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标题: [分享] Base64加密与解密代码FOR　ＶＢＳＣＲＩＰＴ [打印本页]
作者: chinanic    时间: 2007-10-28 15:52     标题: Base64加密与解密代码FOR　ＶＢＳＣＲＩＰＴ

  1. <%
  2. Dim Base64Chars

  4. Base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

  6. ' Functions for encoding string to Base64
  7. Public Function base64_encode(byVal strIn)
  8.     Dim c1, c2, c3, w1, w2, w3, w4, n, strOut
  9.     For n = 1 To Len(strIn) Step 3
  10.         c1 = Asc(Mid(strIn, n, 1))
  11.         c2 = Asc(Mid(strIn, n + 1, 1) + Chr(0))
  12.         c3 = Asc(Mid(strIn, n + 2, 1) + Chr(0))
  13.         w1 = Int(c1 / 4) : w2 = (c1 And 3) * 16 + Int(c2 / 16)
  14.         If Len(strIn) >= n + 1 Then
  15.             w3 = (c2 And 15) * 4 + Int(c3 / 64)
  16.         Else
  17.             w3 = -1
  18.         End If
  19.         If Len(strIn) >= n + 2 Then
  20.             w4 = c3 And 63
  21.         Else
  22.             w4 = -1
  23.         End If
  24.         strOut = strOut + mimeencode(w1) + mimeencode(w2) + _
  25.                   mimeencode(w3) + mimeencode(w4)
  26.     Next
  27.     base64_encode = strOut
  28. End Function

  30. Private Function mimeencode(byVal intIn)
  31.     If intIn >= 0 Then
  32.         mimeencode = Mid(Base64Chars, intIn + 1, 1)
  33.     Else
  34.         mimeencode = ""
  35.     End If
  36. End Function   


  39. ' Function to decode string from Base64
  40. Public Function base64_decode(byVal strIn)
  41.     Dim w1, w2, w3, w4, n, strOut
  42.     For n = 1 To Len(strIn) Step 4
  43.         w1 = mimedecode(Mid(strIn, n, 1))
  44.         w2 = mimedecode(Mid(strIn, n + 1, 1))
  45.         w3 = mimedecode(Mid(strIn, n + 2, 1))
  46.         w4 = mimedecode(Mid(strIn, n + 3, 1))
  47.         If w2 >= 0 Then _
  48.             strOut = strOut + _
  49.                 Chr(((w1 * 4 + Int(w2 / 16)) And 255))
  50.         If w3 >= 0 Then _
  51.             strOut = strOut + _
  52.                 Chr(((w2 * 16 + Int(w3 / 4)) And 255))
  53.         If w4 >= 0 Then _
  54.             strOut = strOut + _
  55.                 Chr(((w3 * 64 + w4) And 255))
  56.     Next
  57.     base64_decode = strOut
  58. End Function

  60. Private Function mimedecode(byVal strIn)
  61.     If Len(strIn) = 0 Then
  62.         mimedecode = -1 : Exit Function
  63.     Else
  64.         mimedecode = InStr(Base64Chars, strIn) - 1
  65.     End If
  66. End Function
  67. %>
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