How to calculate PublisherID from Publisher?

I was very close in my guess of how the PublisherId value is constructed. I heard some whispering...

The value is a Crockford’s Base32 encoding of the first eight bytes of SHA-256 hash of the publisher string in UTF-16 (little endian). I have a good implementation that I validated using the sample values from my question.

Or you simply use the Kernel32.dll Method PackageFamilyNameFromId:

private static string GetPackageFamilyName(string name, string publisherId)
{
  string packageFamilyName = null;
  PACKAGE_ID packageId = new PACKAGE_ID
  {
    name = name,
    publisher = publisherId
  };
  uint packageFamilyNameLength = 0;
  //First get the length of the Package Name -> Pass NULL as Output Buffer
  if (PackageFamilyNameFromId(packageId, ref packageFamilyNameLength, null) == 122) //ERROR_INSUFFICIENT_BUFFER
  {
    StringBuilder packageFamilyNameBuilder = new StringBuilder((int)packageFamilyNameLength);
    if (PackageFamilyNameFromId(packageId, ref packageFamilyNameLength, packageFamilyNameBuilder) == 0)
    {
      packageFamilyName = packageFamilyNameBuilder.ToString();
    }
  }
  return packageFamilyName;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode, Pack = 4)]
private class PACKAGE_ID
{
  public uint reserved;
  public uint processorArchitecture;
  public ulong version;
  public string name;
  public string publisher;
  public string resourceId;
  public string publisherId;
}


[DllImport("kernel32.dll", CharSet = CharSet.Unicode, ExactSpelling = true)]
private static extern uint PackageFamilyNameFromId(PACKAGE_ID packageId, ref uint packageFamilyNameLength, StringBuilder packageFamilyName);

public static void TestMethod()
{
  GetPackageFamilyName("MyCompany.TestApp", "CN=YourPublisherId");
}