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Entropy

Problems with decryption of the file, encrypted with $CALG_RC4

7 posts in this topic

Hi!

Strange thing happens.

My script generates a result file, and then encrypts it with _Crypt_EncryptFile(), from Crypt.au3 UDF

If i decrypt it with _Crypt_DecryptFile i have no issues, and everything works fine.

But if i try to decrypt file with 3rd party tools i get garbage.

Any ideas?

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Maybe some additional info needed? I'll gladly provide it, just tell me which... :

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Your info is vague to say the least.

How do you know your 3rd party program understands the algorithm used by _Crypt_EncryptFile()?


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If I had to guess I bet they're using some custom algorithm but say it's RC4.


_AdapterConnections()_AlwaysRun()_AppMon()_AppMonEx()_BinaryBin()_CheckMsgBox()_CmdLineRaw()_ContextMenu()_ConvertLHWebColor()/_ConvertSHWebColor()_DesktopDimensions()_DisplayPassword()_DotNet_Load()/_DotNet_Unload()_Fibonacci()_FileCompare()_FileCompareContents()_FileNameByHandle()_FilePrefix/SRE()_FindInFile()_GetBackgroundColor()/_SetBackgroundColor()_GetConrolID()_GetCtrlClass()_GetDirectoryFormat()_GetDriveMediaType()_GetFilename()/_GetFilenameExt()_GetHardwareID()_GetIP()_GetIP_Country()_GetOSLanguage()_GetSavedSource()_GetStringSize()_GetSystemPaths()_GetURLImage()_GIFImage()_GoogleWeather()_GUICtrlCreateGroup()_GUICtrlListBox_CreateArray()_GUICtrlListView_CreateArray()_GUICtrlListView_SaveCSV()_GUICtrlListView_SaveHTML()_GUICtrlListView_SaveTxt()_GUICtrlListView_SaveXML()_GUICtrlMenu_Recent()_GUICtrlMenu_SetItemImage()_GUICtrlTreeView_CreateArray()_GUIDisable()_GUIImageList_SetIconFromHandle()_GUIRegisterMsg()_GUISetIcon()_Icon_Clear()/_Icon_Set()_IdleTime()_InetGet()_InetGetGUI()_InetGetProgress()_IPDetails()_IsFileOlder()_IsGUID()_IsHex()_IsPalindrome()_IsRegKey()_IsStringRegExp()_IsSystemDrive()_IsUPX()_IsValidType()_IsWebColor()_Language()_Log()_MicrosoftInternetConnectivity()_MSDNDataType()_PathFull/GetRelative/Split()_PathSplitEx()_PrintFromArray()_ProgressSetMarquee()_ReDim()_RockPaperScissors()/_RockPaperScissorsLizardSpock()_ScrollingCredits_SelfDelete()_SelfRename()_SelfUpdate()_SendTo()_ShellAll()_ShellFile()_ShellFolder()_SingletonHWID()_SingletonPID()_Startup()_StringCompact()_StringIsValid()_StringRegExpMetaCharacters()_StringReplaceWholeWord()_StringStripChars()_Temperature()_TrialPeriod()_UKToUSDate()/_USToUKDate()_WinAPI_Create_CTL_CODE()_WinAPI_CreateGUID()_WMIDateStringToDate()/_DateToWMIDateString()Au3 script parsingAutoIt SearchAutoIt3 PortableAutoIt3WrapperToPragmaAutoItWinGetTitle()/AutoItWinSetTitle()CodingDirToHTML5FileInstallrFileReadLastChars()GeoIP databaseGUI - Only Close ButtonGUI ExamplesGUICtrlDeleteImage()GUICtrlGetBkColor()GUICtrlGetStyle()GUIEventsGUIGetBkColor()Int_Parse() & Int_TryParse()IsISBN()LockFile()Mapping CtrlIDsOOP in AutoItParseHeadersToSciTE()PasswordValidPasteBinPosts Per DayPreExpandProtect GlobalsQueue()Resource UpdateResourcesExSciTE JumpSettings INISHELLHOOKShunting-YardSignature CreatorStack()Stopwatch()StringAddLF()/StringStripLF()StringEOLToCRLF()VSCROLLWM_COPYDATAMore Examples...

