Category

TLS & transport

Every tool and article in this category, gathered in one place.

Tools

Cipher Suite Decoder
Enter a TLS cipher suite, as an IANA name, an OpenSSL or GnuTLS name, or a hex code point, to break it into its key exchange, authentication, cipher, mode, and MAC, with a plain-language security read-out and the official IANA recommendation. Runs entirely in your browser against a bundled copy of the IANA registry.

Articles

Anatomy of a TLS Cipher Suite
What a TLS cipher suite actually names, how to read a suite like TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 piece by piece, and how the same two-byte code point shows up under three different naming conventions.
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Reading Cipher Suite Names: IANA, OpenSSL, and GnuTLS
Why the same cipher suite has three different names and a two-byte code point, how to translate between the IANA, OpenSSL, and GnuTLS conventions, and what the IANA Recommended column of Y, N, and D actually means.
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AEAD vs CBC: Why the Mode Matters
The practical difference between an AEAD cipher like AES-GCM and an older CBC cipher with a separate HMAC, the padding-oracle attacks that killed MAC-then-encrypt, and the one tradeoff AEAD still asks you to make.
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Forward Secrecy and the Key Exchange
What forward secrecy buys you, why static RSA key transport does not provide it, how ECDHE and DHE do, and why authentication and key exchange are two separate jobs that a suite name keeps distinct.
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TLS 1.3 Cipher Suites: What Changed
Why a TLS 1.3 suite names only a cipher and a hash, where the key exchange and authentication went, and why the list of suites shrank from hundreds to a handful.
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What a Quantum Computer Would Break, and What It Would Not
A large quantum computer would not weaken all cryptography equally. Shor's algorithm breaks the public-key math behind RSA, Diffie-Hellman, and elliptic curves outright; Grover's algorithm only halves the strength of symmetric ciphers and hashes, which AES-256 and SHA-384 already survive. This explains the split, why 'harvest now, decrypt later' makes it a today problem, and why a broken candidate like SIKE is a reminder to stay humble.
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The NIST Post-Quantum Standards: ML-KEM, ML-DSA, and SLH-DSA
In August 2024 NIST finalized the first three post-quantum standards: FIPS 203 (ML-KEM, from Kyber) for key establishment, and FIPS 204 (ML-DSA, from Dilithium) and FIPS 205 (SLH-DSA, from SPHINCS+) for signatures. This explains what each one is for, why there are two signature standards on different math, and where HQC and FN-DSA fit as the backups still coming down the pipeline.
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Hybrid Key Exchange in TLS 1.3: What X25519MLKEM768 Does on the Wire
The web did not swap classical key exchange for post-quantum; it runs both at once. X25519MLKEM768 combines a 1990s elliptic curve with lattice-based ML-KEM-768 in a single TLS 1.3 group, so a break of either still leaves the session secure. This covers why hybrid rather than replacement, the wire format and its size problem, and where deployment stands across browsers, servers, and the middleboxes it breaks.
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Inbound TLS: Offload, Bridging, and Passthrough at the Reverse Proxy
A reverse proxy handling inbound HTTPS has three choices for the TLS session: terminate it and send plaintext to the backend (offload), terminate and re-encrypt to the backend (bridging), or forward the encrypted bytes untouched (passthrough). Each trades visibility against confidentiality and cost differently. This explains all three, why the proxy holds the server's certificate, and what SNI and mutual TLS change.
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TLS 1.2 vs TLS 1.3 vs DTLS vs QUIC: One Handshake Family, Four Shapes
TLS 1.2 and TLS 1.3 secure a TCP stream, DTLS carries the same guarantees over datagrams, and QUIC absorbs the TLS 1.3 handshake into the transport itself. What each one is, which RFC defines it today, what actually changed between them, and where each one runs.
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What Is a JA4 TLS Fingerprint?
How a TLS ClientHello becomes a stable fingerprint of the client software, why JA3 faded once browsers began randomizing extension order, how JA4 fixes that by sorting before hashing, and what JA4 can and cannot tell you.
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Why Do We Say SSL When We Mean TLS?
SSL has been prohibited, deprecated, and dead for years - and the industry still sells 'SSL certificates,' configures 'SSL inspection,' and links openssl. The history explains the habit: Netscape's SSL, the political rename to TLS in 1999 (the wire version field still said 3.1), and a quarter century of marketing inertia. Plus the musing the question deserves: what would a protocol-independent name even look like, and do any exist?
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