JWT Bearer – Api Asp.Net

            //JWT
            services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            }).AddJwtBearer(options => {
                options.TokenValidationParameters = new TokenValidationParameters
                {

                    ValidateIssuer = true, //Validar Emisor
                    ValidateAudience = true, //Validar Audiencia
                    ValidateLifetime = true, //Validar tiempo
                    ValidateIssuerSigningKey = true, //Validar la firma del emisor
                    ValidIssuer = Configuration["Authentication:Issuer"], //Accdemos a valores que tenems en el appsetting.json
                    ValidAudience = Configuration["Authentication:Audience"],
                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(Configuration["Authentication:Secretkey"])) //Secret Key

                };
            });

app.UseAuthentication(); //JWT
app.UseAuthorization();

        public async Task<EmpleadoModel> GetUserCredentials(UserLogin login)
        {
            var sql = from empleado in _context.Empleados
                      join roles in _context.Roles on empleado.Rol equals roles.Id
                      select new EmpleadoModel
                      {
                          Id = empleado.Id,
                          Documento = empleado.Documento,
                          Nombres = empleado.Nombres,
                          Apellidos = empleado.Apellidos,
                          Roles = new RolModel
                          {
                              Descripcion = roles.Descripcion,
                          }
                      };

            var response = await sql.FirstOrDefaultAsync(x =>
                                    x.Documento == login.User);
            return response;
        }

    public class TokenController : ControllerBase
    {
        private readonly IConfiguration _configuration;
        private readonly ISecurityService _securityService;
        public TokenController(IConfiguration configuration, ISecurityService securityService)
        {
            _configuration = configuration;
            _securityService = securityService;
        }

        [HttpPost]
        public async Task<IActionResult> Authentication(UserLogin userLogin)
        {
            var validation = await isValidaUser(userLogin);

            if (validation.Item1)
            {
                var token = GenerateToken(validation.Item2);
                return Ok(new { token });
            }
            return BadRequest();
        }

        private async Task<(bool, EmpleadoModel)> isValidaUser(UserLogin userLogin)
        {
            var response = await _securityService.GetUserCredentials(userLogin);
            return (response != null, response);
        }

        private string GenerateToken(EmpleadoModel security)
        {

            var symmetricSecurityKry = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration["Authentication:Secretkey"]));
            var signingCredentials = new SigningCredentials(symmetricSecurityKry, SecurityAlgorithms.HmacSha256);
            var header = new JwtHeader(signingCredentials);

            var claims = new[]
            {
                new Claim(ClaimTypes.Name, $"{security.Nombres} {security.Apellidos}"),
                new Claim("Email", ""),
                new Claim(ClaimTypes.Role, security.Roles.Descripcion),
            };

            var payload = new JwtPayload
            (
                _configuration["Authentication:Issuer"],
                _configuration["Authentication:Audience"],
                claims,
                DateTime.Now,
                DateTime.UtcNow.AddMinutes(10)
            );

            var token = new JwtSecurityToken(header, payload);

            return new JwtSecurityTokenHandler().WriteToken(token);
        }
    }