dont use that function any longer. I havent deleted the article though. Its ok for reading how it can be done and to get your own ideas. There is MD5 for asp too... Lets see if its pastable: ```
<%
Private Const BITS_TO_A_BYTE=8
Private Const BYTES_TO_A_WORD=4
Private Const BITS_TO_A_WORD=32
Private m_lOnBits(30)
Private m_l2Power(30)
m_lOnBits(0)=CLng(1)
m_lOnBits(1)=CLng(3)
m_lOnBits(2)=CLng(7)
m_lOnBits(3)=CLng(15)
m_lOnBits(4)=CLng(31)
m_lOnBits(5)=CLng(63)
m_lOnBits(6)=CLng(127)
m_lOnBits(7)=CLng(255)
m_lOnBits(8)=CLng(511)
m_lOnBits(9)=CLng(1023)
m_lOnBits(10)=CLng(2047)
m_lOnBits(11)=CLng(4095)
m_lOnBits(12)=CLng(8191)
m_lOnBits(13)=CLng(16383)
m_lOnBits(14)=CLng(32767)
m_lOnBits(15)=CLng(65535)
m_lOnBits(16)=CLng(131071)
m_lOnBits(17)=CLng(262143)
m_lOnBits(18)=CLng(524287)
m_lOnBits(19)=CLng(1048575)
m_lOnBits(20)=CLng(2097151)
m_lOnBits(21)=CLng(4194303)
m_lOnBits(22)=CLng(8388607)
m_lOnBits(23)=CLng(16777215)
m_lOnBits(24)=CLng(33554431)
m_lOnBits(25)=CLng(67108863)
m_lOnBits(26)=CLng(134217727)
m_lOnBits(27)=CLng(268435455)
m_lOnBits(28)=CLng(536870911)
m_lOnBits(29)=CLng(1073741823)
m_lOnBits(30)=CLng(2147483647)

m_l2Power(0)=CLng(1)
m_l2Power(1)=CLng(2)
m_l2Power(2)=CLng(4)
m_l2Power(3)=CLng(8)
m_l2Power(4)=CLng(16)
m_l2Power(5)=CLng(32)
m_l2Power(6)=CLng(64)
m_l2Power(7)=CLng(128)
m_l2Power(8)=CLng(256)
m_l2Power(9)=CLng(512)
m_l2Power(10)=CLng(1024)
m_l2Power(11)=CLng(2048)
m_l2Power(12)=CLng(4096)
m_l2Power(13)=CLng(8192)
m_l2Power(14)=CLng(16384)
m_l2Power(15)=CLng(32768)
m_l2Power(16)=CLng(65536)
m_l2Power(17)=CLng(131072)
m_l2Power(18)=CLng(262144)
m_l2Power(19)=CLng(524288)
m_l2Power(20)=CLng(1048576)
m_l2Power(21)=CLng(2097152)
m_l2Power(22)=CLng(4194304)
m_l2Power(23)=CLng(8388608)
m_l2Power(24)=CLng(16777216)
m_l2Power(25)=CLng(33554432)
m_l2Power(26)=CLng(67108864)
m_l2Power(27)=CLng(134217728)
m_l2Power(28)=CLng(268435456)
m_l2Power(29)=CLng(536870912)
m_l2Power(30)=CLng(1073741824)

Private Function LShift(lValue,iShiftBits)
If iShiftBits=0 Then
LShift=lValue
Exit Function
ElseIf iShiftBits=31 Then
If lValue And 1 Then
LShift=&H80000000
Else
LShift=0
End If
Exit Function
ElseIf iShiftBits<0 Or iShiftBits>31 Then
Err.Raise 6
End If

If (lValue And m_l2Power(31-iShiftBits)) Then
LShift=((lValue And m_lOnBits(31-(iShiftBits+1)))*m_l2Power(iShiftBits)) Or &H80000000
Else
LShift=((lValue And m_lOnBits(31-iShiftBits))*m_l2Power(iShiftBits))
End If
End Function

Private Function RShift(lValue,iShiftBits)
If iShiftBits=0 Then
RShift=lValue
Exit Function
ElseIf iShiftBits=31 Then
If lValue And &H80000000 Then
RShift=1
Else
RShift=0
End If
Exit Function
ElseIf iShiftBits<0 Or iShiftBits>31 Then
Err.Raise 6
End If

RShift=(lValue And &H7FFFFFFE)\m_l2Power(iShiftBits)

If (lValue And &H80000000) Then
RShift=(RShift Or (&H40000000\m_l2Power(iShiftBits-1)))
End If
End Function

Private Function RotateLeft(lValue,iShiftBits)
RotateLeft=LShift(lValue,iShiftBits) Or RShift(lValue,(32-iShiftBits))
End Function

