asp base64类库，asp.net可解码

 const BASE_64_MAP_INIT = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
   dim newline
   dim Base64EncMap(63)
   dim Base64DecMap(127)
   '初始化函数
   PUBLIC SUB initCodecs()
'。。。。
   END SUB
   'Base64加密函数
   PUBLIC FUNCTION base64Encode(plain)
'。。。。
   END FUNCTION
   'Base64解密函数
   PUBLIC FUNCTION base64Decode(scrambled)
   END FUNCTION

 byte[] bytes = Convert.FromBase64String("base64编码字符串");
Response.Write(encoding.GetString(bytes));

Function Base64Encode(sText)
    Dim oXML, oNode
    Set oXML = CreateObject("Msxml2.DOMDocument.3.0")
    Set oNode = oXML.CreateElement("base64")
    oNode.dataType = "bin.base64"
    oNode.nodeTypedValue =Stream_StringToBinary(sText)
    Base64Encode = oNode.text
    Set oNode = Nothing
    Set oXML = Nothing
End Function
Function Base64Decode(ByVal vCode)
    Dim oXML, oNode
    Set oXML = CreateObject("Msxml2.DOMDocument.3.0")
    Set oNode = oXML.CreateElement("base64")
    oNode.dataType = "bin.base64"
    oNode.text = vCode
    Base64Decode = Stream_BinaryToString(oNode.nodeTypedValue)
    Set oNode = Nothing
    Set oXML = Nothing
End Function
'Stream_StringToBinary Function
'2003 Antonin Foller, http://www.motobit.com
'Text - string parameter To convert To binary data
Function Stream_StringToBinary(Text)
  Const adTypeText = 2
  Const adTypeBinary = 1
  'Create Stream object
  Dim BinaryStream 'As New Stream
  Set BinaryStream = CreateObject("ADODB.Stream")
  'Specify stream type - we want To save text/string data.
  BinaryStream.Type = adTypeText
  'Specify charset For the source text (unicode) data.
  BinaryStream.CharSet = "us-ascii"
  'Open the stream And write text/string data To the object
  BinaryStream.Open
  BinaryStream.WriteText Text
  'Change stream type To binary
  BinaryStream.Position = 0
  BinaryStream.Type = adTypeBinary
  'Ignore first two bytes - sign of
  BinaryStream.Position = 0
  'Open the stream And get binary data from the object
  Stream_StringToBinary = BinaryStream.Read
  Set BinaryStream = Nothing
End Function
'Stream_BinaryToString Function
'2003 Antonin Foller, http://www.motobit.com
'Binary - VT_UI1 | VT_ARRAY data To convert To a string 
Function Stream_BinaryToString(Binary)
  Const adTypeText = 2
  Const adTypeBinary = 1
  'Create Stream object
  Dim BinaryStream 'As New Stream
  Set BinaryStream = CreateObject("ADODB.Stream")
  'Specify stream type - we want To save binary data.
  BinaryStream.Type = adTypeBinary
  'Open the stream And write binary data To the object
  BinaryStream.Open
  BinaryStream.Write Binary
  'Change stream type To text/string
  BinaryStream.Position = 0
  BinaryStream.Type = adTypeText
  'Specify charset For the output text (unicode) data.
  BinaryStream.CharSet = "us-ascii"
  'Open the stream And get text/string data from the object
  Stream_BinaryToString = BinaryStream.ReadText
  Set BinaryStream = Nothing
End Function