Calculate A Checksum Value To Add To The String As The Last Byte To Be Sent?
Oct 4, 2011
I have the following hex string 40 50 4C 41 59 0D I am transmitting to a piece of equipment, I need to calculate a checksum value to add to the string as the last byte to be sent. The checksum byte is generated in such a manner that the result of addition of all bytes of a message will become 11111111(255). the code that you see here does not work can anyone tell/show me why? Whats important is the checksum calculation.
[Code]...
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Nov 30, 2011
I need to convert a string to get a checksum as follows;
Checksum
The checksum is the 8 LSB (least significant bits) of a simple addition of all octets (note that a message type '30' is two octets with the values 33 hex and 30 hex) following the STX character and until the checksum field. Note that all separators will be included in the checksum, but the STX, checksum and the ETX will not be included.
Dim str as string = "01/00064/O/30/12345678/87654321////////48656C6C6F20576F726C64/"
This should result in checksum = "C2" What type of checksum is this? what should I Google for? CRC, MD5, hash ?
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Dec 31, 2009
This function doesn't work if I change the input argument 'pdu' from a string to an int.Would someone please help me figure out what to do here so that the checksum does not add the ascii value of the int argument but rather the actual integer value?I took out a few lines of the actual function but it adds the input argument to a packet sent out via TCP protocol.This function shows the integer value just fine in the string that gets encoded as a byte array. the checksum is wrong.!
''Public Function buildpacket(pdu As Integer) is what I want.
Public Function buildpacket(pdu As String)
Dim packet As String
[code]....
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Jan 25, 2011
I have a byte array that I convert into a string like so Dim byt As Byte() = New Byte(255) {} s = New String(Encoding.ASCII.GetChars(byte))My question is when I look at the string in a debuger its clearly a normal string but when I compare it to what I know its supposed to be it doesnt equal. So i did a quick check and for some reason its return a string thats the length of 256 characters. So i did a s.trim and it still is 256 characters long.
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Aug 7, 2010
Why does C# define Byte+Byte=Int32 instead of Byte+Byte=Byte like VB?
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Jun 12, 2011
The string itself contains things like "random" & random.next(1,3) & "random2" etc. The string registers all of this as a string and doesn't actually calculate random numbers.Is there any way to fix this?
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Apr 28, 2012
I try to read the ID3 Info from a .mp3 file by reading bytes, and then i convert it to a string, and try to compare it to a string (that contains the same word(s)) but wasnt a byte stream beforehand anyhow ALL of my converted strings have a length of 31, regardless of if its a string that says "John" or a string that says "Teenage Mutant Ninja Turtles" how can i make my converted string have the correct length? John = 4 NOT 31!!??
[code]...
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Mar 17, 2010
I'm working with some very large files residing on P2 (Panasonic) cards. Part of the process we employ is to first generate a checksum of the file we are going to copy, then copy the file, then run a checksum on the file to confirm that it copied OK. The problem is, is that files are large (70 GB+) and take a long time to complete. It's an issue since we will eventually be dealing with thousands of these files.
I would like to find a faster way to generate the checksum other than using the System.Security.Cryptography.MD5CryptoServiceProvider I don't care if this means using a specialized hardware card, provided it works and is not to ungodly expensive. I would prefer to have a method of encoding that provided some feedback as to how far the process has gone along so I can display it like I do now.
The application is written in vb.net. I would prefer to be able to use it as component, library, reference within my application, but I'm willing to call an outside application if there is enough improvement in the speed of generating the checksum.
Needless to say, the checksum must be consistent and correct.
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Feb 23, 2010
This comparison shows the different values of the known good checksum calculation (c#) as used by my client and what I 'hoped' was the vb.net equivalent. How can I get 405 rather than 513 as I currently do?
For i = 0 To length - 2 Step 1
cksum += sendFrameData(i + 5)
Next i
[Code]....
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Jun 10, 2009
I've tried CByte(hex) and Convert.ToByte(hex) neither work :/
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Mar 10, 2010
I am using the .NET Framework 2.0, and I am trying to code a client bot for a game called Minecraft, Originally written in Java, there have been quite a few people who have made custom multi-player servers for this game, Primarily in C#, or in a language that i've never heard of, such as Pascal.I'm looking right now at sending this:
Packet ID: 0x00 (0) As Byte
Protocol Version: 0x07(7) As byte
Username: "umby25" As String
[code].....
"Byte cannot be converted to 1-Dimensional array of byte"
I don't understand why this whole thing would work in all of the other programming languages, but not Visual basic.I have tried converting the string using the same method that one of the open source C# servers used, and it failed, telling me that the dictionary does not contain that or something.
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Apr 21, 2010
i got byte() value as
'1111111111111111AAAAAAAAAAAAAAAA1111111111111111'
i want it to reverse back to string,i don't know how to input back this string into byte() as it is
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Apr 19, 2012
how to get byte from given string it should be something like this
'' input data
Dim str As String = "2D"
'' output data
Dim byte As Byte() = {&H2D}
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Oct 30, 2011
If let's say I have the string "02 3A 00 00", how can I convert it to bytes (as in, I want the byte to be 02 3A 00 00)?
