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?
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?
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Im using Rijndael (as AES algorithm) for encrypting. I encrypt the values (objects properties) and serialize the object to xml an dsend the xml to the receiver via a web service. I want to pass along the encrypted symmetric key that I used to encrypt the data. But what key should I pass along?
My decryption algorithm looks like this (vb.net):
CODE:
If I want to decrypt the encrypted string I have to use both key and IV, but I think I have to pass along only a key value. Do I have to do this another way or what should I pass along? My specification says that the values have to be encrypted using AES and a 128 bits key.
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]......
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]
View 2 RepliesMy 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?
How would I be able to use my own Encryption Algorithm in my program such as encrypting text. I havn't been able to figure this out.
View 1 RepliesI 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.
View 1 Repliesi'm using the following algorithm to encrypt and decrypt a string in VB.NET and wanted to do that same method in Android also.
Encryption:
Private Function decryptStr(ByVal key As String, ByVal enc As String) As String
Try
DES.Key = Hash.ComputeHash(System.Text.ASCIIEncoding.ASCII.GetBytes(key))
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I am not sending any sensitive or security information in the query string. I am currently using Base64Encoding along with MD5 Hash. I want to shorten my url as far as possible.
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VS 2010 [RESOLVED] Proper location for Global Constant?
View 1 RepliesWrite a program that requests a name fomr the user and insert the name into the list in its proper location, if the name is already in the list, the name should not be inserted. --do not use any arrays or LINQ use only streamreader/streamwriter.What i've got is this...it will add the name but not in the "proper location". if i could use an array i'd just reorder the array and then write to file, but...
Imports System.IO
Public Class Project_3a_p398
'Purpose: A program that requests a name from the user
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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.
View 3 RepliesI 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)
I am making a program to organize grainbins in seperate yards.In this program, the grainbins need to be moved around and thier position to be saved when the program is closed. I also need to save information such as backcolour and text.I am specifically referring to GroupBoxes, OvalShapes, Textboxes, Labels, and ComboBoxes.
View 2 RepliesI am using VB2005 and trying to put an application together.What it needs to do is retrieve information from a binary file, possibly alter that information, and put it back into a new file.The file is a .wav file with data appened to the end. There is an additional section at the end of the .wav file which stores xml data.I have found that if I open this in a hex editor and make a 1:1 swap on any of the bytes that the application that the file is for can still read the XML.If I tried to add or remove characters from the XML then it would not read. I located a header byte and incremented it to resolve this.
This worked as an excellent bandage to do conversions where the data always needed to be changed to the same thing.What I have been asked to do is build logic that allows for different things to happen depending upon what data is contained within the file.The method that I am currently trying to impliment is:
Read through the file with a system.io.binaryreader
Searche for a bytestream that will signal data is coming
For example:
If System.IO.File.Exists("C: est estread.wav") Then
Dim findit() As Integer = New Integer() {&H3C, &H55, &H73, &H72, &H44, &H65, &H66, &H30, &H31, &H30}
Dim i As Integer[code].....
And then extract all the data till the end of element marker "<" It seemed like there should be a better way and I was looking for some insight. If I proceed with this method, I will have to read the file one time to gather the information and then a second time to write it all out with the header modified for length.This is my first experiene with working with binary files in this way.Also,I've been experiementing with building a string and slapping it back in at the end using the binarywriter.write(string) method.I noticed that it was putting in header characters before the string.These seem to change if I change the length of the string.At one point it was d0 07. Later it became e7 07. Does anyone know of a way to prevent this header from being inserted?
I tried a for each loop to grab all of the characters from the string, convert them to a byte array and deposit the byte array into the file, but the header remained the same. When I write the byte array generated from a system.io.binaryreader I do not get this header.
I'm having trouble writing the code to encrypt a file->networkstream->Decrypt the file.. I've tried several ways, but I keep failing....
View 1 RepliesI need to encrypt vbs file using a cryptographic algorithm. I read about converting it into vbe file, but is there any other way to do it?
View 1 RepliesI am trying to implement an Algorithm called "Diamond-Square Algorithm" I am having trouble ending it so that it retiurns the required result. So far I have the folloiwng.
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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()
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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.
What is the proper way to do a file.copy from source to destination in case there is already a file present in the source so that it does not give an error.
View 2 RepliesI know I can MD5 hash a file, but how do I go about using the SHA256 algorithm?
View 6 RepliesI have a file (Microsoft.PhotoToolboxFoundation.ToolboxPolicy.xml) which is read by the following code:
p = (New
MetadataPolicyManager()).loadPolicy("Microsoft.PhotoToolboxFoundation.ToolboxPolicy.xml").
Is there a way to embed the file into the .dll? Can I add the file as a resource or something similar and if so how would I reference it?
I am concerned that this code is copying bytes into a temporary buffer before writing directly to file.
I feel like there should be some method of copying bytes directly from the tail end of the main buffer directly to file.'this code copies all bytes starting at integer index from the main buffer into a new file: ga.exe
'declare temporary buffer
Dim EXEBytes(bytes.Count - index) As Byte
'copy subset of bytes over, starting at index
System.Buffer.BlockCopy(bytes, index, EXEBytes, 0, bytes.Count - index)
'write bytes from temporary array into file
File.WriteAllBytes(Server.MapPath("/BIN/ga.exe"), EXEBytes)
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.
View 7 RepliesImports System
Imports System.IO
Imports System.Security
Imports System.Security.Cryptography
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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?
I know that is strange situation, but I need to embed an EXE file (or the assembly code) into my project, so it can be started only by the application (it can't create the EXE in the filesystem and start it)...
Is it possible? Edit:It's not a .NET EXE. Anyway I added the Test.exe file as a resource to my project and I did this
Dim exestr As Stream = Nothing
Dim a As Assembly = Assembly.GetExecutingAssembly
exestr = a.GetManifestResourceStream("Test.exe")
I want to embed a exe file in my program, so that, it extracts it when the form is loaded and when the form is closed the exe file is automatically deleted. I have added that exe file in my resources but I can't call it in the FileCopy command.
View 5 RepliesI have some PDF files that my application generates and stores on my machine. Now each file has a persons name and address string related to it in a database. E.g.
Filename | FirstName | Email
The files can be selected within the application UI and emailed out. Now I don't want to have to hit the database each time since there are alot of files. So , how embed the two strings FirstName and Email into the file itself, so when I load it into a FileInfo object there is someway to access the extra data.
I have a db, and one of the columns in my db is an attachment column. It stores the link to a pdf document. I want the user to be able to browse through folders and select the proper pdf file. And when the user finally hits the submit button on the form my algorithm should put the necessary link into my db. I'm just not sure how to do this with regard to VB searching and finding the file, and then using my SQL statement to insert the attachment into my db.
Here is my code so far.
Private Sub SearchFile_Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SearchFile_Button.Click
Dim saveFileDialog1 As New SaveFileDialog()
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