There is now an MS-supported implementation of PBKDF2 (for .NET Standard 1.3 and .NET Framework 4.5.1 targets) in the Microsoft.AspNetCore.Cryptography.KeyDerivation Nuget package (note that contrary to the package name, it is not for ASP.NET Core exclusively). When possible, that package should be preferred to this one.
More information here: https://docs.asp.net/en/latest/security/data-protection/consumer-apis/password-hashing.html

Flexible PBKDF2 implementation for the .NET Framework.

The PBKDF2 implementation included with .NET 2.0 and newer - Rfc2898DeriveBytes - is hardcoded to use HMAC-SHA1 as the underlying pseudo random function (PRF).

Jither.PBKDF2 consists of:

• PBKDF2DeriveBytes - which allows a custom PRF through a simple IPseudoRandomFunction interface.
• A few example implementations of IPseudoRandomFunction using other .NET HMAC implementations (HMAC-SHA256, HMAC-SHA512 etc.)
• A small suite of tests, mainly checking output against published test vectors.
• A quickly hacked together test tool (AwpTest) for anti-weakpasswords

Since PBKDF2DeriveBytes subclasses DeriveBytes (like Rfc2898DeriveBytes) usage is similar:

using (var prf = new HMACSHA512PseudoRandomFunction(input))
{
    using (var hash = new PBKDF2DeriveBytes(prf, salt, 1000))
    {
        var result = hash.GetBytes(32);
    }
}

Important note on targets The master/default branch targets .NET Framework 4.5.1 (because that's what I currently use. There's also a "net3.5" branch targetting .NET Framework 3.5 Client Profile.

Note:

Although the code in this repository is extracted from production code, it is mainly intended for educational purposes and something to build upon - not as a full-fledged library.