VB.NET 使用 DES / AES 字串加密

參考資料：[C#.NET] 字串及檔案 利用 DES / AES 演算法加解密

此篇參考上方的參考資料，並翻成VB.NET。

Imports Microsoft.VisualBasic
Imports System.Security.Cryptography '加密
Imports System.Text
Imports System.IO
Public Class EnDe
'字串長度必須為8
    Dim DesKey As String = "abc!@#df", DesIv As String = "+_)xyz*&"

    Public Sub New()
    End Sub

    '參考資料https://dotblogs.com.tw/yc421206/archive/2012/04/18/71609.aspx
'source:要加密的字串
    Function DesEncrypt(ByVal source As String) As String
        Dim des As DESCryptoServiceProvider = New DESCryptoServiceProvider()
        Dim key() As Byte = Nothing
        Dim iv() As Byte = Nothing
        Dim dataByteArray() As Byte = Nothing

        key = Encoding.ASCII.GetBytes(DesKey)
        iv = Encoding.ASCII.GetBytes(DesIv)
        dataByteArray = Encoding.UTF8.GetBytes(source)

        des.Key = key
        des.IV = iv

        Dim encrypt As String = String.Empty
        Using ms As MemoryStream = New MemoryStream()
            Try
                Using cs As CryptoStream = New CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write)
                    cs.Write(dataByteArray, 0, dataByteArray.Length)
                    cs.FlushFinalBlock()

                    Dim sb As StringBuilder = New StringBuilder()
                    For Each b As Byte In ms.ToArray()
                        sb.AppendFormat("{0:X2}", b)
                    Next
                    encrypt = sb.ToString()
                End Using
            Catch ex As Exception
                encrypt = "error"
            End Try
        End Using

        Return encrypt
    End Function

    '解密 encrypt:要解密的字串
    Function DesDecrypt(ByVal encrypt As String) As String

        Dim a1 As Integer = ((encrypt.Length) / 2)
        a1 = a1 - 1
        Dim dataByteArray(a1) As Byte

        For x1 As Integer = 0 To a1
            Dim i As Integer = Convert.ToInt32(encrypt.Substring(x1 * 2, 2), 16)
            dataByteArray(x1) = CByte(i)
        Next

        Dim des As DESCryptoServiceProvider = New DESCryptoServiceProvider()
        Dim key() As Byte = Nothing
        Dim iv() As Byte = Nothing

        key = Encoding.ASCII.GetBytes(DesKey)
        iv = Encoding.ASCII.GetBytes(DesIv)

        des.Key = key
        des.IV = iv

        Dim DesString As String = String.Empty
        Using ms As MemoryStream = New MemoryStream()
            Try
                Using cs As CryptoStream = New CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write)
                    cs.Write(dataByteArray, 0, dataByteArray.Length)
                    cs.FlushFinalBlock()
                    DesString = Encoding.UTF8.GetString(ms.ToArray())
                End Using
            Catch ex As Exception
                DesString = "error"
            End Try
        End Using
        Return DesString
    End Function

End Class

用ASP.NET WebForm來測試，畫面很簡單，兩個TextBox、兩個Button(分別是加密、解密)，程式碼如下。

Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim str_en As String = String.Empty
        Dim ed As EnDe
        ed = New EnDe()
        str_en = ed.DesEncrypt(TextBox1.Text)
        Response.Write("[" & str_en & "]")

    End Sub
    Protected Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim str_de As String = String.Empty
        Dim ed As EnDe
        ed = New EnDe()
        str_de = ed.DesDecrypt(TextBox2.Text)
        Response.Write("[" & str_de & "]")
    End Sub
End Class

執行過程，如下：