System.Security.Claims.ClaimsIdentity.AddClaims C# (CSharp) Method

        public virtual void AddClaims(IEnumerable<Claim> claims)
        {
            if (claims == null)
            {
                throw new ArgumentNullException(nameof(claims));
            }

            Contract.EndContractBlock();

            foreach (Claim claim in claims)
            {
                if (claim == null)
                {
                    continue;
                }

                if (object.ReferenceEquals(claim.Subject, this))
                {
                    _instanceClaims.Add(claim);
                }
                else
                {
                    _instanceClaims.Add(claim.Clone(this));
                }
            }
        }

        public ClaimsIdentity ProcessClientCertificate(X509Certificate2 cert, string ipAddress)
        {
            using (var per = PersistenceFactory())
            {
                var hash = cert.GetCertHash();
                var client = per.ClientGetByCertificateHash(hash);

                // not found? add to pending certificates list
                if (client == null)
                {
                    TraceSource.TraceInformation("Pending certificate:\n{0} ({1})", ByteArrayHelper.ByteArrayToString(hash), ipAddress);
                    per.PendingCertificateAddOrUpdate(hash, ipAddress);
                    per.Save();
                }

                // build identity
                var identity = new ClaimsIdentity("ClientAuthentication");
                identity.AddClaim(new Claim(CertificateHashClaimType, ByteArrayHelper.ByteArrayToString(hash), ClaimValueTypes.HexBinary, ClaimIssuer));
                identity.AddClaim(new Claim(IsKnownClaimType, client == null ? "false" : "true", ClaimValueTypes.Boolean, ClaimIssuer)); // known client?

                // add details only if authenticated
                if (client != null)
                {
                    identity.AddClaim(new Claim(identity.NameClaimType, client.Name, ClaimValueTypes.String, ClaimIssuer)); // nick name
                    identity.AddClaim(new Claim(ClientIdClaimType, client.Id.ToString(), ClaimValueTypes.Integer, ClaimIssuer)); // ID
                    identity.AddClaims(client.ClientGroups.Select(group => new Claim(identity.RoleClaimType, group.Id.ToString(), ClaimValueTypes.Integer, ClaimIssuer))); // assigned groups
                    identity.AddClaims(client.ClientGroups.Select(group => new Claim(RoleNameClaimType, group.Name, ClaimValueTypes.String, ClaimIssuer))); // assigned groups (names - informative)
                }

                return identity;
            }
        }