Dim lX4
Dim lY4
Dim lX8
Dim lY8
Dim lResult

lX8=lX And &H80000000
lY8=lY And &H80000000
lX4=lX And &H40000000
lY4=lY And &H40000000

lResult=(lX And &H3FFFFFFF)+(lY And &H3FFFFFFF)

If lX4 And lY4 Then
lResult=lResult Xor &H80000000 Xor lX8 Xor lY8
ElseIf lX4 Or lY4 Then
If lResult And &H40000000 Then
lResult=lResult Xor &HC0000000 Xor lX8 Xor lY8
Else
lResult=lResult Xor &H40000000 Xor lX8 Xor lY8
End If
Else
lResult=lResult Xor lX8 Xor lY8
End If

End Function

Private Function F(x,y,z)
F=(x And y) Or ((Not x) And z)
End Function

Private Function G(x,y,z)
G=(x And z) Or (y And (Not z))
End Function

Private Function H(x,y,z)
H=(x Xor y Xor z)
End Function

Private Function I(x,y,z)
I=(y Xor (x Or (Not z)))
End Function

Private Sub FF(a,b,c,d,x,s,ac)
a=RotateLeft(a,s)
End Sub

Private Sub GG(a,b,c,d,x,s,ac)
a=RotateLeft(a,s)
End Sub

Private Sub HH(a,b,c,d,x,s,ac)
a=RotateLeft(a,s)
End Sub

Private Sub II(a,b,c,d,x,s,ac)
a=RotateLeft(a,s)
End Sub

Private Function ConvertToWordArray(sMessage)
Dim lMessageLength
Dim lNumberOfWords
Dim lWordArray()
Dim lBytePosition
Dim lByteCount
Dim lWordCount

Const MODULUS_BITS=512
Const CONGRUENT_BITS=448

lMessageLength=Len(sMessage)

lNumberOfWords=(((lMessageLength+((MODULUS_BITS-CONGRUENT_BITS)\BITS_TO_A_BYTE))\(MODULUS_BITS\BITS_TO_A_BYTE))+1)*(MODULUS_BITS\BITS_TO_A_WORD)
ReDim lWordArray(lNumberOfWords-1)

lBytePosition=0
lByteCount=0
Do Until lByteCount >=lMessageLength
lWordCount=lByteCount\BYTES_TO_A_WORD
lBytePosition=(lByteCount Mod BYTES_TO_A_WORD)*BITS_TO_A_BYTE
lWordArray(lWordCount)=lWordArray(lWordCount) Or LShift(Asc(Mid(sMessage,lByteCount+1,1)),lBytePosition)
lByteCount=lByteCount+1
Loop

lWordCount=lByteCount\BYTES_TO_A_WORD
lBytePosition=(lByteCount Mod BYTES_TO_A_WORD)*BITS_TO_A_BYTE

lWordArray(lWordCount)=lWordArray(lWordCount) Or LShift(&H80,lBytePosition)

lWordArray(lNumberOfWords-2)=LShift(lMessageLength,3)
lWordArray(lNumberOfWords-1)=RShift(lMessageLength,29)

ConvertToWordArray=lWordArray
End Function

Private Function WordToHex(lValue)
Dim lByte
Dim lCount

For lCount=0 To 3
lByte=RShift(lValue,lCount*BITS_TO_A_BYTE) And m_lOnBits(BITS_TO_A_BYTE-1)
WordToHex=WordToHex & Right("0" & Hex(lByte),2)
Next
End Function

Public Function MD5(sMessage)
Dim x
Dim k
Dim AA
Dim BB
Dim CC
Dim DD
Dim a
Dim b
Dim c
Dim d

Const S11=7
Const S12=12
Const S13=17
Const S14=22
Const S21=5
Const S22=9
Const S23=14
Const S24=20
Const S31=4
Const S32=11
Const S33=16
Const S34=23
Const S41=6
Const S42=10
Const S43=15
Const S44=21

x=ConvertToWordArray(sMessage)

a=&H67452301
b=&HEFCDAB89
d=&H10325476

For k=0 To UBound(x) Step 16
AA=a
BB=b
CC=c
DD=d

FF a,b,c,d,x(k+0),S11,&HD76AA478
FF d,a,b,c,x(k+1),S12,&HE8C7B756
FF c,d,a,b,x(k+2),S13,&H242070DB
FF b,c,d,a,x(k+3),S14,&HC1BDCEEE
FF a,b,c,d,x(k+4),S11,&HF57C0FAF
FF d,a,b,c,x(k+5),S12,&H4787C62A
FF c,d,a,b,x(k+6),S13,&HA8304613
FF b,c,d,a,x(k+7),S14,&HFD469501
FF a,b,c,d,x(k+8),S11,&H698098D8
FF d,a,b,c,x(k+9),S12,&H8B44F7AF
FF c,d,a,b,x(k+10),S13,&HFFFF5BB1
FF b,c,d,a,x(k+11),S14,&H895CD7BE
FF a,b,c,d,x(k+12),S11,&H6B901122
FF d,a,b,c,x(k+13),S12,&HFD987193
FF c,d,a,b,x(k+14),S13,&HA679438E
FF b,c,d,a,x(k+15),S14,&H49B40821

