Bruteforce in .NET
A VB.Net class on how to perform a string based permutation. Also known as "bruteforce". Good to have. It's not around on the net, so i chose to publish it.
Option Explicit On
Option Strict On
Public Class Permutation
Private _Charset As String = vbNullString
Private _IndexArray(_Max) As Integer
Private _Max As Short = &H1
Private _Min As Short = &H0
Private _TimePerCalculation As Double = &H0
Private _Estimater As UInt16 = &H0
Private _Watch As New Stopwatch
Public Sub New(ByVal Charset As String, ByVal Max As Short, _
ByVal Min As Short)
_Charset = Charset
_Max = Max
_Min = Min
ReDim _IndexArray(_Max)
For Nullifier As Integer = &H0 To (_Min - &H1)
_IndexArray(Nullifier) = &H1
Next
_Watch.Start()
End Sub
Public Sub Add()
_IndexArray(&H0) = _IndexArray(&H0) + &H1
For Index As Short = &H0 To CShort(_Max - &H1)
If (_IndexArray(Index) > &H0) And _
(_IndexArray(Index) > Len(_Charset)) Then
_IndexArray(Index) = &H1
_IndexArray(Index + &H1) = _IndexArray(Index + &H1) + &H1
End If
Next Index
End Sub
Public Function GenerateString(Optional ByVal AddToNextTurn As Boolean = True) As String
_Estimater = CUShort(_Estimater + &H1)
If _Estimater Mod UInt16.MaxValue = &H0 Then
_TimePerCalculation = (_Watch.ElapsedMilliseconds / UInt16.MaxValue)
_Watch.Reset()
_Watch.Start()
_Estimater = &H0
End If
Dim Result As String = vbNullString
For Index As Short = &H0 To _Max
If _IndexArray(Index) <> &H0 Then
Result = Result & Mid(_Charset, _IndexArray(Index), &H1)
End If
Next
If AddToNextTurn = True Then Add()
Return Result
End Function
Public ReadOnly Property GetExitValue() As Double
Get
Dim Result As Double = &H0
For Index As Integer = _Min To _Max
Result += (Len(_Charset) ^ Index)
Next
Return Result
End Get
End Property
Public ReadOnly Property GetExitString() As String
Get
Return New String(CChar(_Charset.Substring(_Charset.Length - &H1, &H1)), _Max)
End Get
End Property
Public ReadOnly Property TimePerCalculation() As Double
Get
Return _TimePerCalculation
End Get
End Property
Public Function MakeMD5(ByVal Word As String) As String
Dim MD5 As New System.Security.Cryptography.MD5CryptoServiceProvider
Dim ByteHash() As Byte
Dim Result As String = vbNullString
ByteHash = MD5.ComputeHash(System.Text.Encoding.ASCII.GetBytes(Word))
For Index As Integer = &H0 To &HF
Result &= ByteHash(Index).ToString("x").PadLeft(&H2, CChar("0"))
Next
Return Result
End Function
End Class
The New sub specifies the charset, the minimum and maximum length to use.
Every time you call the GenerateString() function, it will return a new permutated value.
Also, in order to determine when you're done or not. You can use neither the GetExitString() function, and see if it matches with the GenerateString() or if the number of permutations made by GenerateString() is equal to the GetExitValue().
Edit:
Press here to download the sourcecode.
Enough said. Now it's documented!
Hey, I'm Fredrik. I'm from Sweden, born 1990, and I got a huge interest for information technology and information security. So far, I've been studying for three years at the Internation IT College of Sweden and one year at the Royal Institute of Technology (Kista, Sweden). I'm one of the Co-Founders of Detectify. I'm working closely together with the swedish firm Young & Skilled. ...Not to forget, I'm the previous founder of Arctic Security. If you wish to contact me, please email me at h@ackack.net or follow me on twitter @Almroot.