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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")

The above is all the contents of the article "how vbs implements the base64 decryption script code". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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