توضیح در مورد کد - نهان نگاری

[terrorhell]

سلام دوستان عزیز این کد در مورد نهان نگاری ( مخفی کردن متن در عکس) می باشد ، ممنون میشم توضیح بدید این کد با چه روشی داره نهان نگاری رو انجام میده مرسی

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim Ready As Boolean = True
Dim PicFileStream As System.IO.FileStream
Try
PicFileStream = PicBuffer.OpenRead
Catch ex As Exception
Ready = False
MsgBox("Please load a picture before clicking this button", MsgBoxStyle.Critical, "Error")
End Try
If Ready = True Then
Dim PicBytes As Long = PicFileStream.Length
Dim PicExt As String = PicBuffer.Extension
Dim PicByteArray(PicBytes) As Byte
PicFileStream.Read(PicByteArray, 0, PicBytes)
Dim SentinelString() As Byte = {73, 116, 83, 116, 97, 114, 116, 115, 72, 101, 114, 101}
If RadioButton1.Checked = True Then
Dim PlainText As String = TextBox1.Text
Dim PlainTextByteArray(PlainText.Length) As Byte
For i As Integer = 0 To (PlainText.Length - 1)
PlainTextByteArray(i) = CByte(AscW(PlainText.Chars(i)))
Application.DoEvents()
Next
Dim PicAndText(PicBytes + PlainText.Length + SentinelString.Length) As Byte
For t As Long = 0 To (PicBytes - 1)
PicAndText(t) = PicByteArray(t)
Next
Dim count As Integer = 0
For r As Long = PicBytes To (PicBytes + (SentinelString.Length) - 1)
PicAndText(r) = SentinelString(count)
count += 1
Next
count = 0
For q As Long = (PicBytes + SentinelString.Length) To (PicBytes + SentinelString.Length + PlainText.Length - 1)
PicAndText(q) = PlainTextByteArray(count)
count += 1
Next
buildPic.ShowDialog()
Dim NewFileName As String = buildPic.FileName
My.Computer.FileSystem.WriteAllBytes(NewFileName, PicAndText, False)


ElseIf RadioButton2.Checked Then
TextBox3.Clear()
Dim OutterSearch, InnerSearch, StopSearch As Boolean
OutterSearch = True
InnerSearch = True
StopSearch = False
Dim count As Long = 0
Dim leftCounter As Long
Dim rightCounter As Integer
leftCounter = 0
rightCounter = 0
Do While (count < (PicBytes - SentinelString.Length) And StopSearch = False)
If (PicByteArray(count) = SentinelString(0)) Then
leftCounter = count + 1
rightCounter = 1
InnerSearch = True
Do While (InnerSearch = True) And (rightCounter < SentinelString.Length) _
And (leftCounter < PicByteArray.Length)
If (PicByteArray(leftCounter) = SentinelString(rightCounter)) Then
rightCounter += 1
leftCounter += 1
If (rightCounter = (SentinelString.Length - 1)) Then
StopSearch = True
End If
Else
InnerSearch = False
count += 1
End If
Loop
Else
count += 1
End If
Loop
If StopSearch = True Then
'leftCounter contains the starting string that is being retrieved
Do While (leftCounter < PicBytes)
'Bytes need to be converted to an integer
'then to an unicode character which will be the plaintext
TextBox3.AppendText(ChrW(CInt(PicByteArray(leftCou nter))))
leftCounter += 1
Loop
Else
TextBox3.Text = "The Picture does not contain any text"
End If


End If
End If


End Sub

[terrorhell]

دوستان وی بی کار ممنون میشم راهنمایی کنید

[terrorhell]

حد اقل بگید این خط کد کارش چیه ::

Dim SentinelString() As Byte = {73, 116, 83, 116, 97, 114, 116, 115, 72, 101, 114, 101}