.net - Rijndael Encryption Code Is Not Working For Large File?
Oct 1, 2011
I use the following Rijndael code to do encryption without fail for many times. But why it can not encrypt an ISO file with 4.2 GB? In fact my computer has 16GB memory and it should not be a memory problem. I use Windows 7 Ultimate. The code is compiled as winform (.Net 4) using Visual Studio 2010 (a VB.NET project).
I have checked that the ISO file is OK and can be mounted as virtual drive and even can be burnt to DVD rom. So it is not the ISO file problem.My question: Why the following code cannot encrypt an ISO file with size of 4.2GB? Is that caused by the limitation of Windows/.NET 4 implementation?
[Code]...
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Sep 29, 2011
I'm creating a Rijndael file encryption application. I will using a unique IV for each file encryption.
My question: Where is the proper place to embed the IV info?
My initial thought is to append it at the end of the file's content. Is that a good choice?
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Sep 12, 2011
At first i thought it was the padding since mcrypt uses zero padding but i changed the php to use PKCS7 and get the same exact results.I think it has something to do with the padding in the php.Test output from .Net:
Key: d88f92e4fa27f6d45b49446c7fc76976
Text: Testing123
Encrypted: /DMkj7BL9Eu2LMxKhdGT+A==[code]......
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Feb 11, 2012
I am using a slightly modified version of this code. to create a mission critical application. That files that will be encrypted are very important. This has to be done from scratch because there are some other things that has to be done along with this. How secure is this? Its impossible to crack this encryption right? [Code]
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Sep 3, 2011
My current approach of using Rijndael is to use a pair of static Key and Iv for all encryption operations (I mean I use this pair of Key and Iv for all protected files in my computer).
I heard that IV must be unique for each Rijndael encryption. Is that true? What is the problem (if any) for my current approach of using single static Key and Iv pair?
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Nov 13, 2010
I want it to do is that you input a string, then you select an algorithm (Theres only going to be one RijnDael) then you input a key, then the Initialization Vector comes from "txtIV.text" then you select the key bytes and the block bytes from the numeric up/down, then you either encrypt or decrypt.
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Feb 28, 2011
I'm having trouble writing the code to encrypt a file->networkstream->Decrypt the file.. I've tried several ways, but I keep failing....
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Apr 29, 2011
I am uploading a file from a C# application to an ASP.Net website, both written by me so I have access to the code.But, it is working for a text file (1KB) but not for a MOV file (77MB).
In both cases, I am using UploadProgressChanged to get the progress. The TXT file goes to 100% while the MOV file goes only till 50%. When done, I only find the TXT file saved on the server but not the MOV file.
Why is this happening? How can I get it to work?
[Code]...
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Dec 16, 2009
I've attempted using code snippets as a test to encrypt a string, save it to a file & the reload it back, decrypting it. I consistently get a "Padding is invalid and cannot be removed." error on decrypting the string.
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Aug 19, 2009
when my.settings.datastorage has nothing in it, this works fine. but after i go through this twice, it gives me an error
[Code]...
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Oct 15, 2009
I have spent quite a while trying to solve this problem.I would like to be able to decrypt a file using an old password, then encrypt the file with a new password in memory. I could easily write the unencrypted file to disk then encrypt the file with a new password, BUT I was trying to keep the unencrypted file from being written to disk. Could someone point me in the right direction?
Private Function ReEncryptFile(ByVal PathToFile As String, ByVal OldPassword As String, ByVal NewPassword As String) As Boolean End Function I've been using a cryptostream to decrypt the file, but I cant seem to figure a way to encrypt the crytostream afterwards (or convert it to a memorystream and (re)encrypt the memorystream)
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Feb 18, 2012
[Code]...
The loop will run about 3 times then overflow. I guess no matter what u do xor will result in Byte,Integer or Long. CDec(Key) will not work I need a way to bypass this so i can Xor large numbers.
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Oct 25, 2010
How can I calculate 2^ 3333 in vb.net it calculates up to 2^ 60 it says infinite for this calculation. Is tehre any way to work with really large numbers?
