.Net Coding Challenge #5

[iCrack]

Challenge: Captcha Verification
End date: 1st June, 2011
Details: Add a Captcha Verification to your program. It doesn't matter how advanced it is. What matters is if you can accomplish this successfully.

Requirements: There are no requirements for this. You just need to make it work...

How to enter:
Enter by responding to this thread stating are going to attempt this challenge. Do not PM me.

How to submit:
Submit by using a spoiler tag to hide you submission. Include a screen shot, the source code in {code} tags, a download link to the project. (Optional but preferred)

Choosing a winner:
If you complete this.. then you are a winner. This is not a contest to see who 'coded the best'. This is a challenge to see if you can complete it. Visual is Optional, but it will make your program look nice to the SF community.

Disclaimer:
This is meant to be fun and constructive. By submitting your code for this challenge you agree not to get butt-hurt if somebody criticizes your work. Take the criticism, learn from it, and move on. Also, all comments made should be constructive. NO FLAMING ALLOWED. All flaming attempts will be reported.

To everyone: Good luck.

Submissions: The High Roller; iCrack; KoBE; dudesons123; thanasis2028...

[Resistance]

Heres my submission:

Spoiler (Click to View)

Of course I could have made it have some letters and use alphanumeric values but I decide no further.

Download Link:
Download Link
Screney:

[iCrack]

Heres my submission:

Spoiler (Click to View)

Of course I could have made it have some letters and use alphanumeric values but I decide no further.

Download Link:
Download Link
Screney:

It looks great mate! I made one as well (should I post it? 'cause this is my challenge )

[Resistance]

It looks great mate! I made one as well (should I post it? 'cause this is my challenge )

Yes that is the tradition. Sure why not post.

[iCrack]

Here's my submission then...

Spoiler (Click to View)

Module1 - Generate Captcha

Code:

