title: How to calculate HMAC-SHA1 authentication code in .NET 4.5 Core
body: <p>I’m currently facing a big problem (Environment: .NET 4.5 Core): We need to protect a message with a key using a HMAC-SHA1 algorithm. The problem is that the HMACSHA1-class of the namespace <code>System.Security.Cryptography</code> and the namespace itself do not exist in .NET 4.5 Core, this namespace only exists in the normal version of .NET.</p>
  
  <p>I tried a lot of ways to find an equivalent namespace for our purpose but the only thing I found was <code>Windows.Security.Cryptography</code> which sadly does not offer a HMAC-Encryption. </p>
  
  <p>Does anyone have an idea how I could solve our problem or is there any free to use 3rd-party solution?</p>