I am developing an ASP.NET Core Web API and want to use JWT (JSON Web Tokens) for authentication. I want to sign the tokens using RSA encryption. The API should be deployable on both Linux and Windows servers, so the solution must be cross-platform.
Below is my current code for generating the JWT token and exporting the private key:
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Security.Cryptography;
using Microsoft.IdentityModel.Tokens;
public class JwtTokenGenerator
{
private readonly RSA _rsa;
private readonly RsaSecurityKey _rsaSecurityKey;
private readonly string _issuer;
private readonly string _audience;
public JwtTokenGenerator(string issuer, string audience)
{
_issuer = issuer;
_audience = audience;
// Generate RSA key
_rsa = RSA.Create();
_rsa.KeySize = 2048; // Set key size
_rsaSecurityKey = new RsaSecurityKey(_rsa);
}
/// <summary>
/// Generates a JWT token
/// </summary>
/// <param name="claims">List of claims for the token</param>
/// <param name="expiresInMinutes">Token validity in minutes</param>
/// <returns>The generated JWT token as a string</returns>
public string GenerateToken(Claim[] claims, int expiresInMinutes)
{
var signingCredentials = new SigningCredentials(_rsaSecurityKey, SecurityAlgorithms.RsaSha256);
var tokenDescriptor = new SecurityTokenDescriptor
{
Subject = new ClaimsIdentity(claims),
Expires = DateTime.UtcNow.AddMinutes(expiresInMinutes),
Issuer = _issuer,
Audience = _audience,
SigningCredentials = signingCredentials
};
var tokenHandler = new JwtSecurityTokenHandler();
var token = tokenHandler.CreateToken(tokenDescriptor);
return tokenHandler.WriteToken(token);
}
/// <summary>
/// Exports the private RSA key as XML
/// </summary>
/// <returns>The private key as an XML string</returns>
public string ExportPrivateKey()
{
return _rsa.ToXmlString(true); // Export the private key
}
}
QUESTION: Where can I store the private key safely? Environment variables? I know that storing it in the code or a--settings is not the proper way. If you have an answer, please explain it a little bit. Thanks you
