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Add kdf module: Key Derivation Function API (JEP 510, final in JDK 25), HKDF, RFC 5869 vectors, interop with Python cryptography and openssl, per-tenant keys

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Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b7rnC7jppGGdHGESvy
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asmhatre
2026-10-28 18:07:57 +00:00
co-authored by Claude Sonnet 5.5
parent c93a1fffbb
commit eca73ad544
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@@ -72,6 +72,7 @@ These modules keep only sources, a `run.sh` and their transcripts (`output/`). T
| [`compact-strings/`](compact-strings) | Compact Strings in Java: Measured with JOL on JDK 25 (plus Compact Object Headers) | the `String` object and its `byte[]` field by field, Latin-1 vs UTF-16 footprint by length, one million strings with and without `-XX:-CompactStrings`, what flips a string to UTF-16 (and what flips it back), compact object headers on JDK 25 (opt-in) vs 27 (default), a JMH comparison of six operations |
| [`pem-api/`](pem-api) | PEM Encodings in Java (JEP 538/542): Read and Write Keys and Certificates Without BouncyCastle | `PEMDecoder`/`PEMEncoder` round trips, JWT signing (RS256/ES256/EdDSA) and a TLS server built from PEM files, encrypted PKCS#8 keys, the failure catalogue (wrong target class, SEC1 `EC PRIVATE KEY`, CRLF output), BouncyCastle and Spring Security `RsaKeyConverters` side by side, preview flag on JDK 27 vs the JDK 28 EA build |
| [`structured-concurrency-final/`](structured-concurrency-final) | Structured Concurrency Is Final in JDK 28 (JEP 543): From Preview to Production | the thread leak of `ExecutorService` and its fix, every built-in `Joiner`, structure violations, timeouts, a custom joiner, JSON thread dumps, scoped values, `javap` diffs of the API on JDK 25, 26, 27 and 28-ea, the compiler output for six pieces of 25/26-era code, and the preview class-file trap between 27 and 28 |
| [`kdf/`](kdf) | Key Derivation Function API in Java (JEP 510): HKDF Explained with Real Examples | `javax.crypto.KDF` final in JDK 25, `HKDF-SHA256/384/512`, extract vs expand, RFC 5869 vectors asserted, a hand-written HKDF and 300 generated cases compared with Python `cryptography` and `openssl kdf`, per-tenant keys with length-prefixed `info`, and the mistakes reproduced (same `info`, ambiguous concatenation, PIN through HKDF vs PBKDF2) |
## Captured output (`docs/output/`)