Base64編碼解碼小工具1.0 綠色免費版

這是一個Base64編碼、解碼小工具（可破解迅雷下載地址）。采用本站原創(chuàng)的VB6下Base64編碼解碼算法。

Base64說明

Base64是網(wǎng)絡(luò)上最常見的用于傳輸8Bit字節(jié)代碼的編碼方式之一，可用于在HTTP環(huán)境下傳遞較長的標識信息。在其他應(yīng)用程序中，也常常需要把二進制數(shù)據(jù)編碼為適合放在URL（包括隱藏表單域）中的形式。此時，采用Base64編碼不僅比較簡短，同時也具有不可讀性，即所編碼的數(shù)據(jù)不會被人用肉眼所直接看到。

程序源碼：

Option Explicit
Private Const cstBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
Private arrBase64() As String
'00100001 00100001 00100001             --源碼
'00001000 00010010 00000100 00100001    --Base64碼

Public Function Base64Encode(strSource As String) As String
On Error Resume Next
'適用于中、英文的Base64編碼/解碼VB6超精簡版
If UBound(arrBase64) = -1 Then
    arrBase64 = Split(StrConv(cstBase64, vbUnicode), vbNullChar)
End If
Dim arrB() As Byte, bTmp(2)  As Byte, bT As Byte
Dim I As Long, J As Long
arrB = StrConv(strSource, vbFromUnicode)

J = UBound(arrB)
For I = 0 To J Step 3
    Erase bTmp
    bTmp(0) = arrB(I + 0)
    bTmp(1) = arrB(I + 1)
    bTmp(2) = arrB(I + 2)
   
    bT = (bTmp(0) And 252) / 4
    Base64Encode = Base64Encode & arrBase64(bT)
   
    bT = (bTmp(0) And 3) * 16
    bT = bT + bTmp(1) / 16
    Base64Encode = Base64Encode & arrBase64(bT)
   
    bT = (bTmp(1) And 15) * 4
    bT = bT + bTmp(2) / 64
    If I + 1 <= J Then
        Base64Encode = Base64Encode & arrBase64(bT)
    Else
        Base64Encode = Base64Encode & "="
    End If
   
    bT = bTmp(2) And 63
    If I + 2 <= J Then
        Base64Encode = Base64Encode & arrBase64(bT)
    Else
        Base64Encode = Base64Encode & "="
    End If
Next
End Function

Public Function Base64Decode(strEncoded As String) As String
'適用于中、英文的Base64編碼/解碼VB6超精簡版
On Error Resume Next
Dim arrB() As Byte, bTmp(3)  As Byte, bT As Long, bRet() As Byte
Dim I As Long, J As Long
arrB = StrConv(strEncoded, vbFromUnicode)
J = InStr(strEncoded & "=", "=") - 2
ReDim bRet(J - J / 4 - 1)
For I = 0 To J Step 4
    Erase bTmp
    bTmp(0) = (InStr(cstBase64, Chr(arrB(I))) - 1) And 63
    bTmp(1) = (InStr(cstBase64, Chr(arrB(I + 1))) - 1) And 63
    bTmp(2) = (InStr(cstBase64, Chr(arrB(I + 2))) - 1) And 63
    bTmp(3) = (InStr(cstBase64, Chr(arrB(I + 3))) - 1) And 63
   
    bT = bTmp(0) * 2 ^ 18 + bTmp(1) * 2 ^ 12 + bTmp(2) * 2 ^ 6 + bTmp(3)
   
    bRet((I / 4) * 3) = bT / 65536
    bRet((I / 4) * 3 + 1) = (bT And 65280) / 256
    bRet((I / 4) * 3 + 2) = bT And 255
Next
Base64Decode = StrConv(bRet, vbUnicode)
End Function