Results 1 to 4 of 4

Thread: Decrypting a text file to a string variable, possible?

  1. #1

    Thread Starter
    Hyperactive Member Krass's Avatar
    Join Date
    Aug 2000
    Location
    Montreal
    Posts
    489

    Decrypting a text file to a string variable, possible? (thread still opened!)

    I have a small question.

    Let me explain how my application works.
    My application connects to an ftp and downloads Hello.txt. Hello.txt is encrypted using the code on the following thread: http://forums.vb-world.net/showthrea...threadid=21091

    What I need to know is if there is a way to decrypt the text file, but in a variable or any other container of some sort? Because the content of the text file must remain unreadable to the user. Any idea?
    Chris

  2. #2
    Fanatic Member gwdash's Avatar
    Join Date
    Aug 2000
    Location
    Minnesota
    Posts
    666
    ok, why not decryt it to a new file, then read in the file, then delete it.

    [code]
    Private Declare Function CopyFile Lib "kernel32" Alias "CopyFileA" (ByVal lpExistingFileName As String, ByVal lpNewFileName As String, ByVal bFailIfExists As Long) As Long
    Private Declare Function GetTempFileName Lib "kernel32" Alias "GetTempFileNameA" (ByVal lpszPath As String, ByVal lpPrefixString As String, ByVal wUnique As Long, ByVal lpTempFileName As String) As Long

    Private Declare Function GetTempPath Lib "kernel32" Alias "GetTempPathA" (ByVal nBufferLength As Long, ByVal lpBuffer As String) As Long



    Private Function GetDecrypted() As String
    Dim MyTempPath As String
    Dim FileStuff As String
    MyTempPath = GetTemp
    CopyFile "a:\myfile.txt", MyTempPath, False
    DecryptFile MyTempPath, 44 'decrypt file

    Open MyTempPath For Input As #1 ' open it
    Do Until EOF(1)
    Input #1, temp 'read and append new data to variable
    FileStuff = FileStuff & temp
    Loop
    Close 1
    Kill MyTempPath ' delete file
    GetDecrypted = FileStuff 'return value
    End Function


    Private Sub Form_Load()

    End Sub

    Private Function GetTemp()


    ' Generate a temporary file (path)\api????.TMP, where (path)
    ' is Windows's temporary file directory and ???? is a randomly assigned unique value.
    ' Then display the name of the created file on the screen.
    Dim temppath As String ' receives name of temporary file path
    Dim tempfile As String ' receives name of temporary file
    Dim slength As Long ' receives length of string returned for the path
    Dim lastfour As Long ' receives hex value of the randomly assigned ????

    ' Get Windows's temporary file path
    temppath = Space(255) ' initialize the buffer to receive the path
    slength = GetTempPath(255, temppath) ' read the path name
    temppath = Left(temppath, slength) ' extract data from the variable

    ' Get a uniquely assigned random file
    tempfile = Space(255) ' initialize buffer to receive the filename
    lastfour = GetTempFileName(temppath, "dec", 0, tempfile) ' get a unique temporary file name
    ' (Note that the file is also created for you in this case.)
    tempfile = Left(tempfile, InStr(tempfile, vbNullChar) - 1) ' extract data from the variable
    GetTemp = tempfile
    End Function
    GWDASH
    [b]VB6, Perl, ASP, HTML, JavaScript, VBScript, SQL, C, C++, Linux , Java, PHP, MySQL, XML[b]

  3. #3

    Thread Starter
    Hyperactive Member Krass's Avatar
    Join Date
    Aug 2000
    Location
    Montreal
    Posts
    489
    Actually, there was no problem for me to download the file, decrypt it, use its content and then delete it. The thing is i'm afraid the content could be seen (let's say a cracker/hacker that REALLY want to read the content).

    I want to avoid this.. as a kind of security.
    Chris

  4. #4
    Fanatic Member gwdash's Avatar
    Join Date
    Aug 2000
    Location
    Minnesota
    Posts
    666
    then modify the decrypting algorithm not to write to a file, but to return the data

    Code Later
    GWDASH
    [b]VB6, Perl, ASP, HTML, JavaScript, VBScript, SQL, C, C++, Linux , Java, PHP, MySQL, XML[b]

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Click Here to Expand Forum to Full Width