<p>How do I calculate the CRC32 (Cyclic Redundancy Checksum) of a string in .NET?</p>

This guy seems to have your answer.
https://damieng.com/blog/2006/08/08/calculating_crc32_in_c_and_net
And in case the blog ever goes away or breaks the url, here's the github link:
https://github.com/damieng/DamienGKit/blob/master/CSharp/DamienG.Library/Security/Cryptography/Crc32.cs
Usage of the Crc32 class from the blog post:
```
```
Crc32 crc32 = new Crc32();
String hash = String.Empty;

using (FileStream fs = File.Open("c:\\myfile.txt", FileMode.Open))
  foreach (byte b in crc32.ComputeHash(fs)) hash += b.ToString("x2").ToLower();

Console.WriteLine("CRC-32 is {0}", hash);
```
```