JwtService.cs

public class JwtService
    {
        private string _secret;
        private int _expDate;
        private IConfiguration _config;

        public JwtService(IConfiguration config)
        {
            _secret = config.GetSection("JwtConfig").GetSection("secret").Value;
            _config = config;
            _expDate = int.Parse(config.GetSection("JwtConfig").GetSection("expirationInMinutes").Value);
        }

    public static RSAParameters FromXmlString(string xmlString)
    {
                var parameters = new RSAParameters();
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.LoadXml(xmlString);
    
                if (xmlDoc.DocumentElement.Name.Equals("RSAKeyValue"))
                {
                    foreach (XmlNode node in xmlDoc.DocumentElement.ChildNodes)
                    {
                        switch (node.Name)
                        {
                            case "Modulus":
                                parameters.Modulus = Convert.FromBase64String(node.InnerText);
                                break;
                            case "Exponent":
                                parameters.Exponent = Convert.FromBase64String(node.InnerText);
                                break;
                            case "P":
                                parameters.P = Convert.FromBase64String(node.InnerText);
                                break;
                            case "Q":
                                parameters.Q = Convert.FromBase64String(node.InnerText);
                                break;
                            case "DP":
                                parameters.DP = Convert.FromBase64String(node.InnerText);
                                break;
                            case "DQ":
                                parameters.DQ = Convert.FromBase64String(node.InnerText);
                                break;
                            case "InverseQ":
                                parameters.InverseQ = Convert.FromBase64String(node.InnerText);
                                break;
                            case "D":
                                parameters.D = Convert.FromBase64String(node.InnerText);
                                break;
                        }
                    }
                }
                else
                {
                    throw new Exception("Invalid XML RSA key.");
                }
    
                //then use rsa.Import
                return parameters;
            }
    
            public RsaSecurityKey getSecurityKeyFromParam(string location)
            {
                 var publicRsa = RSA.Create();
    
                var publicXMLContent = File.ReadAllText(location);
                publicRsa.ImportParameters(FromXmlString(publicXMLContent));
    
                return new RsaSecurityKey(publicRsa);
            }
    
            private SigningCredentials ProcessPrivateKey(string location)
            {
                return new SigningCredentials(getSecurityKeyFromParam(location), SecurityAlgorithms.RsaSha256);
            }

            public string GenerateToken(string email)
                    {
                        SigningCredentials pkey = ProcessPrivateKey(_config.GetSection("JwtConfig").GetSection("privateXml").Value);
            
                        var tokenHandler = new JwtSecurityTokenHandler();
                        var tokenDescriptor = new SecurityTokenDescriptor
                        {
                            Subject = new ClaimsIdentity(new[]
                            {
                                new Claim(ClaimTypes.Email, email)
                            }),
                            // Audience = "localhost",
                            
                            Issuer = _config.GetSection("JwtConfig").GetSection("Issuer").Value,
                            Expires = DateTime.UtcNow.AddMinutes(_expDate),
                            SigningCredentials = pkey
                        };
            
                        var token = tokenHandler.CreateToken(tokenDescriptor);
            
                        return tokenHandler.WriteToken(token);
                    }
                }

    }