So I can encrypt small files using Des Encryption, but whenever I try encrypting large files, The program's memory usage skyrockets! Would anybody be able to get me some code that will let me encrypt large files (It doesn't have to be Des, but I need to be able to support any length password).
View 1 Replies
I am working on a application that stores videos, images and files. I would like to give the user the possibility to encrypt them. I am tying to use AES to encrypt them but the problem is that the decryption takes to long.I was hoping that the loading time from the hard disk of the encrypted file was far longer than the process of decryption of an image for example but i was wrong
So if i try to 1) load the image 2)decrypt it and 3)load it in a image control it takes 15 times more time that loading the original file not encrypted
I am new to VB.Net, but I can tell you so far I love programming. That said, I'm building a tool basically to parse and display simple plain text log files. I'm hitting one stumbling block that really has me frustrated.
Other tools are able to load huge log files (500MB even) in a number of seconds. My tool, basically hangs loading a file that is maybe 5MB.
I'm using the MyString = StreamReader.ReadToEnd to read the contents into a string, and then RichTextBox1.Text = MyString to display the contents. That said, I really want to display the contents in a datagrid, but there has to be a better way of doing this?
How can I get my application to load larger files and display them faster? What am I doing wrong?
I wrote a program to download and play AVI files the files are large in size and long time wise. I have the files playing as they are being downloaded but i can't see how long the file is or seek reliably. i was reading that the AVI headers are in the last 512kb of the AVI file *why would't they put it at the start* lol so my question is is there a way to download the last 512Kb of the file i'm downloading. i have the Bytes Read and Length of the file while its downlaoding i'm just not sure where to go from there, or how to do it atleast. If i had the length in time of the Avi file i could set the trackbar to be able to seek properly. or if someone has an idea how i could get the time of the video by using fps and some math i could prob do it that way too but idk how i would tell how i can find how many kb are in the fps i'm sure it changes so think that way is't going to be reliable. how to get the last 512kb would be the best option not sure if it can be done even.
View 4 Repliesim working on making a password saving program but my problem is that i don't know how to encrypt the files.
View 11 Repliesi am trying to make a small program to encrypt files using AES, and then have the password from the AES encrypted using RSA for its use of public keys. i've got the AES part working fine and i found a good RSA tutorial here url....but after i encrypt the AES password (which is saved in a .txt file) using RSA, then i try to decrypt it again, it comes out as an empty .txt file!
View 4 RepliesI'm designing a program to encrypt and decrypt files using TripleDes Encryption algorithms but am having issues decrypting an image file. The file encrypts in the correct manner, but when I go to decrypt the file and open as an image I get an error message. One example is when trying to open the file in paint a message appears stating 'c:New FolderDecrypted.jpg Paint cannot read this file. This is not a valid bitmap file, or its format is not currently supported. My coding for the form is shown below:
"Imports System.Windows.Forms
Imports System.Security.Cryptography
Imports System.Security
[Code]....
I use this code to create dump files of my database. Now what I want, if possible, is to encrypt it so that when it is viewed in notepad or anything similar, average users cannot read it.
Call isDirectoryExist()
Call createDbBackupName()
Dim myProcess As Process = New Process
Dim strUser As String = "superadmin"
[Code] .....
Of course, if it encrypted, it has to be decrypted before querying the dump file. I have no idea what encryption I can do in vb.net and mysql
I modified my first code
Process.Start("C:/MySQL/bin/mysqldump.exe", " --host=localhost --user='" & strUser & "' --password=1234 """ & strDbName & """ -r """ & strPath & newDBName & """, --cipher /e /a '" & newDBName & "' ")
But the output file contains nothing whatsoever.
Lets get down to it, Basically, I'm making a kind of "Anti-Hack" for a project I'm working on.The basis of the "Anti-Hack" is the check processes for names of known Memory Editors, For example, one memory editor I am scanning for is Cheat Engine.exe, I am using this code to scan for it, then I use the result to activate a different piece of code.
If Process.GetProcessesByName("Cheat Engine").Length = 0 The
'It's OK
Else
<Removed for obvious reasons>
End If
Basically, I don't want my code to look like a library of If statements when the only thing I am changing is the process name, what I want to do, is have an encrypted .dat file with an array or list of known tools. I want to then go through the array/list and keep checking for instances of them running.I know nothing of how to encrypt/decrypt .dat files through VB. (I'm not an expert at it atm )I am open to other ways (Easier ways) of doing this, like a Class with a list of names etc.
