一个很简单的验证码程序

原程序
http://vifo.vicp.net:8088/datalib/showtopic.asp?id=108:10:1:1

主程序共三个

我的调用方式 <script language="javascript" src="/verify/num.asp"></script>
验证方式 if trim(loginnum)<>trim(session("loginnum")) then
response.write error("验证码错误！")
response.end
end if

num.asp

<%
### to encrypt/decrypt include this code in your page
### strmyencryptedstring = encryptstring(strstring)
### strmydecryptedstring = decryptstring(strmyencryptedstring)
### you are free to use this code as long as credits remain in place
### also if you improve this code let me know.

private function encryptstring(strstring)
####################################################################
### crypt function ? 2001 by slavic kozyuk grindkore@yahoo.com ###
### arguments: strstring <— string you wish to encrypt ###
### output: encrypted hex string ###
####################################################################

dim charhexset, intstringlen, strtemp, strraw, i, intkey, intoffset
randomize timer

intkey = round((rnd * 1000000) + 1000000) ##### key bitsize
intoffset = round((rnd * 1000000) + 1000000) ##### keyoffset bitsize

if isnull(strstring) = false then
strraw = strstring
intstringlen = len(strraw)

for i = 0 to intstringlen – 1
strtemp = left(strraw, 1)
strraw = right(strraw, len(strraw) – 1)
charhexset = charhexset & hex(asc(strtemp) * intkey)& hex(intkey)
next

encryptstring = charhexset & "|" & hex(intoffset + intkey) & "|" & hex(intoffset)
else
encryptstring = ""
end if
end function

private function decryptstring(strcryptstring)
####################################################################
### crypt function ? 2001 by slavic kozyuk grindkore@yahoo.com ###
### arguments: encrypted hex stringt ###
### output: decrypted ascii string ###
####################################################################
### note this function uses hexconv() and get_hxno() functions ###
### so make sure they are not removed ###
####################################################################

dim strraw, arhexcharset, i, intkey, intoffset, strrawkey, strhexcrypdata

strrawkey = right(strcryptstring, len(strcryptstring) – instr(strcryptstring, "|"))
intoffset = right(strrawkey, len(strrawkey) – instr(strrawkey,"|"))
intkey = hexconv(left(strrawkey, instr(strrawkey, "|") – 1)) – hexconv(intoffset)
strhexcrypdata = left(strcryptstring, len(strcryptstring) – (len(strrawkey) + 1))

arhexcharset = split(strhexcrypdata, hex(intkey))

for i=0 to ubound(arhexcharset)
strraw = strraw & chr(hexconv(arhexcharset(i))/intkey)
next

decryptstring = strraw
end function

private function hexconv(hexvar)
dim hxx, hxx_var, multiply
if hexvar <> "" then
hexvar = ucase(hexvar)
hexvar = strreverse(hexvar)
dim hx()
redim hx(len(hexvar))
hxx = 0
hxx_var = 0
for hxx = 1 to len(hexvar)
if multiply = "" then multiply = 1
hx(hxx) = mid(hexvar,hxx,1)
hxx_var = (get_hxno(hx(hxx)) * multiply) + hxx_var
multiply = (multiply * 16)
next
hexvar = hxx_var
hexconv = hexvar
end if
end function

private function get_hxno(ghx)
if ghx = "a" then
ghx = 10
elseif ghx = "b" then
ghx = 11
elseif ghx = "c" then
ghx = 12
elseif ghx = "d" then
ghx = 13
elseif ghx = "e" then
ghx = 14
elseif ghx = "f" then
ghx = 15
end if
get_hxno = ghx
end function

randomize
num = int(7999*rnd+2000) 计数器的值
num2 = encryptstring(num)
session("loginnum")=num
%>
document.write("<img src=/verify/count.asp?sksid=<%=num2%>>") 这里是调用图片的路径

count.asp

<!–#include file="numimg.asp"–>

<%
### to encrypt/decrypt include this code in your page
### strmyencryptedstring = encryptstring(strstring)
### strmydecryptedstring = decryptstring(strmyencryptedstring)
### you are free to use this code as long as credits remain in place
### also if you improve this code let me know.