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Sep 14, 2009
Dim sum As Byte
Dim Trans_Array(_64K, 2) As Byte
Const _64K As Integer = 65536
sum = 0
For i = 0 To 15
BinaryStream.Write(Trans_Array(Address + i, RIGHT_FILE))
sum = (Convert.ToByte(sum + Trans_Array(Address + i, RIGHT_FILE)))
Next
I can't figure out how to calculate the checksum of the bytes from array.
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Sep 17, 2011
Is it possible for my application to check if its been modified?
e.g. Could i compile the app and use a 3rd party tool to calculate the MD5 checksum of the compiled exe - and inside the app, code it so that if the MD5 checksum doesnt match then run the deactivation process?
I know its not foolproof but if it makes it slightly more hassle to crack my app i'd rather have it
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Mar 24, 2010
Is there any way to generate checksum for a dll from the main app (compiled) and the main app from the dll when I run the main app or something of this kind?
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May 18, 2009
Is there a method to calculate an equation from a string that looks something like "(1 + 1) * 2"?
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Sep 27, 2010
It's possible to calculate a string that has a formula something like:
dim val as integer
dim formula as string = "(5/1.5) + 10"
val = formula
And the result should be 13.33
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Oct 20, 2009
Is there a method to calculate an equation from a string that looks something like "(1 + 1) * 2"?
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Nov 2, 2011
hI want conver my string to byte array.
how to convert my string to byte array in vb.net?
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Dec 23, 2010
I have string in {&HF3,&HA1,&H01}
i want to convert it to byte array like {&HF3,&HA1,&H01}
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Aug 12, 2009
I have an activex control that outputs a template object to the client, which gets serialized to a byte array. My attempts to put this byte array in a hidden field for post back to the server have given mixed reults, in that the size of the byte array decreases when sent to the server. My best guess is that the byte array is being truncated when put into a (string) hidden field.
I convert the byte array to a HEX string on the client side before passing over to the server, then converting it back on the server - HEX to byte array. If found some examples of how to do this in C#, VB.net but I haven't a clue how to accomplish this on the client - vbscript, javascript, etc,
I'm guessing something like this would get it done on the server, but how would I accomplish this on the client side?
Private Function Bytes_To_String2(ByVal bytes_Input As Byte()) As String
Dim strTemp As New StringBuilder(bytes_Input.Length * 2)
For Each b As Byte In bytes_Input
[Code].....
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Mar 6, 2012
I m using encryption and decryption
When I use Return Convert.ToBase64String(ms.ToArray()), I can decrypt data by first Convert.FromBase64String(stringToDecrypt) and it works fine.
But if I dont use Base64string method when returning the data and use .Encoding.ASCII.GetString(ms.ToArray) and then try to decrypt, I get "Bad data" error
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Feb 26, 2012
i would like to convert a single byte to a string.
dim mybyte as byte = &h11
dim mystring as string
i tried
[code].....
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Mar 8, 2011
I am working on a mini project that requires me to take a 8 byte hex string that I received from the Serial Port and convert it into a Byte Array and display it on the screen.An example of the string that I receive is 01050001FFFF8FFB
I am currently using the System.Text.ASCIIEncoding.ASCII.GetBytes(str) to help me achieve this. However I realised that if this does not support extended ASCII so whatever byte that is > 7F, I will not get the right value.My current code is as follows:
vb
Private Sub SerialPort1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim str As String
[code]....
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Mar 9, 2009
What will be the fastest / most efficient way to copy the contents of a byte array into a string?
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Aug 13, 2010
in my datatable I've a String.Byte[] column which contains the array of bytes of an image. So, when the datatable is binded to the datagrid, I can see the picture, if present, and the red cross if is not presente. So I can remove the red cross, by assign a value to the DefaultValue property of the datacolumn. But what default value I've to assign?? I tried with system.dbnull.value but the red cross is still present.
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Dec 8, 2009
I'm trying to figure out how to convert a string inot a byte array to send as a packet over a socket. Initially it was used for serialport.write but I would like to use in
Socket.BeginSend(ByVal buffer() As Byte buildpacket()
Below is taking a struct (listed at bottom) as an argument and building a string using eg. Chr().
How can I convert the output of buildpacket(), eg. "yyyypyu" into a Byte().
Public Function buildpacket(ByVal packet As PacketRecord) As String
Dim temppacket As String
Dim checksum, i As Integer
'Build packet to Transmit
temppacket = Chr(255) & Chr(255) & Chr(255) & Chr(255) & Chr(254)
[Code] .....
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May 27, 2011
I am trying to write a code that will byte swipe data in a string.
The conversion should take a 16 characters string, and swipe the first to characters with the last two, then characters three and four with character thirteen and fourteen and so on, in this format if the input string is
A1B2C3D4E5F6G7H8 then the converted sting will be H8G7F6E5D4C3B2A1.
I run into problem using: left(mystring 2) and right(mystring -2) because the string to manipulate is an input of a textbox so I fail when I try to use cross data with a StringHandling class, and how to incorporate StringHandling into my form class and without it when I try something like
Dim byte1 As String = Left(MyString, 14)I get an
error saying - Public ReadOnly Property Left As Integer has no parameters and its return type cannot be indexed.
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