.Net Coding Challenge #5

[BaussHacker]

Most peoples will just generate lables, which will make me laugh a bit, because you can easy crack them. They won't protect anything really.

[iCrack]

Most peoples will just generate lables, which will make me laugh a bit, because you can easy crack them. They won't protect anything really.

Which I actually did...
You probably right ...

[cOld fus1on]

I'm at work work right now

But when I get home, I'll do this..., prolly be in cSharp tho...

[KoBE]

My Submission (No Labels )+Comments (Click to View)

This could very easily be expanded on to make a decent Captcha verifier class. I whipped this up before bed so I didn't put any effort into a GUI. I mainly wanted to show a different way to do this rather then generating a Label.

Enjoy.

Code:

Imports System.Drawing
Imports System.Security.Cryptography
Public Class Form1
    Dim x As String     'used to store the text before painting, then stores the MD5 of what was painted
    Private Sub btnGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGenerate.Click
        'new bitmap to draw the captcha
        Dim xBitmap As New Bitmap(200, 50)
        'new brush to paint with
        Dim xBrush As New SolidBrush(Color.Black)
        'font used to draw captcha
        Dim xFont As New Font(FontFamily.GenericSansSerif, 20)
        'create a new graphic from the bitmat we created
        Dim gfx As Graphics = Graphics.FromImage(xBitmap)
        'return an 8 character string
        x = NewRand()
        'draw our string to the graphic
        gfx.DrawString(x, xFont, xBrush, 0, 0)
        'set the picture box image to our captcha
        pbCap.Image = xBitmap
        'md5 our captcha so incase stolen(via windows handle)
        x = TxtHash(x)
    End Sub
    Private Sub btnCheck_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCheck.Click
        'hash the answer and verify against the hashed captcha
        If TxtHash(txtAnswer.Text) = x Then
            MessageBox.Show("Sweet balls you got it!")
        Else
            MessageBox.Show("Uh oh, you suck.")
        End If
    End Sub

    Private Function NewRand()
        'characters allowed in the captcha
        Dim strText As String = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
        'new random number generator()
        Dim rand As New Random
        'holds our random character string
        Dim xString As String = ""
        For i As Integer = 0 To 8
            'loops 8 times, getting a random character from our allowed characters
            xString += strText.Substring(rand.Next(strText.Length - 1), 1)
        Next
        'return the result
        Return xString
    End Function
    Private Function TxtHash(ByVal str As String)
        'new md5 class
        Dim hash As MD5 = MD5.Create()
        'md5 hash in byte form
        Dim bytes As Byte() = hash.ComputeHash(System.Text.Encoding.ASCII.GetBytes(str))
        'return the md5 as a string
        Return BitConverter.ToString(bytes).Replace("-", "")
    End Function

End Class

[iCrack]

My Submission (No Labels )+Comments (Click to View)

This could very easily be expanded on to make a decent Captcha verifier class. I whipped this up before bed so I didn't put any effort into a GUI. I mainly wanted to show a different way to do this rather then generating a Label.

Enjoy.

Code:

Imports System.Drawing
Imports System.Security.Cryptography
Public Class Form1
    Dim x As String     'used to store the text before painting, then stores the MD5 of what was painted
    Private Sub btnGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGenerate.Click
        'new bitmap to draw the captcha
        Dim xBitmap As New Bitmap(200, 50)
        'new brush to paint with
        Dim xBrush As New SolidBrush(Color.Black)
        'font used to draw captcha
        Dim xFont As New Font(FontFamily.GenericSansSerif, 20)
        'create a new graphic from the bitmat we created
        Dim gfx As Graphics = Graphics.FromImage(xBitmap)
        'return an 8 character string
        x = NewRand()
        'draw our string to the graphic
        gfx.DrawString(x, xFont, xBrush, 0, 0)
        'set the picture box image to our captcha
        pbCap.Image = xBitmap
        'md5 our captcha so incase stolen(via windows handle)
        x = TxtHash(x)
    End Sub
    Private Sub btnCheck_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCheck.Click
        'hash the answer and verify against the hashed captcha
        If TxtHash(txtAnswer.Text) = x Then
            MessageBox.Show("Sweet balls you got it!")
        Else
            MessageBox.Show("Uh oh, you suck.")
        End If
    End Sub

    Private Function NewRand()
        'characters allowed in the captcha
        Dim strText As String = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"
        'new random number generator()
        Dim rand As New Random
        'holds our random character string
        Dim xString As String = ""
        For i As Integer = 0 To 8
            'loops 8 times, getting a random character from our allowed characters
            xString += strText.Substring(rand.Next(strText.Length - 1), 1)
        Next
        'return the result
        Return xString
    End Function
    Private Function TxtHash(ByVal str As String)
        'new md5 class
        Dim hash As MD5 = MD5.Create()
        'md5 hash in byte form
        Dim bytes As Byte() = hash.ComputeHash(System.Text.Encoding.ASCII.GetBytes(str))
        'return the md5 as a string
        Return BitConverter.ToString(bytes).Replace("-", "")
    End Function

End Class

Pretty nice man!
Well done!