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Apr 28, 2011
For example, to calculate this:(22 ^ 29) Mod 57Supposedly there is a way to get around overflows and do these calculations, but I can't find much online. Now, the person who said this was doing VBA in Excel and said that there was about 4 lines of code which could handle the overflow so it wouldn't happen.
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Jul 6, 2010
I am using Virtual Basic with ASP.NET in Visual Studio 2008. I am using Webmethod to communicate from/to the server with the client. Data can be queried and returned in small amount, but when I try get a relatively large amount of data, it's returning me a Server 500 error. My data is 226561 character long, so it's not that large, but it's relatively larger than my other working testing set, which are about 10k character long.
JavaScript:
PageMethods.my_func("context", success);
function success(result, userContext, methodName) {
[code].....
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Dec 9, 2011
I am using Virtual Basic with ASP.NET in Visual Studio 2008. I am using Webmethod to communicate from/to the server with the client. Data can be queried and returned in small amount, but when I try get a relatively large amount of data, it's returning me a Server 500 error. My data is 226561 character long, so it's not that large, but it's relatively larger than my other working testing set, which are about 10k character long.
JavaScript:
PageMethods.my_func("context", success);
function success(result, userContext, methodName) {
[code]....
Is there anything I can change to increase WebMethod returned string length limit? Is there even a length limit or is it some other problem I could not see?
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Apr 25, 2011
I recently wrote a program that collects information from the network can displays it in a DGV for the user to see. I tested this on networks where I would end up with several thousand items brought back and all worked fine, very little memory increase and once the search had finished the memory usage went back to pretty much what it was before the search, so I assume I have no major memory leaks that I should be concerned about (I'm careful to always dispose of things and clear large variables where possible).
However, a new company has now started using my application and they have several hundred thousand items that my program will find. They reported that they leave the program running its search for a few hours and most of the time it crashes with an Out Of Memory exception. Now I did have my app do some caching of certain information to avoid querying the network more than was necessary so I thought well maybe this is what is causing it but I added an option to turn that off and they say it still happens. So the only thing I can see it being is simply the amount of data that the program is finding and having to store in memory.once my application has gathered information about the items it stores them in a List(Of MyItemClass) and then when the search is complete the items are added to the DGV. So I'm thinking maybe its just the size of this List(Of MyItemClass) that is simply getting too large. Bear in mind that each instance of MyItemClass in this List can have quite a lot of information in it as it has several properties that are List(Of String) that may contain a few thousand strings in some scenarios.How do you deal with such large amounts of data without running out of memory?I'm assuming the only option I have got is to 'page' some of the data to a temporary file on disk once I get over a certain number of items in the List(Of MyItemClass)?
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Mar 23, 2012
I have another project that I have to submit it in a few days my project is about bifid cipher..I already make a code work but the thinks that I frustrated is to add like a space,enter,comma,or other symbol inside my code [code]at my code all the space will be disappear and if a enter in plaintext it will combine..already try to use index to find a space but it only works for the first space..
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Dec 22, 2010
how to put my vb login code into my html code so that the login encryption works on my webpage.
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Feb 22, 2012
I'm reading a file and then closing it with the following code, but my problem is later when I start a batch process it says the file is still in use. Am I doing something wrong in closing it? The process was working fine prior to my adding this code to read the file.
[code]...
This rexx exec is trying to write to the file that I read from in the prior step before creating a PowerPoint presentation, but fails becuase of the lock.I'm at a loss. I should qualify and say the process actually starts, but fails in the rexxexec after it starts, it isn't failing on the process start the rexx exec issues a message that it can't write to the file becuase it is in use.
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Sep 3, 2009
I found on msdn samples and modified (add Thread.GetDomaind.UnhandledException)
<SecurityPermission(SecurityAction.Demand, Flags:=SecurityPermissionFlag.ControlAppDomain)> _
Public Sub Main()
' Add the event handler for handling UI thread exceptions to the event.[code].....
