토큰 발급

발급과 검증

dotnet add package System.IdentityModel.Tokens.Jwt

서명 key

var key = new SymmetricSecurityKey(
    Encoding.UTF8.GetBytes(configuration["Jwt:Key"]!));

SigningCredentials

var creds = new SigningCredentials(
    key,
    SecurityAlgorithms.HmacSha256);

claims 구성

var claims = new List<Claim>
{
    new Claim(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
    new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
    new Claim(ClaimTypes.Name, user.UserName),
    new Claim(ClaimTypes.Role, user.Role)
};

JwtSecurityToken 생성

var token = new JwtSecurityToken(
    issuer: configuration["Jwt:Issuer"],
    audience: configuration["Jwt:Audience"],
    claims: claims,
    notBefore: DateTime.UtcNow,
    expires: DateTime.UtcNow.AddMinutes(15),
    signingCredentials: creds);

문자열로 직렬화

var handler = new JwtSecurityTokenHandler();
string jwt = handler.WriteToken(token);
// jwt now looks like eyJhbGciOiJI...

재사용 가능한 token 서비스

public class TokenService(IConfiguration config)
{
    public string CreateAccessToken(AppUser user)
    {
        var key = new SymmetricSecurityKey(
            Encoding.UTF8.GetBytes(config["Jwt:Key"]!));
        var creds = new SigningCredentials(
            key, SecurityAlgorithms.HmacSha256);
        var claims = new[]
        {
            new Claim(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
            new Claim(ClaimTypes.Role, user.Role)
        };
        var token = new JwtSecurityToken(
            config["Jwt:Issuer"], config["Jwt:Audience"],
            claims, expires: DateTime.UtcNow.AddMinutes(15),
            signingCredentials: creds);
        return new JwtSecurityTokenHandler().WriteToken(token);
    }
}

로그인 엔드포인트 연결

app.MapPost("/login", (LoginDto dto, TokenService tokens) =>
{
    var user = Authenticate(dto.Username, dto.Password);
    if (user is null) return Results.Unauthorized();
    return Results.Ok(new { accessToken = tokens.CreateAccessToken(user) });
});

대칭 방식과 비대칭 방식 비교

var creds = new SigningCredentials(
    new RsaSecurityKey(rsaPrivateKey),
    SecurityAlgorithms.RsaSha256);

서비스 등록

builder.Services.AddScoped<TokenService>();

token을 간결하고 짧게 유지하기

expires: DateTime.UtcNow.AddMinutes(15)

빠른 확인

복습