**NOTE** I would rather it be a separate file as the program features an Auto-Update feature, so it will be easier to update the list.
**IMPORTANT**Also, I would like to know how to hide my process, so it cant simply be ended, It may sound suspicious but people will be able to just close it and start hacking T_T, Unless there is another way, I would appreciate it (Like making it so it cant be ended etc.)**IMPORTANT.
I'm attempting to create a little library to encrypt and decrypt Files with AES. There are loads of examples of how to do this on the internet so coding is not a problem. There are however a few questions regarding cryptography and AES in general.
#1 Does the IV need to be kept a secret like the key ?
#2 Can I just hash a string with SHA512 to make a key for AES ? or do I need to use PasswordDeriveBytes ?
#3 In the case of me using PasswordDeriveBytes Do I need to keep the salt a secret ?(or do I need to keep it at all)
#4 Can I generate the IV from the same password that the Key is derived from ?(if so How ?)
How do you recommend I copy large files over the LAN (>20GB)Currently I am using File.Copy.Another question I have is how can I implement this class to be self contained, meaning that it would report progress to the object that called it? or do I have to define a delegate in the calling object?
Code:
Public Class cCopier
Private Delegate Function CopyProgressRoutine(ByVal totalFileSize As Int64, ByVal totalBytesTransferred As Int64, ByVal streamSize As Int64, ByVal streamBytesTransferred As Int64, ByVal dwStreamNumber As Int32, ByVal dwCallbackReason As Int32, ByVal hSourceFile As Int32, ByVal hDestinationFile As Int32, ByVal lpData As Int32) As Int32
[code].....
The underlying connection was closed: An unexpected error occurred on a receive.If I look on te FTP server I can see that the file has been uploaded entirely which led me to believe that the control channel was timing out. I have tried modifying the timeout on the FTP server as well as the ReadWriteTimeout in my code to no avail.Here is my code...
Dim ftprequest As System.Net.FtpWebRequest = DirectCast(System.Net.WebRequest.Create(destination), System.Net.FtpWebRequest)
ftprequest.Credentials = New System.Net.NetworkCredential(username, password)
[code].....
I am opening a large PDF file using the following
Process.Start(Application.StartupPath & "PREVI.pdf")
I have two questions:
1) Is there a way to go directly to a page number?
2) Can I write a code to have the table of contents show up on the left side of the document so users can click on to go to different sections of the document, not sure if this needs to be done while creating the PDF or if we can do it by code.
If you were to upload a project to any site but are concerned about the large file size, what are the only files you need to zip up for your project to work for either VB 2008 or VB 2010? So far I know you don't need the exe's, the pdbs, and xml files.
View 5 RepliesWhich is the most performant way to read a large csv file in .NET? Using FileStream? or another class
View 4 RepliesDoes anyone know what the best way to split up large files in VB.NET? These files can be in excess of 10GB. I have found ways of doing it by googling all day! most of the solutions I have found almost work. But what I really want to know is what is the most efficient way to do this?
View 1 RepliesI have trying to upload some large files using FTP. Here is the code I am using below.
Private Sub UploadFTP()
' Open file.txt with the Using statement.
Using r As StreamReader = New StreamReader("list.txt")[code]....
I basically loop the above to upload all the files in a specific directory. This works fine with small text files,but when I try uploading a large 30+- mb file it gives me an error.
Quote: The underlying connection was closed: An unexpected error occurred on a receive.
On
cls_stream.Close()
I understand this is caused by .Net not communicating with the server properly? I tried searching all morning to only get confused by all the different methods.
I have created an vb.net windows application. In the application i have 2 xml files (e.g., Pre.xml & Post.xml) & the 2 files are same structure.
My requirement is compare the pre & post xml files and get the differences between xml files. Like what are all the newly added nodes, removed nodes and modified nodes as well.
I tried with XmlDiffPatch.Dll, it is working for small size xml files, but in my case xml file size should be upto 100+ mb.
I am using this code to write files
Try
Dim ObjWS As New localhost.Service
'ObjWS.AssigningDataToTemplate(1550, arrValues)
[Code]....
Here i got proble to send a large size of file like 500 mb file etc
Just a doubt: if I have large amount of image files for my app, is it ok to store them in the resource file ?
Will those files be saved in a single resource file ? Will that cause any problem to the performance of my app ? When I try to access a image file from the resource using code, will it load that file only into the memory or the entire image contents from the resource file ?
