加密程序串错误

Question

所以，即时制作一个简单的加密程序，这是该算法：

1. 例：炭：一个;键：10000
2. 从控制数减去ASCII数字一零零零年至1097年= 9903
3. 转换结果为十六进制，然后进入一个字符串9903 = 26AF
4. 拆分六角导致成的两个数字26基团，AF
5. 转换分裂的十六进制值为ASCII 26 = 38（&）AF = 175（¯）你的水库ult会是：&

问题是，有时（代码如下），根据加密密钥，加密结果出来所有磨损和解密功能将无法正常工作。我做了测试，我知道问题在于加密功能，但我不知道在哪里。下面的代码：

Option Strict On 

Imports System.Numerics 

Public Class MainF 

    'tick for random keys 
    Dim objRandom As New System.Random(CType(System.DateTime.Now.Ticks Mod System.Int32.MaxValue, Integer)) 

    Private Function AsciiToChars(ByVal nums As IEnumerable(Of Integer)) As Char() 
     'converts ASCII value to char 
     Return (From c In nums Select Chr(c)).ToArray 
    End Function 

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 

     'set random key 
     KeyE.Text = CStr(GetRandomNumber(10000, 99999)) 
     KeyD.Text = KeyE.Text 
    End Sub 

    Public Function GetRandomNumber(Optional ByVal Low As Integer = 1, Optional ByVal High As Integer = 100) As Integer 

     'generate a randomic number, for the random key 
     Return objRandom.Next(Low, High + 1) 
    End Function 

    Private Sub GenKey_Click(sender As Object, e As EventArgs) Handles GenKey.Click 

     'renew key 
     KeyE.Text = CStr(GetRandomNumber(10000, 99999)) 
     Dim tmptxt As String 
     tmptxt = En.Text 
     En.Text = "" 
     En.Text = tmptxt 
     KeyD.Text = KeyE.Text 
     tmptxt = String.Empty 
    End Sub 

    Sub En_TextChanged(sender As Object, e As EventArgs) Handles En.TextChanged 

     'encrypt 
     If (String.IsNullOrEmpty(En.Text)) Then 
      Enres.Text = "" 
     Else 
      Dim key As Integer = CInt(KeyE.Text) 
      Dim chars() As Char = En.Text.ToCharArray 
      Dim ints(chars.Length) As Integer 
      Dim hex(chars.Length) As String 
      Dim fex As String = "" 
      Dim Mlist As New List(Of String) 

      For Loop0 As Integer = 0 To chars.Length - 1 
       ints(Loop0) = key - Asc(chars(Loop0)) 
       hex(Loop0) = Conversion.Hex(ints(Loop0)) 
       fex &= hex(Loop0) 
      Next 

      If fex.Length Mod 2 <> 0 Then 'Mod returns the remainder of a division calculation. It will be 0 if the number is even. 
       fex = "0" & fex 'This will change "6AF" to "06AF" 
      End If 

      For x As Integer = 0 To fex.Length - 1 Step 2 
       Mlist.Add(fex.Substring(x, 2)) 
      Next 

      Dim fdec(CInt((fex.Length - 2)/2)) As Integer 
      Dim fstr As String 

      For y As Integer = 0 To fdec.Length - 1 
       fdec(y) = CInt(Val("&H" & Mlist(y))) 
      Next 

      fstr = AsciiToChars(fdec) 
      Enres.Text = fstr 
     End If 
    End Sub 

    Private Sub De_TextChanged(sender As Object, e As EventArgs) Handles De.TextChanged 

     'decrypt 
     If (String.IsNullOrEmpty(De.Text)) Then 
      DeRes.Text = "" 
     Else 
      Dim final As String = "" 
      Dim key As Integer 
      key = CInt(KeyD.Text) 
      Dim FSTR As String = De.Text 
      Dim chars() As Char = FSTR.ToCharArray 
      Dim hexsub(chars.Length) As String 
      Dim ints(chars.Length) As String 
      Dim finalhex As String 

      For loop1 As Integer = 0 To chars.Length - 1 
       ints(loop1) = CStr(Asc(chars(loop1))) 
       hexsub(loop1) = Hex(ints(loop1)) 
      Next   

      finalhex = Join(hexsub, String.Empty) 

      If finalhex.Length Mod 4 = 0 Then 
       Dim newlist As New List(Of String) 

       For x As Integer = 0 To finalhex.Length - 1 Step 4 
        newlist.Add(finalhex.Substring(x, 4)) 
       Next 

       Dim sourceNUM(newlist.Count) As Int32 
       Dim finalascii(newlist.Count) As Int32 
       Dim finalchar(newlist.Count) As Char 
       key = CInt(KeyD.Text) 

       For b As Int32 = 0 To newlist.Count - 1 
        sourceNUM(b) = Convert.ToInt32(newlist(b), 16) 
        finalascii(b) = key - sourceNUM(b) 

        If finalascii(b) >= 32 And finalascii(b) <= 255 Then 
         finalchar(b) = Chr(finalascii(b)) 
         final &= finalchar(b) 
        Else : final = "Invalid Input" 
        End If 
       Next 

       DeRes.Text = final 
      Else 
       DeRes.Text = "" 
      End If 
     End If 
    End Sub 

    Private Sub KeyE_TextChanged(sender As Object, e As KeyEventArgs) Handles KeyE.KeyDown 

     'future idea, enter key will run encription sub 
     If e.KeyCode = Keys.Enter Then 
      e.SuppressKeyPress = True 
     End If 
    End Sub 
End Class 

Answer 1

的问题是，有时（下面的代码），根据不同的加密 密钥，加密结果出来一切磨损和解密 功能不会工作。

你，我可以找到主要的问题是，有时你路过不可显示的代码经过加密的字符串，然后将其视为零，而这又会使解密算法失败

您可能需要图取出什么范围的键会给出错误的值并将这些键过滤掉或使用字节数组而不是字符串