[Modestep]

I made this in like 10 mins, i dont have mutch time

Spoiler (Click to View)

Code:

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cola As String = Random()
        Label1.Text = cola
    End Sub
    Public Function Random() As String
        Random = ""
        Const strUpper As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        Const strLower As String = "abcdefghijklmnopqrstuvwxyz"
        Const strNumbers As String = "1234567890"
        Dim strTotal As String
        Dim i As Short
        strTotal = strUpper & strLower & strNumbers
        For i = 1 To CInt("8")
            Random = Random & Mid(strTotal, Int((Rnd() * Len(strTotal)) + 1), 1)
        Next i
    End Function

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If TextBox1.Text = Label1.Text Then
            MessageBox.Show("You may crap stones now")
        Else
            Me.Close()
        End If
    End Sub
End Class

[iCrack]

I made this in like 10 mins, i dont have mutch time

Spoiler (Click to View)

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim cola As String = Random()
Label1.Text = cola
End Sub
Public Function Random() As String
Random = ""
Const strUpper As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Const strLower As String = "abcdefghijklmnopqrstuvwxyz"
Const strNumbers As String = "1234567890"
Dim strTotal As String
Dim i As Short
strTotal = strUpper & strLower & strNumbers
For i = 1 To CInt("8")
Random = Random & Mid(strTotal, Int((Rnd() * Len(strTotal)) + 1), 1)
Next i
End Function

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
If TextBox1.Text = Label1.Text Then
MessageBox.Show("You may crap stones now")
Else
Me.Close()
End If
End Sub
End Class

http://i.min.us/in25DI.PNG

I think you may work a bit in the GUI ...
Use Code and Image tags instead tho...

[ﾓrainee]

It looks great mate!

Vwry nice .I like it

[thanasis2028]

Ok here is my submission:

Spoiler (Click to View)

I used the RichTextBox and made some rtf encoding to achieve this

Code:

Public Class Form1
    Private r As New Random()
    Private Function GetRandomRTF(ByVal Length As Byte) As String
        Dim Chars As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
        Dim Str As String = ""
        Dim FinalStr As String = ""
        For i As Byte = 1 To Length
            Str = Chars.Chars(r.Next(Chars.Length - 1))

            Select Case r.Next(5) 'Colors
                Case 0
                    Str = "\cf1 " + Str
                Case 1
                    Str = "\cf2 " + Str
                Case 2
                    Str = "\cf3 " + Str
                Case 3
                    Str = "\cf4 " + Str
                Case 4
                    Str = "\cf5 " + Str
            End Select

            Select Case r.Next(7) 'Bold/Italic/Underline
                Case 0
                    Str = "{\b " + Str + "}"
                Case 1
                    Str = "{\i " + Str + "}"
                Case 2
                    Str = "{\ul " + Str + "}"
                Case 3
                    Str = "{\b {\i " + Str + "}}"
                Case 4
                    Str = "{\b {\ul " + Str + "}}"
                Case 5
                    Str = "{\i {\ul " + Str + "}}"
            End Select

            FinalStr += Str
        Next
        Return FinalStr
    End Function

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.BackColor = Color.FromArgb(103, 153, 52)
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        RichTextBox1.Clear()
        TextBox1.Clear()
        RichTextBox1.Text = "initialtext"
        RichTextBox1.Rtf = Replace(RichTextBox1.Rtf, "initialtext", "{\colortbl;\red0\green0\blue0;\red255\green0\blue0;\red0\green255\blue0;\red0\green0\blue255;\red255\green0\blue255;}" + GetRandomRTF(r.Next(6, 11)))
        Button2.Enabled = True
        TextBox1.Select()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If TextBox1.Text = RichTextBox1.Text Then
            MsgBox("You got it right! You are not a machine!", , "Access Granted!")
        Else
            MsgBox("Machines get no access to the system!", , "Access Denied!")
        End If
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.Close()
    End Sub

    Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
        If e.KeyCode = Keys.Enter Then Button2_Click(Me, EventArgs.Empty)
    End Sub
End Class

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