GG a,b,c,d,x(k+1),S21,&HF61E2562
GG d,a,b,c,x(k+6),S22,&HC040B340
GG c,d,a,b,x(k+11),S23,&H265E5A51
GG b,c,d,a,x(k+0),S24,&HE9B6C7AA
GG a,b,c,d,x(k+5),S21,&HD62F105D
GG d,a,b,c,x(k+10),S22,&H2441453
GG c,d,a,b,x(k+15),S23,&HD8A1E681
GG b,c,d,a,x(k+4),S24,&HE7D3FBC8
GG a,b,c,d,x(k+9),S21,&H21E1CDE6
GG d,a,b,c,x(k+14),S22,&HC33707D6
GG c,d,a,b,x(k+3),S23,&HF4D50D87
GG b,c,d,a,x(k+8),S24,&H455A14ED
GG a,b,c,d,x(k+13),S21,&HA9E3E905
GG d,a,b,c,x(k+2),S22,&HFCEFA3F8
GG c,d,a,b,x(k+7),S23,&H676F02D9
GG b,c,d,a,x(k+12),S24,&H8D2A4C8A

HH a,b,c,d,x(k+5),S31,&HFFFA3942
HH d,a,b,c,x(k+8),S32,&H8771F681
HH c,d,a,b,x(k+11),S33,&H6D9D6122
HH b,c,d,a,x(k+14),S34,&HFDE5380C
HH a,b,c,d,x(k+1),S31,&HA4BEEA44
HH d,a,b,c,x(k+4),S32,&H4BDECFA9
HH c,d,a,b,x(k+7),S33,&HF6BB4B60
HH b,c,d,a,x(k+10),S34,&HBEBFBC70
HH a,b,c,d,x(k+13),S31,&H289B7EC6
HH d,a,b,c,x(k+0),S32,&HEAA127FA
HH c,d,a,b,x(k+3),S33,&HD4EF3085
HH b,c,d,a,x(k+6),S34,&H4881D05
HH a,b,c,d,x(k+9),S31,&HD9D4D039
HH d,a,b,c,x(k+12),S32,&HE6DB99E5
HH c,d,a,b,x(k+15),S33,&H1FA27CF8
HH b,c,d,a,x(k+2),S34,&HC4AC5665

II a,b,c,d,x(k+0),S41,&HF4292244
II d,a,b,c,x(k+7),S42,&H432AFF97
II c,d,a,b,x(k+14),S43,&HAB9423A7
II b,c,d,a,x(k+5),S44,&HFC93A039
II a,b,c,d,x(k+12),S41,&H655B59C3
II d,a,b,c,x(k+3),S42,&H8F0CCC92
II c,d,a,b,x(k+10),S43,&HFFEFF47D
II b,c,d,a,x(k+1),S44,&H85845DD1
II a,b,c,d,x(k+8),S41,&H6FA87E4F
II d,a,b,c,x(k+15),S42,&HFE2CE6E0
II c,d,a,b,x(k+6),S43,&HA3014314
II b,c,d,a,x(k+13),S44,&H4E0811A1
II a,b,c,d,x(k+4),S41,&HF7537E82
II d,a,b,c,x(k+11),S42,&HBD3AF235
II b,c,d,a,x(k+9),S44,&HEB86D391

Next

MD5=LCase(WordToHex(a) & WordToHex(b) & WordToHex(c) & WordToHex(d))
End Function
%>
``` ------------------------------------------ Hey! Stop reading my signature... stop it! hmm... you're still reading it...
 its a pretty good article Horatiu CRISTEA31-Jan-02 23:30 Horatiu CRISTEA 31-Jan-02 23:30
 Re: its a pretty good article tommy skaue1-Feb-02 0:18 tommy skaue 1-Feb-02 0:18
 Re: its a pretty good article Horatiu CRISTEA1-Feb-02 2:18 Horatiu CRISTEA 1-Feb-02 2:18
 Re: its a pretty good article tommy skaue1-Feb-02 2:18 tommy skaue 1-Feb-02 2:18
 Tommy's son (off-topic) Oz22-Jan-02 3:29 Oz 22-Jan-02 3:29
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