I am working on a program for a customer and am working in VB2010 in VB language. I have two rather large files that contain data. File #1 is over 300,000 lines of data. File #2 is over 100,000 lines. The files are CSV text files. On a User Form, there are two values, "StartTime" and "StopTime". This is the process I am doing:
1. Read both files into ArrayLists
2. Get item #1 of ArrayList #1 (we'll call this "A")
3. Get item #1 of ArrayList #2 (we'll call this "B")
[code]....
I am writing a small tool that identifies digital scielence in non compressed PCM WAV files. Its purpose will be to scan files approximately 1 hour long, containing mostly scilence and spltting the periods of non scilence into files and discarding any digital silence which is encoded as null bytes.I am wondering what the most efficient way of scanning the files is. I am able to derive the number of bytes for each second from the file header (in my case 16000) so am considering reading into a buffer of this size then scanning byte for byte, if I identify a non-null byte I will start siphoning the data off to another file.My issue is with scanning large expanses of digital silence which could be many megabytes of data which would require examining each byte to determine wether or not its digital silence. Surely there is a more efficient way of skipping them as I am not interested in them.
View 7 RepliesMy problem is I have very large text files (approx 2GBs+).They have records in them based in one per line.Each line is not the same length and the data can be different lengths all the time.I am currently reading the file line by line, then splitting the data by common characters in the records. To process the full file it currently takes 3hours. This is way too slow for its purpose.
View 7 RepliesI have a series of large files (4GB) that when I delete takes a very long time. This only occurs on a USB drive that I have attached to my PC. If I do the same thing on the internal drive the files delete quickly. It is as if the files are being overwritten before being deleted. I am looking for some guidance or other approaches.
View 5 RepliesI have two large text files (about 1.8 GB each encoded in UTF-8). And I want to check if the content of both files are 100% same. If there is single character difference then it is considered not same, i.e. both files are different. How do I do that? So my question is: How to check if 2 large text files content are 100% same?
[Code]...
I have a large file (2.7GB). I need to split it into smaller files. How to split a large file into smaller files using VB.NET 2003? Cannot use LINQ and the resources (cpu and memory) on operating environment are very limited (it is a shared hosting environment).
View 1 Replies[Code] each file is about 30 kilobytes in size, and they contain raw hardware statistical information in a comma-deliminted format. I want to do the following with these files as my end-result.
NEWFILE.CVS contains the contents in this format:
metric_group_001 metric_group_002 metric_group_003 metric_group_004 etc.
I don't want APPEND, I want to concatenate the contents of these files into one large master file. I am able to do this MANUALLY, but I need to have a DYNAMIC method of doing this because of the number of files will change depending on the test we are doing with the hardware. This is the code I am using to do this process manually and it does work, but I need a DYNAMIC method in place. [Code]
I am using zipforge.net to archive files in a small backup program I am creating. Everything works fine however if I try to archive a large number of files the process of zipping them gets slower the further along in the job it gets.
Example: I have a directory that contains a little over 100,000 files in it. Each file is only about 200k of text. When I use the zipforge zip class it starts zip'ing very quickly but as it gets about 40% of the way through the directory it starts to slow down... at about 60% its working at a snails pace.
Memory usage for my solution also goes up proportionate to the archive file size as it grows. Currently it takes around 26hours to backup this directory which only contains 4 gigs worth of information.
If I use a program like winzip I can zip the folder in less than an hour. I am thinking there has to be a way to write to the end of the zip file without having to open it every time or without keeping it open. My backup software scans the specified folder and writes each file path and name into a text file. Then it reads the text file line by line and passes the path + file info to the zipforge addfile().
I am trying to upload 2 large files to a ftp server by uploading as one file to a location. I have it working if the files are small but it crashes with large files.
For i As Integer = 0 To filelist.Count() - 1
Dim fRequest As FtpWebRequest = WebRequest.Create(ftpPath & "/Reports/" & filelist.Item(i))
fRequest.Credentials = New NetworkCredential(username, psswd)
[code]....
I'm tryng to read an excel sheet that has more than 255 cell. I'm using the following code:
Dim MyConnection As System.Data.OleDb.OleDbConnection
Dim MyDataSet As New System.Data.DataSet
Dim connectionString As String = ConfigurationManager.ConnectionStrings("PCOConnectionString2").ConnectionString
[Code].....
this code throws me an error that indicates me that there are too many rows to read. I found, seaching through forums, that it can't be more that 255 cells on the sheet i'm reading.
How can i read this sheet that has over 500 cells?
