Base64 编码/加密函数/解密函数

t13564865256

'VBA Base64 编码/加密函数：
Function Base64Encode(StrA As String) As String                                  'Base64 编码
    On Error GoTo over                                                          '排错
    Dim buf() As Byte, length As Long, mods As Long
    Dim Str() As Byte
    Dim i, kk As Integer
    kk = Len(StrA) - 1
    ReDim Str(kk)
    For i = 0 To kk
        Str(i) = Asc(Mid(StrA, i + 1, 1))
    Next i
    Const B64_CHAR_DICT = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
    mods = (UBound(Str) + 1) Mod 3   '除以3的余数
    length = UBound(Str) + 1 - mods
    ReDim buf(length / 3 * 4 + IIf(mods <> 0, 4, 0) - 1)
    For i = 0 To length - 1 Step 3
        buf(i / 3 * 4) = (Str(i) And &HFC) / &H4
        buf(i / 3 * 4 + 1) = (Str(i) And &H3) * &H10 + (Str(i + 1) And &HF0) / &H10
        buf(i / 3 * 4 + 2) = (Str(i + 1) And &HF) * &H4 + (Str(i + 2) And &HC0) / &H40
        buf(i / 3 * 4 + 3) = Str(i + 2) And &H3F
    Next
    If mods = 1 Then
        buf(length / 3 * 4) = (Str(length) And &HFC) / &H4
        buf(length / 3 * 4 + 1) = (Str(length) And &H3) * &H10
        buf(length / 3 * 4 + 2) = 64
        buf(length / 3 * 4 + 3) = 64
    ElseIf mods = 2 Then
        buf(length / 3 * 4) = (Str(length) And &HFC) / &H4
        buf(length / 3 * 4 + 1) = (Str(length) And &H3) * &H10 + (Str(length + 1) And &HF0) / &H10
        buf(length / 3 * 4 + 2) = (Str(length + 1) And &HF) * &H4
        buf(length / 3 * 4 + 3) = 64
    End If
    For i = 0 To UBound(buf)
        Base64Encode = Base64Encode + Mid(B64_CHAR_DICT, buf(i) + 1, 1)
    Next
over:
End Function

'VBA Base64 解码/解密函数：
Function Base64Decode(B64 As String) As String                                  'Base64 解码
    On Error GoTo over                                                          '排错
    Dim OutStr() As Byte, i As Long, j As Long
    Const B64_CHAR_DICT = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
    If InStr(1, B64, "=") <> 0 Then B64 = Left(B64, InStr(1, B64, "=") - 1)     '判断Base64真实长度,除去补位
    Dim kk, length As Long, mods As Long
    mods = Len(B64) Mod 4
    length = Len(B64) - mods
    ReDim OutStr(length / 4 * 3 - 1 + Switch(mods = 0, 0, mods = 2, 1, mods = 3, 2))
    For i = 1 To length Step 4
        Dim buf(3) As Byte
        For j = 0 To 3
            buf(j) = InStr(1, B64_CHAR_DICT, Mid(B64, i + j, 1)) - 1            '根据字符的位置取得索引值
        Next
        OutStr((i - 1) / 4 * 3) = buf(0) * &H4 + (buf(1) And &H30) / &H10
        OutStr((i - 1) / 4 * 3 + 1) = (buf(1) And &HF) * &H10 + (buf(2) And &H3C) / &H4
        OutStr((i - 1) / 4 * 3 + 2) = (buf(2) And &H3) * &H40 + buf(3)
    Next
    If mods = 2 Then
        OutStr(length / 4 * 3) = (InStr(1, B64_CHAR_DICT, Mid(B64, length + 1, 1)) - 1) * &H4 + ((InStr(1, B64_CHAR_DICT, Mid(B64, length + 2, 1)) - 1) And &H30) / 16
    ElseIf mods = 3 Then
        OutStr(length / 4 * 3) = (InStr(1, B64_CHAR_DICT, Mid(B64, length + 1, 1)) - 1) * &H4 + ((InStr(1, B64_CHAR_DICT, Mid(B64, length + 2, 1)) - 1) And &H30) / 16
        OutStr(length / 4 * 3 + 1) = ((InStr(1, B64_CHAR_DICT, Mid(B64, length + 2, 1)) - 1) And &HF) * &H10 + ((InStr(1, B64_CHAR_DICT, Mid(B64, length + 3, 1)) - 1) And &H3C) / &H4
    End If
    For i = 0 To UBound(OutStr)
        Base64Decode = Base64Decode & Chr(OutStr(i))
    Next i                                                       '读取解码结果
over:
End Function

有帮助的多给鲜花，谢谢大家了。

mtxj

好东西 但不会用 菜鸟一枚  能都举个实例

大笨豆6

这也是好东西，收藏 了

大笨豆6

收藏 了

liangdx

非常不错，值得加赞

xyzlb

感谢，正好用上

硅谷少年

亲测可用，解决了我的问题，非常感谢。

yuk_yu

谢谢分享！！