Convert VB6 code to PHP - php

Question

I want to convert Visual Basic 6 Code to PHP Code. I am new to PHP please help me to convert my VB6 Code to PHP. So far I tried to convert this into php code when I tried the code there is an error in the "
CryptRC4 = CryptRC4 & Chr$((pvCryptXor(baS((CLng(baS(li)) + baS(lJ)) Mod 256), Asc(Mid$(sText, lIdx, 1)))));
part and also I don't know how to proceed to the sub functions. Please see the codes below. The vb code is used to encrypt strings. I want to convert it to php format.
PHP Code
<?php
function CryptRC4($sText,$sKey){
$baS = array(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,
32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,
64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,
80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,
96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,
112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,
128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255);
$baK = array(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,
32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,
64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,
80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,
96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,
112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,
128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,
144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,
176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,
208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255);
$bytSwap = 0;
$li = 0;
$lJ = 0;
$lIdx = 0;
for( $lIdx = 0; $lIdx < 256; $lIdx++){
$baS[$lIdx] = $lIdx;
$baK[$lIdx] = ord(substr($sKey, 1 + ($lIdx % strlen($sKey)), 1));
}
for($li = 0; $li < 256; $li++){
$lJ = ($baS[$li] + $baK[$li]) % 256;
$bytSwap = $baS[$li];
$baS[$li] = $baS[$lJ];
$baS[$lJ] = $bytSwap;
}
$li = 0;
$lJ = 0;
$data_str = "";
for($lIdx = 0; $lIdx < strlen($sText); $lIdx++){
$li = ($li + 1) % 256;
$lJ = ($lJ + $baS[$li]) % 256;
$bytSwap = $baS[$li];
$baS[$li] = $baS[$lJ];
$baS[$lJ] = $bytSwap;
#echo chr((pvCryptXor($baS[(round(($baS[$li]) + $baS[$lJ])) % 256], ord(substr($sText, $lIdx, 1)))));
$data_str .= chr((pvCryptXor($baS[(round(($baS[$li]) + $baS[$lJ])) % 256], ord(substr($sText, $lIdx, 1)))));
}
echo $data_str;
}
function pvCryptXor($li, $lJ){
if($li = $lJ){
$pcx = $lJ;
}
else {
$pcx = $li Xor $lJ;
}
return $pcx;
}
unction ToHexDump($sText) {
$lIdx;
for($lIdx = 1; $lIdx < strlen($sText); $lIdx++){
$thd .= Right$("0" & Hex(Asc(Mid(sText, lIdx, 1))), 2)
echo $thd;
}
return $thd;
}
FromHexDump("events");
function FromHexDump($sText) {
$fhd = "";
for($lIdx = 0; $lIdx < strlen($sText); $lIdx++){
$fhd .= chr(CLng("&H" & Mid(sText, lIdx, 2)));
}
return $fhd;
}
?>
VB Code:
Public Function CryptRC4(sText As String, sKey As String) As String
On Error Resume Next
Dim baS(0 To 255) As Byte
Dim baK(0 To 255) As Byte
Dim bytSwap As Byte
Dim li As Long
Dim lJ As Long
Dim lIdx As Long
For lIdx = 0 To 255
baS(lIdx) = lIdx
baK(lIdx) = Asc(Mid$(sKey, 1 + (lIdx Mod Len(sKey)), 1))
Next
For li = 0 To 255
lJ = (lJ + baS(li) + baK(li)) Mod 256
bytSwap = baS(li)
baS(li) = baS(lJ)
baS(lJ) = bytSwap
Next
li = 0
lJ = 0
For lIdx = 1 To Len(sText)
li = (li + 1) Mod 256
lJ = (lJ + baS(li)) Mod 256
bytSwap = baS(li)
baS(li) = baS(lJ)
baS(lJ) = bytSwap
CryptRC4 = CryptRC4 & Chr$((pvCryptXor(baS((CLng(baS(li)) + baS(lJ)) Mod 256), Asc(Mid$(sText, lIdx, 1)))))
Next
End Function
Private Function pvCryptXor(ByVal li As Long, ByVal lJ As Long) As Long
On Error Resume Next
If li = lJ Then
pvCryptXor = lJ
Else
pvCryptXor = li Xor lJ
End If
End Function
Public Function ToHexDump(sText As String) As String
On Error Resume Next
Dim lIdx As Long
For lIdx = 1 To Len(sText)
ToHexDump = ToHexDump & Right$("0" & Hex(Asc(Mid(sText, lIdx, 1))), 2)
Next
End Function
Public Function FromHexDump(sText As String) As String
On Error Resume Next
Dim lIdx As Long
For lIdx = 1 To Len(sText) Step 2
FromHexDump = FromHexDump & Chr$(CLng("&H" & Mid(sText, lIdx, 2)))
Next
End Function

