Explication de code Crypt

Question

je vous demande de m'aider sur le code suivant avec un Explication aisse
*************************************le code***
Option Explicit

Private Const CodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-/"
Public Enum CryptMethods
  cmNumberOfTime
  cmRaiseLenght
End Enum
Private Enum BitCoding
  bc6Bits = 5
  bc8Bits = 7
End Enum
Public Function CryptMsg(ByVal Msg As String, _
                         Optional ByVal CryptMethod As CryptMethods = cmNumberOfTime, _
                         Optional ByRef CryptLimit As Integer = 0) As String
Dim BS As String
Dim i As Integer

  If CryptMethod = cmNumberOfTime Then
    For i = 1 To CryptLimit
      BS = GetBitString(Msg, bc8Bits)
      Msg = GetConvertedString(BS, bc6Bits)
    Next
    CryptMsg = Msg
  Else
    i = 0
    While Len(Msg) < CryptLimit
      BS = GetBitString(Msg, bc8Bits)
      Msg = GetConvertedString(BS, bc6Bits)
      If Len(Msg) <CryptLimit Then CryptMsg Msg: i = i + 1
    Wend
    CryptLimit = i
  End If
End Function


Public Function UncryptMsg(ByVal Msg As String, _
                Optional ByVal UncryptRepeat As Integer = 1) As String
Dim BS As String

  UncryptMsg = Msg
  While UncryptRepeat > 0
    BS = GetBitString(UncryptMsg, bc6Bits)
    BS = Mid$(BS, 1, (Len(BS) \ 8) * 8)
    UncryptMsg = GetConvertedString(BS, bc8Bits)
    UncryptRepeat = UncryptRepeat - 1
  Wend
End Function

Private Function GetBitString(ByVal Msg As String, _
                              ByVal BitPerChar As BitCoding) As String
Dim LetterIdx As Integer
Dim AscLetter As Integer
Dim BitIdx As Integer

  For LetterIdx = 1 To Len(Msg)
    If BitPerChar = bc8Bits Then
      AscLetter = Asc(Mid$(Msg, LetterIdx, 1))
    Else
      AscLetter = InStr(CodeChars, Mid$(Msg, LetterIdx, 1)) - 1
    End If
    For BitIdx = BitPerChar To 0 Step -1
      If AscLetter And 2 ^ BitIdx Then
        GetBitString = GetBitString & "1"
      Else
        GetBitString = GetBitString & "0"
      End If
    Next
  Next
End Function

Private Function GetConvertedString(ByVal BitString As String, _
                                    ByVal BitPerChar As BitCoding) As String
Dim LetterIdx As Integer
Dim AscLetter As Integer
Dim BitIdx As Integer

  For LetterIdx = 1 To Len(BitString) Step BitPerChar + 1
    AscLetter = 0
    For BitIdx = 0 To BitPerChar
      If Mid$(BitString, LetterIdx + BitIdx, 1) = "1" Then
        AscLetter = AscLetter Or (2 ^ (BitPerChar - BitIdx))
      End If
    Next
    If BitPerChar = bc8Bits Then
      GetConvertedString = GetConvertedString & Chr$(AscLetter)
    Else
      GetConvertedString = GetConvertedString & Mid$(CodeChars, AscLetter + 1, 1)
    End If
  Next
End Function
********************************fin************

cs_Jack · Answer

BONJOUR aussi
Question trop vague.
Pose la question à l'auteur du code.
A chaque question sur une instruction, tape la touche F1 et regarge dans l'aide
Apprends à débugguer le code avec les touches F9 et F8.

Vala
Jack, MVP VB
NB : Je ne répondrai pas aux messages privés

Le savoir est la seule matière qui s'accroit quand on la partage (Socrate)

Explication de code Crypt

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