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223 articles
What are Sender-Constrained Tokens? An Introduction to mTLS (RFC 8705) and DPoP (RFC 9449)
Explains sender-constrained tokens that address the weakness of bearer tokens, using mTLS (RFC 8705) and DPoP (RFC 9449) to bind a token to its sender, plus Resource Indicators (RFC 8707) that narrow the audience.
What is Dynamic Client Registration (DCR)? An Introduction to RFC 7591 and 7592
Explains Dynamic Client Registration (RFC 7591) and Client Registration Management (RFC 7592), which register and manage OAuth clients via an API. Covers the registration endpoint, registration access token, and security considerations.
OIDC Logout and Security Event Token (SET)
Explains OpenID Connect Front-Channel Logout and Back-Channel Logout, and how the Security Event Token (RFC 8417 SET) enables session revocation and event notification.
Access Token Validation and Revocation: Introspection, JWT AT, and Revocation
Compares the two access token approaches (opaque + Introspection / JWT access tokens) and how each is validated, plus revocation via Token Revocation. Covers RFC 7662, RFC 9068, and RFC 7009.
What are OpenID Connect Discovery and Metadata? Auto-configuration and Key Retrieval
Explains the role of the OpenID Connect ID Token and how Discovery (OpenID Connect Discovery / RFC 8414 AS Metadata) enables auto-configuration and public key retrieval, including key rotation via jwks_uri.
What is OAuth 2.1? Changes from OAuth 2.0 and the Security BCP (RFC 9700)
An overview of the changes from OAuth 2.0 to 2.1 and the security measures shown by RFC 9700 Security BCP and RFC 6819 threat model. Covers mandatory PKCE, deprecation of the Implicit grant, Mix-Up defenses, and more.
What is JOSE? An Overview of JWT, JWS, JWE, JWK, and JWA
An overview of the JOSE family (JWT/JWS/JWE/JWK/JWA). Learn the difference between JWT and JWS, the 3-part signed structure and 5-part encrypted structure, and how JWT BCP (RFC 8725) prevents alg confusion and none attacks.
Cryptography Fundamentals: Symmetric, Asymmetric, One-Way Functions, Hashing, and Digital Signatures
From symmetric versus asymmetric encryption to the one-way and trapdoor functions behind RSA and ECC, plus hash functions and digital signatures, this article explains the building blocks of cryptography with primary sources. Part 1 of a three-part series that groups public-key uses into signing, encryption, and key exchange.
Cryptography in Practice: TLS, JWT, and SSH
How everyday protocols such as TLS, JWT/JWS, and SSH combine symmetric keys, public keys, signatures, key exchange, and PKI, viewed through the three uses of a public key and backed by RFCs. The final part of a three-part cryptography series.
Key Exchange and PKI: Diffie-Hellman, Certificates, and Certificate Authorities
How Diffie-Hellman shares a symmetric key safely, how ECDHE adds forward secrecy, and how PKI binds a public key to its owner through certificates, CAs, and a chain of trust. Backed by primary sources such as RFCs. Part 2 of a three-part cryptography series.
Three Uses of a Public Key: Signing, Encryption, and Key Exchange
A public key has just three uses: signing, encryption, and key exchange. This article sorts real-world applications such as SSH public-key auth, WebAuthn, mTLS, private_key_jwt, code signing, and container signing into these three, and clarifies how they differ from shared-key schemes such as HMAC, with primary sources.
Comparing Data Transformation Methods: Encoding, Serialization, Encryption, Hashing, Compression, Compilation, and Parsing
A concise comparison of common data transformation methods — encoding, serialization, encryption, hashing, compression, compilation, and parsing — across three axes: reversibility, whether a key is required, and purpose.
パスキーのすべて: Adoption, UX Design, and Implementation
パスキーのすべて: Adoption, UX Design, and Implementation
Python for Algorithmic Trading
Python for Algorithmic Trading
Introducing Asset Trend Simulator — An iPhone App for Compound Interest Simulation
A deep dive into Asset Trend Simulator, an iPhone app built with Flutter and Riverpod that simulates future net worth trends using compound interest calculations based on your household finances.
Introducing Bookstacks — An iPhone Bookshelf App with ISBN Barcode Scanning
A deep dive into Bookstacks, an iPhone app built with Flutter and Riverpod that lets you register books via ISBN barcode scan and organise them with customisable labels.
Introducing Done Log — A Daily Routine Tracker iPhone App
An introduction to Done Log, an iPhone app built with Flutter and Riverpod for tracking daily routine tasks with a flexible recurrence rule engine — daily, every N days, specific weekdays, or once.
Introduction to Digital Identity: Essential Authentication, Authorization, and ID Management for Web Services
Introduction to Digital Identity: Essential Authentication, Authorization, and ID Management for Web Services
Steps for Code Reading Using AI
Master code reading procedures using AI by creating documentation, checklists, and improvement notes to accelerate comprehension and analysis.
The Go Programming Language, 2nd Edition: An Idiomatic Go Practical Guide for Programmers from Other Languages
The Go Programming Language, 2nd Edition: An Idiomatic Go Practical Guide for Programmers from Other Languages