private function encryptstring(strstring)
####################################################################
### crypt function ? 2001 by slavic kozyuk grindkore@yahoo.com ###
### arguments: strstring <— string you wish to encrypt ###
### output: encrypted hex string ###
####################################################################

dim charhexset, intstringlen, strtemp, strraw, i, intkey, intoffset
randomize timer

intkey = round((rnd * 1000000) + 1000000) ##### key bitsize
intoffset = round((rnd * 1000000) + 1000000) ##### keyoffset bitsize

if isnull(strstring) = false then
strraw = strstring
intstringlen = len(strraw)

for i = 0 to intstringlen – 1
strtemp = left(strraw, 1)
strraw = right(strraw, len(strraw) – 1)
charhexset = charhexset & hex(asc(strtemp) * intkey)& hex(intkey)
next

encryptstring = charhexset & "|" & hex(intoffset + intkey) & "|" & hex(intoffset)
else
encryptstring = ""
end if
end function

private function decryptstring(strcryptstring)
####################################################################
### crypt function ? 2001 by slavic kozyuk grindkore@yahoo.com ###
### arguments: encrypted hex stringt ###
### output: decrypted ascii string ###
####################################################################
### note this function uses hexconv() and get_hxno() functions ###
### so make sure they are not removed ###
####################################################################

dim strraw, arhexcharset, i, intkey, intoffset, strrawkey, strhexcrypdata

strrawkey = right(strcryptstring, len(strcryptstring) – instr(strcryptstring, "|"))
intoffset = right(strrawkey, len(strrawkey) – instr(strrawkey,"|"))
intkey = hexconv(left(strrawkey, instr(strrawkey, "|") – 1)) – hexconv(intoffset)
strhexcrypdata = left(strcryptstring, len(strcryptstring) – (len(strrawkey) + 1))

arhexcharset = split(strhexcrypdata, hex(intkey))

for i=0 to ubound(arhexcharset)
strraw = strraw & chr(hexconv(arhexcharset(i))/intkey)
next

decryptstring = strraw
end function

private function hexconv(hexvar)
dim hxx, hxx_var, multiply
if hexvar <> "" then
hexvar = ucase(hexvar)
hexvar = strreverse(hexvar)
dim hx()
redim hx(len(hexvar))
hxx = 0
hxx_var = 0
for hxx = 1 to len(hexvar)
if multiply = "" then multiply = 1
hx(hxx) = mid(hexvar,hxx,1)
hxx_var = (get_hxno(hx(hxx)) * multiply) + hxx_var
multiply = (multiply * 16)
next
hexvar = hxx_var
hexconv = hexvar
end if
end function

private function get_hxno(ghx)
if ghx = "a" then
ghx = 10
elseif ghx = "b" then
ghx = 11
elseif ghx = "c" then
ghx = 12
elseif ghx = "d" then
ghx = 13
elseif ghx = "e" then
ghx = 14
elseif ghx = "f" then
ghx = 15
end if
get_hxno = ghx
end function

%>

<%
dim image
dim width, height
dim num
dim digtal
dim length
dim sort
length = 4 自定计数器长度

redim sort( length )

num=cint(decryptstring(request.querystring("sksid")))
digital = ""
for i = 1 to length -len( num ) 补0
digital = digital & "0"
next
for i = 1 to len( num )
digital = digital & mid( num, i, 1 )
next
for i = 1 to len( digital )
sort(i) = mid( digital, i, 1 )
next
width = 8 * len( digital ) 图像的宽度
height = 10 图像的高度，在本例中为固定值

response.contenttype="image/x-xbitmap"

hc=chr(13) & chr(10)

image = "#define counter_width " & width & hc
image = image & "#define counter_height " & height & hc
image = image & "static unsigned char counter_bits[]={" & hc

for i = 1 to height
for j = 1 to length
image = image & a(sort(j),i) & ","
next
next

image = left( image, len( image ) – 1 ) 去掉最后一个逗号
image = image & "};" & hc
%>
<%
response.write image