Imports System
Imports System.Security.Cryptography
Module Module1
    Public Class RandomCAPTCHA
        Private Shared DEFAULT_MIN_CAPTCHA_LENGTH As Integer = 1
        Private Shared DEFAULT_MAX_CAPTCHA_LENGTH As Integer = 1
        Private Shared CAPTCHA_CHARS_UCASE As String = "ABCDEFGHJKLMNPQRSTWXYZ"
        Private Shared CAPTCHA_CHARS_LCASE As String = "abcdefgijkmnopqrstwxyz"
        Private Shared CAPTCHA_CHARS_NUMERIC As String = "123456789"
        Private Shared CAPTCHA_CHARS_SPECIAL As String = "*$-+?_&=!%{}/"
        Public Shared Function Generate() As String
            Generate = Generate(DEFAULT_MIN_CAPTCHA_LENGTH, DEFAULT_MAX_CAPTCHA_LENGTH)
        End Function
        Public Shared Function Generate(ByVal length As Integer) As String
            Generate = Generate(length, length)
        End Function
        Public Shared Function Generate(ByVal minLength As Integer, ByVal maxLength As Integer) As String
            If (minLength <= 0 Or maxLength <= 0 Or minLength > maxLength) Then
                Generate = Nothing
            End If
            Dim charGroups As Char()() = New Char()() {CAPTCHA_CHARS_LCASE.ToCharArray(), CAPTCHA_CHARS_UCASE.ToCharArray(), CAPTCHA_CHARS_NUMERIC.ToCharArray(), CAPTCHA_CHARS_SPECIAL.ToCharArray()}
            Dim charsLeftInGroup As Integer() = New Integer(charGroups.Length - 1) {}
            Dim I As Integer
            For I = 0 To charsLeftInGroup.Length - 1
                charsLeftInGroup(I) = charGroups(I).Length
            Next
            Dim leftGroupsOrder As Integer() = New Integer(charGroups.Length - 1) {}
            For I = 0 To leftGroupsOrder.Length - 1
                leftGroupsOrder(I) = I
            Next
            Dim randomBytes As Byte() = New Byte(3) {}
            Dim rng As RNGCryptoServiceProvider = New RNGCryptoServiceProvider()
            rng.GetBytes(randomBytes)
            Dim seed As Integer = ((randomBytes(0) And &H7F) << 24 Or randomBytes(1) << 16 Or randomBytes(2) << 8 Or randomBytes(3))
            Dim random As Random = New Random(seed)
            Dim CAPTCHA As Char() = Nothing
            If (minLength < maxLength) Then
                CAPTCHA = New Char(random.Next(minLength - 1, maxLength)) {}
            Else
                CAPTCHA = New Char(minLength - 1) {}
            End If
            Dim nextCharIdx As Integer
            Dim nextGroupIdx As Integer
            Dim nextLeftGroupsOrderIdx As Integer
            Dim lastCharIdx As Integer
            Dim lastLeftGroupsOrderIdx As Integer = leftGroupsOrder.Length - 1
            For I = 0 To CAPTCHA.Length - 1
                If (lastLeftGroupsOrderIdx = 0) Then
                    nextLeftGroupsOrderIdx = 0
                Else
                    nextLeftGroupsOrderIdx = random.Next(0, lastLeftGroupsOrderIdx)
                End If
                nextGroupIdx = leftGroupsOrder(nextLeftGroupsOrderIdx)
                lastCharIdx = charsLeftInGroup(nextGroupIdx) - 1
                If (lastCharIdx = 0) Then
                    nextCharIdx = 0
                Else
                    nextCharIdx = random.Next(0, lastCharIdx + 1)
                End If
                CAPTCHA(I) = charGroups(nextGroupIdx)(nextCharIdx)
                If (lastCharIdx = 0) Then
                    charsLeftInGroup(nextGroupIdx) = _
                                    charGroups(nextGroupIdx).Length
                Else
                    If (lastCharIdx <> nextCharIdx) Then
                        Dim temp As Char = charGroups(nextGroupIdx)(lastCharIdx)
                        charGroups(nextGroupIdx)(lastCharIdx) = _
                                    charGroups(nextGroupIdx)(nextCharIdx)
                        charGroups(nextGroupIdx)(nextCharIdx) = temp
                    End If
                    charsLeftInGroup(nextGroupIdx) = _
                               charsLeftInGroup(nextGroupIdx) - 1
                End If
                If (lastLeftGroupsOrderIdx = 0) Then
                    lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1
                Else
                    If (lastLeftGroupsOrderIdx <> nextLeftGroupsOrderIdx) Then
                        Dim temp As Integer = _
                                    leftGroupsOrder(lastLeftGroupsOrderIdx)
                        leftGroupsOrder(lastLeftGroupsOrderIdx) = _
                                    leftGroupsOrder(nextLeftGroupsOrderIdx)
                        leftGroupsOrder(nextLeftGroupsOrderIdx) = temp
                    End If
                    lastLeftGroupsOrderIdx = lastLeftGroupsOrderIdx - 1
                End If
            Next
            Generate = New String(CAPTCHA)
        End Function
    End Class
    Sub Main()
        Dim I As Integer
        For I = 1 To 1
            Form1.Label1.Text = RandomCAPTCHA.Generate(1)
            Form1.Label2.Text = RandomCAPTCHA.Generate(1)
            Form1.Label3.Text = RandomCAPTCHA.Generate(1)
            Form1.Label4.Text = RandomCAPTCHA.Generate(1)
            Form1.Label5.Text = RandomCAPTCHA.Generate(1)
            Form1.Label6.Text = RandomCAPTCHA.Generate(1)
        Next
    End Sub
End Module

Form1 - Captcha Verification

Code:

Public Class Form1
    Private Sub Generate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Generate.Click
        Call Main()
        Verification.Clear()
    End Sub
    Private Sub Test_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Test.Click
        Dim aa = Label1.Text
        Dim bb = Label2.Text
        Dim cc = Label3.Text
        Dim dd = Label4.Text
        Dim ee = Label5.Text
        Dim ff = Label6.Text
        If Verification.Text = aa + bb + cc + dd + ee + ff Then
            MsgBox("You did it!")
        Else
            MsgBox("Nop!")
        End If
    End Sub
End Class

Download .EXE: http://localhostr.com/file/6O0KRds/Captcha.exe

[Modestep]

I will give this a try, its fun. But i first need to finish a website for school

[iCrack]

I will give this a try, its fun. But i first need to finish a website for school

Ok Sir! Be sure to come back here!

[KoBE]

Now that my finals are done I should have some spare time to make this. I'll post a submission soon.

[milopeach]

Wow these are amazing, i might even use this for a program in the near future. I was also going to compete but decided not to because the competition is too great.

[iCrack]

Now that my finals are done I should have some spare time to make this. I'll post a submission soon.

Yeah! I was wondering why you weren't posting here!
Good Luck!

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Wow these are amazing, i might even use this for a program in the near future. I was also going to compete but decided not to because the competition is too great.

If you use any of the sources of the people who participated give credits to the person who posted...