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Jun 15, 2012
ive been trying to use System.Security.Cryptography to encrypt and decrypt a file but its not working for me
this code
Private Sub EncryptFile(ByVal sInputFilename As String, ByVal sOutputFilename As String, ByVal sKey As String)
Dim fsInput As New FileStream(sInputFilename, FileMode.Open, FileAccess.Read)
Dim fsEncrypted As New FileStream(sOutputFilename, FileMode.Create, FileAccess.Write)
Dim DES As New DESCryptoServiceProvider()
[code]....
called with
DecryptFile(OpenFileDialog1.FileName, SaveFileDialog1.FileName, "12345678")[/CODE]
outputs a file that is almost 2x as large as the source file that was encrypted.
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Apr 13, 2012
I would like to read the contents of an existing Outlook 2007 PST file by VB.Net. I find already the file and record structure, this is not a problem. But I have a problem with the compressible encryption how is used. Now I have read that this encryption is based on a simple byte-substitution cipher with a fixed substitution table. But unfortunately I can't find this table. Maybe someone can help me where to find this table or where I to find all the necessary information about compressible encryption.
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Aug 4, 2009
Imports System
Imports System.IO
Imports System.Security
Imports System.Security.Cryptography
[code]....
The above code is used by me to encrypt .avi files and it worked very well but the problem is that if the size of my video file is greater than 200 mb memory overflows probably as the code copy the whole input file into ram and then process it hence it put limitation of hardware,is there any better way to do it so that files > 200 mb could me encrypted in PCs with 1gb ram?
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Jul 13, 2011
I'm looking for advice/ideas in regards to ongoing file encryption.I have an event that fires frequently that contains small amounts of data passed through the eventargs.This data is then written out to disk (currently unencrypted).I need to encrypt this data (which, I can do).My attempt in the first five minutes was unencrypting the file, appending the data and reencrypting the file.This obviously works, but is pretty inefficient and not going to be my solution since the file could grow rather large and the resources to unecrypt/ encrypt grow larger as the file grows larger.My next thought was to encrypt each set of data as it's written out and have some kind of marker in the file to denote where to split so I could unencrypt each chunk to reproduce the original file.I'm leaning towards this approach now (though by encrypting small chunks of data multiple times, the file size will be considerably larger.As an example, if I encrypt each letter of the alphabet the file is approx 8 times larger than if I encrypted a string with all of the letters of the alphabet in this case each files decrypted content would be identitcal).
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Jun 16, 2011
1. How much load or data size our custom encryption/decryption algorithm can handle? E.g. what's the limit of file size that normal encryption/decryption algorithm supports.
2. What's the best way to use encryption while file transfer via internet?
3. Where and when encryption and decryption has to apply while uploading and downloading content from internet(Hosting on client or server machines)?
4. What type of algorithms suites for above approaches?
5. How much time it takes to encrypt / decrypt data for 10 MB, 100 MB, 1 GB etc
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Jun 10, 2010
Dim sw
As StreamWriter
Dim flagX
As
Boolean
[code]....
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Apr 12, 2010
I have the following code to generate combinations of string for a small list and would like to adapt this for a large list of over 300 string words.Can anyone suggest how to alter this code or to use a different method
[Code]...
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Jul 12, 2011
I am trying to make a key that will be used in file encryption/decryption for my application. However, there is no user data involved with this application (As i would usually use the user's password to generate the encryption key), so i have to turn to another method.
I am thinking that maybe it is possible to generate a completely random key the first time the program runs, then save this key inside the program so that it is inaccessible by the user. The user will not be shown this key, but the key MUST be randomly generated for each application, and it also must stay constant once it is created.
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Jun 21, 2011
I have set up a method in vb.net and in xcode for encrypting a string using as far as i can tell the same parameters for an AES encryption.I've looked all over the place but cannot find information on whether they use the same encryption algorithm and settings.
this is the vb.net code:
Dim encryptAES As New AesCryptoServiceProvider()
Dim encoding As New UTF8Encoding()
Dim encryptor As ICryptoTransform
encryptAES.Key = encoding.GetBytes("12345678901234567890123456789032")
encryptAES.IV = encoding.GetBytes("1234567890123416")
encryptAES.Mode = CipherMode.CBC
[Code]...
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