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'm working on software which encrypts/decrypts files. I would like to be able to guess the length of the data after the encryption but I can't use CryptoStream.Length (It throws a NotSupportedException).
I am starting to use cryptostream class. I may be wrong, if you encrypt something, close the app, and then try to decrypt it, it will not be able to because a different key will be generated. Because I do need this functionality, I am wondering if it's possible to save the key in application settings and whether this is the right way to go?
I am trying to generate CRC32 in my program. Unfortunately it works ~70% of the time. Would that mean that my function doesn't take care of some special case correctly? Can someone give it a quick look and let me know if I did an error while converting C code to vb.net ?
I need change this code to calculate crc16 form file, I found on net only this example. My actualy knowledge in programming is totaly green.
Public Shared Function GetCRC32(ByVal sFileName As String) As String Try Dim FS As FileStream = New FileStream(sFileName, FileMode.Open, FileAccess.Read, FileShare.Read, 8192)
I am retrieving lists of crc32 hashes that contain names of files, not there contents.I need to be able to decrypt the strings which are hashed names like "vacationplans_2010.txt" which are less then 25 characters long.
I want my program the be able to calculate the CRC32 of a file and to change it. I already have the CRC32 calculation class now I wanna know how to make it change the value.
CRC32 calculation class:
Code: Private crc32Table() As Integer Private Const BUFFER_SIZE As Integer = 1024I
I am making a program for a game to change the textures. But when you edit an image file(the texture) it will change CRC32 and the game will notice you changed it so if you start the game the texture will just become grey. So what I want is that you can change the CRC32 code back to the old one that the game wil recognize and the texture won't turn grey. Now I found the CRC32 calculation on the internet but I can't figure out how to change it to the code you want.The CRC32 calculation class:
Option Explicit On Option Strict On <System.Diagnostics.DebuggerStepThrough()> _
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:
i have a scanner set up which scans .bin and .iso files and returns the crc32 checksums (then displays various info based of that etc)
Im looking into adding support for .rar and .zip files, so the end user wont have to extract there files to scan them, how ever that adds to many variable for the crc32's based of what each persons compression is etc. So what about scanning the file inside of the rar/zip file.
So would it be possible to scan a rar or zip file, and get the crc32 of the .iso/.bin located within that archive?
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 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'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 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?
in the current project im making i've decided to add in some tools, 1 of which is a renamer based of a renamer app that already exists (called scdtoolz), i want to build my own version of it so i can learn some new things, and build a nice GUI version of it.[code]So what i have managed to determine is that the current app scans the folders contents for the CRC32 Checksum, and renames based of that, since the 456.bin's CRC32 Checksum was 2274F80B, and in the text file 2274F80B is found here 'WWF - Rage in the Cage (T-81015)(U)#2274F80B#'So now i have determined game identification is based of the CRC32 checksums, how would i go about coding a similar ap in vb.net?first i need to make the app scan a folder, but how to return crcchecksum? and then rename if check = XXXX? If MD4 sums are easier/simpler i can use those instead, im lookin at a few hash app sources now, so i think i can see how to get the md5 but not the crc32 yet, or how to rename the 2 files and folder based of the text file.
