Update Microsoft.Bcl.Cryptography/src/PACKAGE.md

src/libraries/Microsoft.Bcl.Cryptography/src/PACKAGE.md

@@ -1,44 +1,39 @@
 ## About
 
-<!-- A description of the package and where one can find more documentation -->
-
-
+This library provides some cryptographic types and functionality for .NET Standard and .NET Framework. This library is not necessary nor recommended when targeting versions of .NET that include the relevant support.
 
 ## Key Features
 
-<!-- The key features of this package -->
-
-*
-*
-*
+* Enables the use of some cryptographic functionality on older .NET platforms.
 
 ## How to Use
 
-<!-- A compelling example on how to use this package with code, as well as any specific guidelines for when to use the package -->
+This package should only be used by platforms where the desired functionality is not built-in.
 
-## Main Types
+```C#
+using System.Security.Cryptography;
+
+internal static class Program
+{
+    private static void Main()
+    {
+        byte[] key = LoadKey();
+        SP800108HmacCounterKdf kbkdf = new(key, HashAlgorithmName.SHA256);
+        byte[] derivedKey = kbkdf.DeriveKey("label"u8, "context"u8, derivedKeyLengthInBytes: 32);
+    }
+}
+```
 
-<!-- The main types provided in this library -->
+## Main Types
 
 The main types provided by this library are:
 
-* ``
-* ``
-* ``
+* `System.Security.Cryptography.SP800108HmacCounterKdf`
 
 ## Additional Documentation
 
-<!-- Links to further documentation. Remove conceptual documentation if not available for the library. -->
-
-* [Conceptual documentation](https://learn.microsoft.com/en-us/dotnet/standard/serialization/**LIBRARYNAME**/overview)
-* [API documentation](https://learn.microsoft.com/en-us/dotnet/api/**LIBRARYNAME**)
-
-## Related Packages
-
-<!-- The related packages associated with this package -->
+* [API documentation](https://learn.microsoft.com/en-us/dotnet/api/System.Security.Cryptography)
 
 ## Feedback & Contributing
 
-<!-- How to provide feedback on this package and contribute to it -->
-
-Microsoft.Bcl.Cryptography is released as open source under the [MIT license](https://licenses.nuget.org/MIT). Bug reports and contributions are welcome at [the GitHub repository](https://github.com/dotnet/runtime).
+Microsoft.Bcl.Cryptography is released as open source under the [MIT license](https://licenses.nuget.org/MIT). Bug reports and contributions are welcome at [the GitHub repository](https://github.com/dotnet/runtime).