Please add support for .NET Framework versions 4.0/4.5/4.6/4.7/4.8.

https://www.lammertbies.nl/comm/info/crc-calculation

It is very useful for industry communication.

I've tested out all of the algorithms, and I've been comparing them to CyberChef since that's the app I use the most (via https://gchq.github.io/CyberChef/)

Is CyberChef using a different type of CRC algo? Or am I missing a vital setting in yours. Because I've tested out about every variation of CRC16 I can, and I never get the values that I get in CyberChef.

However, CRC32 seems to be fine.

The CRC16 in my case calculated for bytes[5..last-2].
For example, CRC16 for request "F8 55 CE 01 00 23 23 00" will be "23 00".
For example, CRC16 for response "F8 55 CE 0D 00 24 00 00 00 00 01 01 00 01 00 00 00 00 FC 23" will be "FC 23".

// using text
var text = "I am string content";
// convert text to a byte array
var textBuffer = System.Text.Encoding.UTF8.GetBytes ( text );
// get the CRC for the text
var textCrc = NullFX.CRC.Crc32.ComputeChecksum ( textBuffer );
Console.WriteLine ( "Text CRC: {0:X8}", textCrc );

How to get the result string with small character instead of capital character.
for "I am string content"
3ad00fd2 instad of value "3AD00FD2"
I check from online this site the result are return with small character CRC32 value.

Hello

Is possible to make NullFX.CRC Targets .NET Standard 2.0?

That will make the library compatible with all .NET implementations specified here in one shot:
https://learn.microsoft.com/en-us/dotnet/standard/net-standard?tabs=net-standard-2-0

This is useful when your library is integrated in another .NET Standard project to have a common base between .NET and .NET Framework.

Thanks

If you have a 60 byte buffer and need to do a CRC on byte offsets 30-39, the CRC is not calculated.

The conditional check start < length prevents the CRC from being calculated.

Example Call:

var crc = ComputeChecksum(myBytes, 30, 10);

Hello, I try to use the Crc16Algorithm.CcittKermit, but its giving me wrong results.

var rawValue = 3218461.ToString();
var bytes = Encoding.UTF8.GetBytes(rawValue);
var raw = NullFX.CRC.Crc16.ComputeChecksum(Crc16Algorithm.CcittKermit, bytes);
var a = string.Format("0x{0:X}", NullFX.CRC.Crc16.ComputeChecksum(Crc16Algorithm.CcittKermit, bytes));

a result = 0xAAE0
But checking on https://crccalc.com/?crc=3218461&method=crc16&datatype=ascii&outtype=0 the result should be 0xE0AA

As you can see, the correct characters are there, just not in the right order and this happens for every input I throw at it. So my quickfix was just to do this: var fixedValue = $"{a[0]}{a[1]}{a[4]}{a[5]}{a[2]}{a[3]}"; But it would be nice if the correct output comes out of the ComputedCheckSum methods.

I am not sure if I am doing something wrong with the package or that there is a bug? I have the feeling I am doing something wrong, but I have no experience in this area.

EDIT: fix for ComputeChecksum

raw = SwapBytes(raw );
var a = string.Format("0x{0:X}", raw );

public static ushort SwapBytes(ushort x)
      {
          byte[] bytes = BitConverter.GetBytes(x);

          Array.Reverse(bytes);
          return BitConverter.ToUInt16(bytes, 0);
      }