I have created an updater for my application. When the application starts the user can launch an updater that will check for the latest version. Download it and copy the files to where the installation is.
Everything works fine.
However, I am looking for a more robust technique. And I have discovered it is better to hash the files on the web server with a hash algorithm and then when they have downloaded use the same hash algorithm to compare the hash values. If they are different either the files were corrupted when downloaded or some modified them without permission.
However, my problem is where do I store the hash values? I was thinking of hashing the files, and storing all the hash values for each file in a text file, and my updater will download that text file.
I am not sure if that is the best technique to use of not? Is this the normal and best way to do this?
I'm encrypting a file with AES using CryptoStream. I'm also creating a CRC32 hash of the original file data. Later I need to decrypt the file and create a CRC32 hash of the decrypted data, in order to check if the decrypted file is 100% the same as the original file.
This is a part of the encryption routine. I'm reading a file in chunks and writing them encrypted to a new file. At the same time I'm creating a CRC32 hash of the chunks of data, which will give me the CRC32 hash of the entire file in the end. This works fine.
vb.net '// Create the CryptoStream Dim Crypto_Stream As New CryptoStream(FS, crypto_transform, CryptoStreamMode.Write)
I have discovered that the .Net Hashing functions, MD5, SHA1, and SHA512 (all of them probably) do not allow us to create hashes of files greatedr than 2GB in size. If I use a function like the following:
How can I Implement Drupal 7's Hashing Algorithm into my software so that I can make a database query that allows the user to login? I know that they use SHA-256 bit and they use Base64 encoding and a salt generating algorithm...
I'm trying to teach myself arrays as I have not extensively worked them. So I thought of a basic program to hash the contents of an array and list the output of the array word next to the hash value of it.
I desperately need this VB.NET code converted to PHP.This is the Instructions I received:To test your encryption, encrypt the following word with these keys and check if you get the same result:
Text to encrypt: MyPassword Salt key: *&^%$#@! PBE Key: FWV70700[code].....
I have the following in C#: public static void StartAnimation(UIElement animatableElement, DependencyProperty dependencyProperty, double toValue, double animationDurationSeconds, EventHandler completedEvent)
I've been trying to figure out how to do this for some time now and keep coming up short, so I'm hoping to get some good suggestions.
I'm making an application that will allow the user to add some labels during runtime, edit their text, and then 'build' the designer that would output code for a scripting language.
The people using this app are creating the scripts using Notepad++ at the moment, but aren't developers in any way and would like an easier, point and click method.[code]...
i want to extend the integer class to a method that increments current integer value by 2. I create a console application and a second module which contains the extension method.
and everything works fine. The extension method module can be imported to any other project (Project-->add existing item --> select the vb file that contains the extension method module) and works fine too. But the code is accessible to other users. Is there a method to convert the extension method module to a dll and adding it to other projects as a reference. I tried to do it with creating a class project and pasting the code of the extension method module and compile the dll and then added it as reference to another project and imported the class with the keyword imports, but it didn't work.
I've been trying to create a FCS16 (Frame-Check-Sequence) hashing algorithm, but so far the only explanation I've found is this [URL]and I'm having trouble writing the code.
I have some files in vb.net that have "Option Strict Off" to allow for bad programming. When I convert to c# I use "dynamic" until I come back and fix problems, and this works in all cases But now I have this code:
Public Class ContractResults 'Big class definition Public Shared Sub CleanCache()
[code].....
And in a file with Option Strict Off:
Public Sub VerifyResults(result as Object) 'Here, result is normally ContractResults 'first it check for that then call this: result.CleanCache() End Sub
In c# I use "dynamic", but a runtime error pops up when I call "static" method with dynamic reference. In vb.net, I can called "shared" sub from instance, but in c# this is not allowed
Exception: "Microsoft.CSharp.RuntimeBinder.RuntimeBinderException" "Member 'ContractTypes.ContractResults.CleanCache()' cannot be accessed with an instance reference; qualify it with a type name instead"
It seems I must convert code to use actual type, but then this means much rewriting of more parts. Is anyone able to show another way?I want to make sure you do not think I can use (result as ContractResults).CleanCache();Because all types that may be passed in have "CleanCache()" method, but do not inherits from anything the same other than "Object". There are many types (30!) that have this "static" method and so that is why it uses Option Strict Off?
Consider a MyForm class that contains a shadowed implementation of Show(). It also contains a CreateForm() method, which accepts an instance of the form and calls the shadowed sub:
I want to perform two hashing operations concurrently on a single file, without reading the file twice. Is there some way to share the FileStream between two synchronized hashing threads? For example:
Dim Stream As New IO.FileStream("...", IO.FileMode.Open) Dim HashA, HashB As Byte() Dim A = New System.Threading.Thread(Sub()
[code]....
Maybe some way of caching a stream? Trouble is, I don't want the entire file in memory at once (it could be many gigabytes in size) and I don't want the file read more than once, due to speed issues. I want the file cached only sufficiently to ensure that both threads can work.For example, suppose at some point in time, thread A had read 100k of the file, but thread B had only read 20k of the file. The portion of the file between 20k and 100k should be cached; but then progressively forgotten as thread B catches up. Then again, if thread B is too slow, we might still end up with hundreds of megabytes being cached.Maybe thread A should be made to wait while thread B catches up. Maybe the ReadByte() function of the stream should block for a while if one of the threads is too far behind?
explain what is the difference between IsDbnull() method and convert.isDbNull(). Can you explain how do we implement both these methods with the of examples
I have a large problem with inheritance in vb.net. The problem is the following:
I have 2 forms => frmBase and frmChild
In frmBase i want to create a method Called StartWorking() and i want frmChild to inherit this method.
But here is the tricky thing: when frmChild.StartWorking is called i would like the following => without calling MyBase.StartWorking()
I want frmBase.StartWorking() to be executed first and after a test in frmBase.StartWorking if blnValue is true then frmChild.StartWorking has to be activated. if blnValue is false that frmChild.StartWorking cannot be activated.
I have nine pictures that I need to animate -I need to use the ToString method and a counter to concatenate a file name into a string variable from the Image.FromFile method. Once the counter reaches its maximum value, and the last picture is displayed, the counter should be reset to zero or one depending on how the first image file has been name. Also a static counter variable should be incremented in the time routine. what I have so far -- I know what I have to do; however, I just do not know how to code this properly.. Right now I have this going thru a button procedure but it needs to go through a timer.
When I am loading an Assembly dynamically, then calling a method from it, I appear to be getting the method from Assembly executing before the code in the method that is calling it.It does not appear to be executing in a Serial manner as I would expect. Can anyone shine some light on why this might be happening. Below is some code to illustrate what I am seeing, the code from the some.dll assembly calls a method named PerformLookup. For testing I put a similar MessageBox type output with "PerformLookup Time: " as the text. What I end up seeing is:
First: "PerformLookup Time: 40:842" Second: "initIndex Time: 45:873" Imports System
Why does my the declaration of my string in the code result in the following error? Is there a workaround?
Code:
<script runat="server"> Protected Sub form1_Load(sender As Object, e As System.EventArgs) Dim x As String = "</script>"
[code]....
Error: Statement cannot appear within a method body. End of method assumed.
Note: The following page did not fix my issue and instead resulted in the string </script> being output in my page. ( VB.NET hates </script> tag in string literal )