[Débutant] Cryptage sur VB.Net et decryptage

BONJOUR à tous
je trouve ce code de cryptage aes 128
mais je souhaite faire les décryptage :calim2:
voici le code et merci a tous
Code:
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Dim KeyAES As String = "Bonjour"
 
 Private Function Crypter(ByVal pData As String, ByVal pKey As String) As String
        'Création des objets de crypto
        Dim AES As New System.Security.Cryptography.RijndaelManaged
        Dim Md5 As New System.Security.Cryptography.MD5CryptoServiceProvider
 
        'Données clair string vers données clair byte
        Dim DataClairByte As Byte() = System.Text.Encoding.UTF8.GetBytes(pData)
 
        'Key string vers key byte
        Dim KeyByte As Byte() = System.Text.Encoding.UTF8.GetBytes(pKey)
 
        'Hashage de la key byte
        Dim KeyHashByte As Byte() = Md5.ComputeHash(KeyByte)
 
        'Key hash byte vers key hash hex
        Dim StringBuilder As New System.Text.StringBuilder
        For i As Integer = 0 To KeyHashByte.Length - 1
            StringBuilder.AppendFormat("{0:X2}", KeyHashByte(i))
        Next
        Dim KeyHashHex As String = StringBuilder.ToString.ToLower
 
        'Key / IV
        Dim KeyUseHashHex As String = ""
        Dim IVHex As String = ""
        For i As Integer = 0 To KeyHashHex.Length - 1
            If i Mod 2 = 0 Then
                KeyUseHashHex = KeyUseHashHex + KeyHashHex(i)
            Else
                IVHex = IVHex + KeyHashHex(i)
            End If
        Next
        Dim Key As Byte() = System.Text.Encoding.UTF8.GetBytes(KeyUseHashHex)
        Dim IV As Byte() = System.Text.Encoding.UTF8.GetBytes(IVHex)
 
        'Cryptage
        AES.KeySize = 128
        AES.Mode = System.Security.Cryptography.CipherMode.CBC
        AES.Key = Key
        AES.IV = IV
        Dim Encrypteur As System.Security.Cryptography.ICryptoTransform = AES.CreateEncryptor()
        Dim MemoryStream As New System.IO.MemoryStream
        Dim CryptoStream As New System.Security.Cryptography.CryptoStream(MemoryStream, Encrypteur, System.Security.Cryptography.CryptoStreamMode.Write)
        CryptoStream.Write(DataClairByte, 0, DataClairByte.Length)
        CryptoStream.FlushFinalBlock()
        Dim DataCryptByte As Byte() = MemoryStream.ToArray
 
        'Liveration des ressources
        MemoryStream.Close()
        CryptoStream.Close()
 
        'Data Crypt Byte ver Data Crypt String
        Dim DataCryptString As String = System.Convert.ToBase64String(DataCryptByte)
 
        Return DataCryptString
    End Function