There are many image verification code forms on the network, those who do not generate the image of the verification code of the anti-cracking defense capability is simply vulnerable; someone directly in the source code to show the specific number, and then ask the visitor to enter a sum after the and, such as 3+5= how much, such a new code of verification, but unfortunately, Does not play a role in protection at all.
Flymorn improve the above new ideas, directly 3+6= how many forms of the use of ASP program to generate BMP picture format, and the number added and stored in the session, to increase the threshold of cracking; there is no graphic image to learn knowledge of the people can not be cracked. The code is as follows:
Copy Code code as follows:
<%
Response.Buffer = True
Response.ExpiresAbsolute = Now ()-1
Response.Expires = 0
Response.CacheControl = "No-cache"
Response.ContentType = "Image/bmp"
Call Com_creatvalidcode ()
Sub Com_creatvalidcode ()
Randomize
Dim I, II, III
Const Camount = 10 ' Number of values
Const ccode = "0123456789" ' Numerical range
Dim Vcolordata (2)
Vcolordata (0) = "" ' Black point to be converted to colored dots, temporarily undefined
Vcolordata (1) = ChrB (255) & ChrB (255) & ChrB (255) ' White dots
Dim Vcode (4), Vcodes ' produces a set of arbitrary numbers
For i = 0 to 3
Vcode (i) = Int (Rnd * camount) ' array equals total * random number
If I=1 then Vcode (i) = "11" ' second digit +
If I=3 then Vcode (i) = "10" ' fourth bit =
Vcodes=vcodes&mid (Ccode,vcode (i) +1,1) ' string equals string plus subsequent value
Next
Session ("Checkcode") =int (Mid (vcodes,1,1)) + Int (mid (vcodes,2,1)) ' Calculates the Add and value and assigns values to the session
Dim Vnumberdata (36)
Vnumberdata (0) =
"1110000111110111101111011110111101111011110111101111011110111101111011110111101111011110111110000111"
Vnumberdata (1) =
"1111011111110001111111110111111111011111111101111111110111111111011111111101111111110111111100000111"
Vnumberdata (2) =
"1110000111110111101111011110111111111011111111011111111011111111011111111011111111011110111100000011"
Vnumberdata (3) =
"1110000111110111101111011110111111110111111100111111111101111111111011110111101111011110111110000111"
Vnumberdata (4) =
"1111101111111110111111110011111110101111110110111111011011111100000011111110111111111011111111000011"
Vnumberdata (5) =
"1100000011110111111111011111111101000111110011101111111110111111111011110111101111011110111110000111"
Vnumberdata (6) =
"1111000111111011101111011111111101111111110100011111001110111101111011110111101111011110111110000111"
Vnumberdata (7) =
"1100000011110111011111011101111111101111111110111111110111111111011111111101111111110111111111011111"
Vnumberdata (8) =
"1110000111110111101111011110111101111011111000011111101101111101111011110111101111011110111110000111"
Vnumberdata (9) =
"1110001111110111011111011110111101111011110111001111100010111111111011111111101111011101111110001111"
' Expression =
Vnumberdata (10) =
"1111111111111111111111111111111000000001111111111111111111111000000001111111111111111111111111111111"
' means +
Vnumberdata (11) =
"1111111111111100111111110011111111001111100000000110000000011111001111111100111111110011111111111111"
Response.BinaryWrite ChrB & ChrB (a) & ChrB (230) & ChrB (4) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) &_
ChrB (0) & ChrB (0) & ChrB (a) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB () & ChrB (0) &_
ChrB (0) & ChrB (0) & ChrB (+) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (a) & ChrB (0) &_
ChrB (0) & ChrB (0) & ChrB (1) & ChrB (0)
Response.BinaryWrite ChrB & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (176) & ChrB (4) &_
ChrB (0) & ChrB (0) & ChrB (a) & ChrB (one) & ChrB (0) & ChrB (0) & ChrB (a) & ChrB (one) &_
ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) & ChrB (0) &_
ChrB (0) & ChrB (0)
For i = 9 to 0 Step-1 ' line
For II = 0 to 3 ' words
For III = 1 to 10 ' pixel points
If Mid (Vnumberdata (Vcode (ii)), I * + III, 1) = "0" then "produces colored dots, minus a fixed value to make the color darker
Dim a,b,c
A=abs (RND * 256-60)
B=abs (RND * 256-128)
C=abs (RND * 256-60)
Vcolordata (0) = ChrB (a) & ChrB (b) & ChrB (c)
Response.BinaryWrite Vcolordata (Mid vnumberdata (Vcode (ii)), I * + III, 1))
Else
Dim D,e,f ' produces a color background, a lighter color, or a random generation of noise to do the background.
D=abs (RND * 255)
E=abs (RND * 255)
F=abs (RND * 255)
If d+e+f>640 then ' can be modified to adjust background color depth
Vcolordata (1) = ChrB (d) & ChrB (E) & ChrB (f)
Response.BinaryWrite Vcolordata (Mid vnumberdata (Vcode (ii)), I * + III, 1))
Else
Response.BinaryWrite Vcolordata (Mid vnumberdata (Vcode (ii)), I * + III, 1))
End If
End If
Next
Next
Next
End Sub
%>
The above code can be directly saved as a file, such as vcode.asp, and then through the image of the way to call the change file, such as
Finally, it is the "5+6=" such as the form of random numbers added in BMP images, their and need you to calculate after filling in order to achieve the function of validation to prevent the machine from ravaging your site. If you are also concerned about the ASP image verification code, welcome message, let us exchange.
