转贴：

感到使用VB等语言的兄弟调用这些现成的算法比较麻烦，特写个DLL，给大家调用，呵呵。。。。。。。。。
MIME也就是BASE64，其它的就不多说了。。。。。。。。
下面的源码是VB.NET写的,把其中的源码拷贝到VB6中也可编译。
把DLL拷贝到所写的VB工程目录下，然后把下面的声明加进去，就可调用了。。。。。。

Public Class Form1
  Declare Function EncodeMIME Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function DecodeMIME Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function EncodeXXE Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function DecodeXXE Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function EncodeUUE Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function DecodeUUE Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long
  Declare Function MD5 Lib "CryptPrj.dll" (ByVal lpszSource As String, ByVal lpszDst As String) As Long

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim str1 As String
    Dim str2 As String
    str1 = Space(255)
    str2 = TextBox1.Text
    Select Case ComboBox1.SelectedIndex
        Case 0
          EncodeMIME(str2, str1)
        Case 1
          EncodeXXE(str2, str1)
        Case 2
          EncodeUUE(str2, str1)
        Case 3
          MD5(str2, str1)
    End Select
    TextBox2.Text = str1
  End Sub

  Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    Dim str1 As String
    Dim str2 As String

    str1 = Space(255)
    str2 = TextBox1.Text
    Select Case ComboBox1.SelectedIndex
        Case 0
          DecodeMIME(str2, str1)
        Case 1
          DecodeXXE(str2, str1)
        Case 2
          DecodeUUE(str2, str1)
        Case 3
          str1 = ""
          MsgBox("不支持MD5逆运算")
    End Select
    TextBox2.Text = str1
  End Sub

  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    ComboBox1.SelectedIndex = 0
  End Sub
End Class

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