How to implement base64 decryption script Code by vbs
This article mainly introduces vbs how to achieve base64 decryption script code, the article is very detailed, has a certain reference value, interested friends must read it!
The code is as follows:
Function fDecode (sStringToDecode)
'This function will decode a Base64 encoded string and returns the decoded string.
'This becomes usefull when attempting to hide passwords from prying eyes.
Const CharList = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
Dim iDataLength, sOutputString, iGroupInitialCharacter
SStringToDecode = Replace (sStringToDecode, vbCrLf, "), vbTab,"), ",")
IDataLength = Len (sStringToDecode)
If iDataLength Mod 4 0 Then
FDecode = "Bad string passed to fDecode () function."
Exit Function
End If
For iGroupInitialCharacter = 1 To iDataLength Step 4
Dim iDataByteCount, iCharacterCounter, sCharacter, iData, iGroup, sPreliminaryOutString
IDataByteCount = 3
IGroup = 0
For iCharacterCounter = 0 To 3
SCharacter = Mid (sStringToDecode, iGroupInitialCharacter + iCharacterCounter, 1)
If sCharacter = "=" Then
IDataByteCount = iDataByteCount-1
IData = 0
Else
IData = InStr (1, CharList, sCharacter, 0)-1
If iData =-1 Then
FDecode = "Bad string passed to fDecode () function."
Exit Function
End If
End If
IGroup = 64 * iGroup + iData
Next
IGroup = Hex (iGroup)
IGroup = String (6-Len (iGroup), "0") & iGroup
SPreliminaryOutString = Chr (CByte ("& H" & Mid (iGroup, 1,2)) & Chr (CByte ("& H" & Mid (iGroup, 3,2)) & Chr (CByte ("& H" & Mid (iGroup, 5,2)
SOutputString = sOutputString & Left (sPreliminaryOutString, iDataByteCount)
Next
FDecode = sOutputString
End Function
Base64 test code:
The code is as follows:
Function fDecode (sStringToDecode)
'This function will decode a Base64 encoded string and returns the decoded string.
'This becomes usefull when attempting to hide passwords from prying eyes.
Const CharList = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
Dim iDataLength, sOutputString, iGroupInitialCharacter
SStringToDecode = Replace (sStringToDecode, vbCrLf, "), vbTab,"), ",")
IDataLength = Len (sStringToDecode)
If iDataLength Mod 4 0 Then
FDecode = "Bad string passed to fDecode () function."
Exit Function
End If
For iGroupInitialCharacter = 1 To iDataLength Step 4
Dim iDataByteCount, iCharacterCounter, sCharacter, iData, iGroup, sPreliminaryOutString
IDataByteCount = 3
IGroup = 0
For iCharacterCounter = 0 To 3
SCharacter = Mid (sStringToDecode, iGroupInitialCharacter + iCharacterCounter, 1)
If sCharacter = "=" Then
IDataByteCount = iDataByteCount-1
IData = 0
Else
IData = InStr (1, CharList, sCharacter, 0)-1
If iData =-1 Then
FDecode = "Bad string passed to fDecode () function."
Exit Function
End If
End If
IGroup = 64 * iGroup + iData
Next
IGroup = Hex (iGroup)
IGroup = String (6-Len (iGroup), "0") & iGroup
SPreliminaryOutString = Chr (CByte ("& H" & Mid (iGroup, 1,2)) & Chr (CByte ("& H" & Mid (iGroup, 3,2)) & Chr (CByte ("& H" & Mid (iGroup, 5,2)
SOutputString = sOutputString & Left (sPreliminaryOutString, iDataByteCount)
Next
FDecode = sOutputString
End Function
Msgbox fDecode ("d3d3LmpiNTEubmV0")
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