HmacSha512.cs

using System.Security.Cryptography;
using System.Text;
using Waher.Content;
 
namespace Waher.Security.JWS
{
    public class HmacSha512 : HmacSha
    {
        private HMACSHA512 hmacSHA512;
 
        public HmacSha512()
        {
            using (RandomNumberGenerator Rnd = RandomNumberGenerator.Create())
            {
                byte[] Secret = new byte[64];
                Rnd.GetBytes(Secret);
 
                this.Init(Secret);
            }
        }
 
        public HmacSha512(byte[] Secret)
        {
            this.Init(Secret);
        }
 
        private void Init(byte[] Secret)
        {
            this.hmacSHA512 = new HMACSHA512(Secret);
        }
 
        public override void Dispose()
        {
            if (!(this.hmacSHA512 is null))
            {
                this.hmacSHA512.Dispose();
                this.hmacSHA512 = null;
            }
        }
 
        public override string Name => "HS512";
 
        public override string Sign(string HeaderEncoded, string PayloadEncoded)
        {
            byte[] SignatureBin;
            string Token = HeaderEncoded + "." + PayloadEncoded;
            byte[] TokenBin = Encoding.ASCII.GetBytes(Token);
 
            lock (this.hmacSHA512)
            {
                SignatureBin = this.hmacSHA512.ComputeHash(TokenBin);
            }
 
            return Base64Url.Encode(SignatureBin);
        }
    }
}