%>

numimg.asp

<%
dim a(10,10)

a(0,1) = "0x3c" 数字0
a(0,2) = "0x66"
a(0,3) = "0xc3"
a(0,4) = "0xc3"
a(0,5) = "0xc3"
a(0,6) = "0xc3"
a(0,7) = "0xc3"
a(0,8) = "0xc3"
a(0,9) = "0x66"
a(0,10)= "0x3c"

a(1,1) = "0x18" 数字1
a(1,2) = "0x1c"
a(1,3) = "0x18"
a(1,4) = "0x18"
a(1,5) = "0x18"
a(1,6) = "0x18"
a(1,7) = "0x18"
a(1,8) = "0x18"
a(1,9) = "0x18"
a(0,10)= "0x7e"

a(2,1) = "0x3c" 数字2
a(2,2) = "0x66"
a(2,3) = "0x60"
a(2,4) = "0x60"
a(2,5) = "0x30"
a(2,6) = "0x18"
a(2,7) = "0x0c"
a(2,8) = "0x06"
a(2,9) = "0x06"
a(2,10)= "0x7e"

a(3,1) = "0x3c" 数字3
a(3,2) = "0x66"
a(3,3) = "0xc0"
a(3,4) = "0x60"
a(3,5) = "0x1c"
a(3,6) = "0x60"
a(3,7) = "0xc0"
a(3,8) = "0xc0"
a(3,9) = "0x66"
a(3,10)= "0x38"

a(4,1) = "0x38" 数字4
a(4,2) = "0x3c"
a(4,3) = "0x36"
a(4,4) = "0x33"
a(4,5) = "0x33"
a(4,6) = "0x33"
a(4,7) = "0xff"
a(4,8) = "0x30"
a(4,9) = "0x30"
a(4,10)= "0xfe"

a(5,1) = "0xfe" 数字5
a(5,2) = "0xfe"
a(5,3) = "0x06"
a(5,4) = "0x06"
a(5,5) = "0x3e"
a(5,6) = "0x60"
a(5,7) = "0xc0"
a(5,8) = "0xc3"
a(5,9) = "0x66"
a(5,10)= "0x3c"

a(6,1) = "0x60" 数字6
a(6,2) = "0x30"
a(6,3) = "0x18"
a(6,4) = "0x0c"
a(6,5) = "0x3e"
a(6,6) = "0x63"
a(6,7) = "0xc3"
a(6,8) = "0xc3"
a(6,9) = "0x66"
a(6,10) ="0x3c"

a(7,1) = "0xff" 数字7
a(7,2) = "0xc0"
a(7,3) = "0x60"
a(7,4) = "0x30"
a(7,5) = "0x18"
a(7,6) = "0x18"
a(7,7) = "0x18"
a(7,8) = "0x18"
a(7,9) = "0x18"
a(7,10)= "0x18"

a(8,1) = "0x3c" 数字8
a(8,2) = "0x66"
a(8,3) = "0xc3"
a(8,4) = "0x66"
a(8,5) = "0x3c"
a(8,6) = "0x66"
a(8,7) = "0xc3"
a(8,8) = "0xc3"
a(8,9) = "0x66"
a(8,10)= "0x3c"

a(9,1) = "0x3c" 数字9
a(9,2) = "0x66"
a(9,3) = "0xc3"
a(9,4) = "0xc3"
a(9,5) = "0x66"
a(9,6) = "0x3c"
a(9,7) = "0x18"
a(9,8) = "0x0c"
a(9,9) = "0x06"
a(9,10)= "0x03"

%>