Below the basic operations to create and validate JWT tokens
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Security.Cryptography;
using System.Text;
public class JwtGenerator
{
public static string GenerateSecureKey()
{
using var randomNumberGenerator = RandomNumberGenerator.Create();
var key = new byte[32]; // 256 bits
randomNumberGenerator.GetBytes(key);
return Convert.ToBase64String(key);
}
public static string GenerateToken(string secret)
{
JwtSecurityTokenHandler tokenHandler = new();
byte[] key = Encoding.ASCII.GetBytes(secret);
SecurityTokenDescriptor tokenDescriptor = new()
{
Subject = new ClaimsIdentity(new Claim[]
{
// Add any claims you need here
new Claim(ClaimTypes.Name, "username"),
}),
Expires = DateTime.UtcNow.AddMinutes(60),
SigningCredentials =
new SigningCredentials(
new SymmetricSecurityKey(key), SecurityAlgorithms.HmacSha256Signature)
};
SecurityToken token = tokenHandler.CreateToken(tokenDescriptor);
return tokenHandler.WriteToken(token);
}
public static ClaimsPrincipal DecodeAndValidateToken(string token, string key)
{
var tokenValidationParameters = new TokenValidationParameters
{
ValidateIssuerSigningKey = true,
IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(key)),
ValidateIssuer = false,
ValidateAudience = false,
ClockSkew = TimeSpan.Zero
};
var tokenHandler = new JwtSecurityTokenHandler();
try
{
var claimsPrincipal = tokenHandler.ValidateToken(token, tokenValidationParameters, out var validatedToken);
return claimsPrincipal;
}
catch (SecurityTokenException)
{
Console.WriteLine("Invalid token.");
return null;
}
catch (Exception ex)
{
Console.WriteLine($"An error occurred: {ex.Message}");
return null;
}
}
public static void Main()
{
string key = GenerateSecureKey();
Console.WriteLine(key);
Console.WriteLine();
string token = GenerateToken(key);
Console.WriteLine(token);
var claimsPrincipal = DecodeAndValidateToken(token, key);
foreach (var claim in claimsPrincipal.Claims)
{
Console.WriteLine($"Claim Type: {claim.Type}, Claim Value: {claim.Value}");
}
}
}
