How can I generate a cryptographically secure pseudorandom number in C#?

Question

Is there any fast implementation of cryptographically secure pseudorandom number generator (CSPRNG) for C# 3.0 (.NET Framework 3.5), for authentication tokens?

user_4552819 · Answer

Upd 2022 in .Net 6 RNGCryptoServiceProvider() is obsolete, usage of static methods of RandomNumberGenerator is recommended

private string GetRandomlyGenerateBase64String(int count)
{
    return Convert.ToBase64String(RandomNumberGenerator.GetBytes(count));
}