Answer 1

I revised your updated code and it seems you only had a few minor errors in it, look and my changes:
I guess you can use the build in PHP function hex2bin and bin2hex instead fo you own hex conversion.
function CryptRC4($sText,$sKey){
$baS = range(0, 255); // you can use range instead of your manual arrays
$baK = range(0, 255);
$bytSwap = 0;
$li = 0;
$lJ = 0;
$lIdx = 0;
for( $lIdx = 0; $lIdx < 256; $lIdx++){
$baS[$lIdx] = $lIdx;
$baK[$lIdx] = ord(substr($sKey, 1 + ($lIdx % strlen($sKey)), 1));
}
for($li = 0; $li < 256; $li++){
$lJ = ($baS[$li] + $baK[$li]) % 256;
$bytSwap = $baS[$li];
$baS[$li] = $baS[$lJ];
$baS[$lJ] = $bytSwap;
}
$li = 0;
$lJ = 0;
$data_str = "";
for($lIdx = 0; $lIdx < strlen($sText); $lIdx++){
$li = ($li + 1) % 256;
$lJ = ($lJ + $baS[$li]) % 256;
$bytSwap = $baS[$li];
$baS[$li] = $baS[$lJ];
$baS[$lJ] = $bytSwap;
#echo chr((pvCryptXor($baS[(round(($baS[$li]) + $baS[$lJ])) % 256], ord(substr($sText, $lIdx, 1)))));
$data_str .= chr((pvCryptXor($baS[(round(($baS[$li]) + $baS[$lJ])) % 256], ord(substr($sText, $lIdx, 1)))));
}
return $data_str; // changed from echo to return
}
function pvCryptXor($li, $lJ){
if($li == $lJ){ // you had an error here, use == to compare instead of a single =
$pcx = $lJ;
}
else {
$pcx = $li ^ $lJ; // XOR function in PHP is the ^ operator
}
return $pcx;
}
$str_hex = bin2hex("events");
$str_enc = CryptRC4($str_hex,"password");
$str_dec = hex2bin(CryptRC4($str_enc,"password"));
echo $str_hex . PHP_EOL . $str_enc . PHP_EOL . $str_dec;
OUTPUT:
6576656e7473
'�����~i��
events
So it seems to me as it's actually encoding and decoding correctly!?

Answer 2

It seems the original VB6 implementation of CryptRC4 function is from my answer to "VB6 encrypt text using password" question on SO.
So let me try answering your Q with this short php implementation of all public functions in the VB6 snippet:
function CryptRC4($text, $key) {
return openssl_encrypt($text, "RC4-40", $key, 1 | 2);
}
function ToHexDump($text) {
return strtoupper(bin2hex($text));
}
function FromHexDump($text) {
return hex2bin($text);
}
You can excercise these one-liners with something like this:
$text = "a message here";
$password = "password";
$encr = ToHexDump(CryptRC4($text, $password));
$decr = CryptRC4(FromHexDump($encr), $password);
echo $text . PHP_EOL . $encr . PHP_EOL . $decr;

Answer 3

As it's intended for passwords, you can save yourself a lot of hassle. PHP has got built in functions (version 5.5 and newer) that are designed for dealing with the hashing of passwords and for verifying hashed passwords against the password submitted by a user. Have a read through the PHP relevant PHP manual pages http://php.net/manual/en/book.password.php