Updated: 04/09/2015

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If I had to guess I bet they're using some custom algorithm but say it's RC4.

Maybe Crypt.au3 uses some custom algorithm, instead?

I see, that the simplest way to decrypt my file, is to write own decryptor, based on Crypt.au3 algorithm.

Anyway, thanks for help

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The Crypt functions use the built-in Windows encryption routines, there's nothing there that's custom.


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#7 ·  Posted (edited)

Maybe Crypt.au3 uses some custom algorithm, instead?

I see, that the simplest way to decrypt my file, is to write own decryptor, based on Crypt.au3 algorithm.

Anyway, thanks for help

Nope. As BrewManNH pointed out. My remark still remains the same. Edited by guinness

_AdapterConnections()_AlwaysRun()_AppMon()_AppMonEx()_BinaryBin()_CheckMsgBox()_CmdLineRaw()_ContextMenu()_ConvertLHWebColor()/_ConvertSHWebColor()_DesktopDimensions()_DisplayPassword()_DotNet_Load()/_DotNet_Unload()_Fibonacci()_FileCompare()_FileCompareContents()_FileNameByHandle()_FilePrefix/SRE()_FindInFile()_GetBackgroundColor()/_SetBackgroundColor()_GetConrolID()_GetCtrlClass()_GetDirectoryFormat()_GetDriveMediaType()_GetFilename()/_GetFilenameExt()_GetHardwareID()_GetIP()_GetIP_Country()_GetOSLanguage()_GetSavedSource()_GetStringSize()_GetSystemPaths()_GetURLImage()_GIFImage()_GoogleWeather()_GUICtrlCreateGroup()_GUICtrlListBox_CreateArray()_GUICtrlListView_CreateArray()_GUICtrlListView_SaveCSV()_GUICtrlListView_SaveHTML()_GUICtrlListView_SaveTxt()_GUICtrlListView_SaveXML()_GUICtrlMenu_Recent()_GUICtrlMenu_SetItemImage()_GUICtrlTreeView_CreateArray()_GUIDisable()_GUIImageList_SetIconFromHandle()_GUIRegisterMsg()_GUISetIcon()_Icon_Clear()/_Icon_Set()_IdleTime()_InetGet()_InetGetGUI()_InetGetProgress()_IPDetails()_IsFileOlder()_IsGUID()_IsHex()_IsPalindrome()_IsRegKey()_IsStringRegExp()_IsSystemDrive()_IsUPX()_IsValidType()_IsWebColor()_Language()_Log()_MicrosoftInternetConnectivity()_MSDNDataType()_PathFull/GetRelative/Split()_PathSplitEx()_PrintFromArray()_ProgressSetMarquee()_ReDim()_RockPaperScissors()/_RockPaperScissorsLizardSpock()_ScrollingCredits_SelfDelete()_SelfRename()_SelfUpdate()_SendTo()_ShellAll()_ShellFile()_ShellFolder()_SingletonHWID()_SingletonPID()_Startup()_StringCompact()_StringIsValid()_StringRegExpMetaCharacters()_StringReplaceWholeWord()_StringStripChars()_Temperature()_TrialPeriod()_UKToUSDate()/_USToUKDate()_WinAPI_Create_CTL_CODE()_WinAPI_CreateGUID()_WMIDateStringToDate()/_DateToWMIDateString()Au3 script parsingAutoIt SearchAutoIt3 PortableAutoIt3WrapperToPragmaAutoItWinGetTitle()/AutoItWinSetTitle()CodingDirToHTML5FileInstallrFileReadLastChars()GeoIP databaseGUI - Only Close ButtonGUI ExamplesGUICtrlDeleteImage()GUICtrlGetBkColor()GUICtrlGetStyle()GUIEventsGUIGetBkColor()Int_Parse() & Int_TryParse()IsISBN()LockFile()Mapping CtrlIDsOOP in AutoItParseHeadersToSciTE()PasswordValidPasteBinPosts Per DayPreExpandProtect GlobalsQueue()Resource UpdateResourcesExSciTE JumpSettings INISHELLHOOKShunting-YardSignature CreatorStack()Stopwatch()StringAddLF()/StringStripLF()StringEOLToCRLF()VSCROLLWM_COPYDATAMore Examples...

Updated: 04/09/2015

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