Imports System.Security.Cryptography
Imports System.IO
Imports System.Text

Public Class MyFunction
    'The function used to encrypt the text
    Public Shared Function Encrypt(ByVal strText As String) As String
        Dim strEncrKey As String = "txd.v?tx"
        Dim byKey() As Byte = {}
        Dim IV() As Byte = {&H12, &H34, &H56, &H78, &H90, &HAB, &HCD, &HEF}

        Try
            byKey = System.Text.Encoding.UTF8.GetBytes(Left(strEncrKey, 8))

            Dim des As New DESCryptoServiceProvider()
            Dim inputByteArray() As Byte = Encoding.UTF8.GetBytes(strText)
            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write)
            cs.Write(inputByteArray, 0, inputByteArray.Length)
            cs.FlushFinalBlock()
            Return Convert.ToBase64String(ms.ToArray())

        Catch ex As Exception
            Return ex.Message
        End Try

    End Function

    'The function used to decrypt the text
    Public Shared Function Decrypt(ByVal strText As String) As String
        Dim sDecrKey As String = "v59!=cCD"
        Dim byKey() As Byte = {}
        Dim IV() As Byte = {&H12, &H34, &H56, &H78, &H90, &HAB, &HCD, &HEF}
        Dim inputByteArray(strText.Length) As Byte

        Try
            byKey = System.Text.Encoding.UTF8.GetBytes(Left(sDecrKey, 8))
            Dim des As New DESCryptoServiceProvider()
            inputByteArray = Convert.FromBase64String(strText)
            Dim ms As New MemoryStream()
            Dim cs As New CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write)

            cs.Write(inputByteArray, 0, inputByteArray.Length)
            cs.FlushFinalBlock()
            Dim encoding As System.Text.Encoding = System.Text.Encoding.UTF8

            Return encoding.GetString(ms.ToArray())

        Catch ex As Exception
            Return ex.Message
        End Try
    End Function
End Class