https://www.youngju.dev/blog 천천히 올바르게. AI Researcher & DevOps Engineer Youngju's blog. GPU/CUDA, LLM, MLOps, Kubernetes AI workloads, and data engineering — plus mindset essays on confidence, routines, health, and sport psychology. ko fjvbn2003@gmail.com (Youngju Kim) fjvbn2003@gmail.com (Youngju Kim) Sat, 15 Aug 2026 00:00:00 GMT https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization.en https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization.en OAuth 2.0 is an authorization framework; OIDC is the authentication layer on top of it. This guide corrects the flows that fell out of the recommendations, the illusion of JWT validation, and the real trade-offs of token storage — using the text of RFC 6749, 9700, 7636, 7519, 8725, OIDC Core, and the OWASP cheat sheets. If the existing OAuth deep dive was about how it works, this one is about where it goes wrong. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 인증인가oauthoidcjwt보안세션 https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization.ja https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization.ja OAuth 2.0 は認可フレームワークであり、その上に認証を載せるのが OIDC です。推奨から外れたフロー、JWT 検証をめぐる錯覚、トークン保存場所のトレードオフを、RFC 6749・9700・7636・7519・8725、OIDC Core、OWASP チートシートの原文で整理します。既存の OAuth 詳解が「どう動くか」なら、この記事は「どこで間違えるか」です。 Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 인증인가oauthoidcjwt보안세션 https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization https://www.youngju.dev/blog/architecture/2026-08-15-guide-auth-and-authorization OAuth 2.0은 인가 프레임워크이고 OIDC가 그 위에 인증을 얹습니다. 권장에서 빠진 플로우, JWT 검증에 대한 착각, 토큰 저장 위치의 교환 조건을 RFC 6749·9700·7636·7519·8725와 OIDC Core, OWASP 치트시트 원문으로 정리합니다. 기존 OAuth 심화 글이 "어떻게 동작하는가"였다면 이 글은 "어디서 틀리는가"입니다. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 인증인가oauthoidcjwt보안세션 https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control.en https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control.en Starts from the structure of nftables and lays out what firewalld and ufw do on top of it. Covers the procedure that keeps you from locking yourself out while changing rules remotely, and the diagnostic order for when rules do not take effect. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스방화벽nftablesfirewalld보안네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control.ja https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control.ja nftablesの構造から出発し、firewalldとufwがその上で何をしているのかを整理します。リモートでルールを変更する際に自分自身を締め出さない手順と、ルールが適用されないときの診断順序を扱います。 Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스방화벽nftablesfirewalld보안네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control https://www.youngju.dev/blog/linux/2026-08-15-guide-firewall-and-access-control nftables의 구조에서 출발해 firewalld와 ufw가 그 위에서 무엇을 하는지 정리합니다. 원격에서 규칙을 바꾸다 스스로 잠기지 않는 절차와 규칙이 적용되지 않을 때의 진단 순서를 다룹니다. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스방화벽nftablesfirewalld보안네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh.en https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh.en sshd_config hardening, choosing and distributing key types, ProxyJump and port forwarding, and the layered order to debug a connection that will not come up, organised from an operator viewpoint. Includes the procedure that keeps you from locking yourself out while changing configuration. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스ssh보안운영서버관리네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh.ja https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh.ja sshd_config のハードニング、鍵の種類の選択と配布、ProxyJump とポートフォワーディング、接続できないときのデバッグ順序までを運用者の視点で整理します。設定を変更している最中に自分自身をロックアウトしないための手順も含みます。 Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스ssh보안운영서버관리네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh https://www.youngju.dev/blog/linux/2026-08-15-guide-ssh sshd_config 하드닝, 키 종류 선택과 배포, ProxyJump와 포트 포워딩, 접속이 안 될 때의 디버깅 순서까지 운영자 관점에서 정리합니다. 설정을 바꾸다 스스로 잠기지 않는 절차를 포함합니다. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스ssh보안운영서버관리네트워크 https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates.en https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates.en A purpose-by-purpose reference of the openssl commands for reading certificates, creating CSRs, verifying chains, converting formats, and diagnosing server connections. Also covers how to identify expiry, a missing chain, and a key mismatch in the field. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스tls인증서openssl보안운영 https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates.ja https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates.ja 証明書を読み、CSRを作り、チェーンを検証し、形式を変換し、サーバー接続を診断するopensslコマンドを目的別に整理します。有効期限切れとチェーン欠落、鍵の不一致を現場で判別する方法まで扱います。 Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스tls인증서openssl보안운영 https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates https://www.youngju.dev/blog/linux/2026-08-15-guide-tls-certificates 인증서를 읽고, CSR을 만들고, 체인을 검증하고, 형식을 변환하고, 서버 연결을 진단하는 openssl 명령을 목적별로 정리합니다. 만료와 체인 누락, 키 불일치를 현장에서 판별하는 방법까지 다룹니다. Sat, 15 Aug 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 리눅스tls인증서openssl보안운영