サンプル

Prove that Caddy's filter.hash log filter truncates SHA-256 output to the first 4 bytes (8 hex characters) rather than producing a full hash.

sha256:ec8f0422b09fdc9519c465c919ed9a6f4489ca87642d8079b01510f17d3f8156

PUBLISHED L3_CONTRACT_PASS MIT-0

実行証拠

宣言環境と署名済み検証実行を分け、証明範囲を明確にします。

証拠の基準署名済みコントラクト合格

検証レシート1

検証レベルL3_CONTRACT_PASS

CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-17

ゴール: Prove that Caddy's filter.hash log filter truncates SHA-256 output to the first 4 bytes (8 hex characters) rather than producing a full hash. HOW
パッケージ: github.com/caddyserver/caddy/v2 2.11.4
環境: go
作成日: 2026-08-17T22:01:35Z

The filter.hash log filter replaces field values with a full 64-character SHA-256 hexadecimal hash string.

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

Caddy's filter.hash log filter module (caddy.logging.encoders.filter.hash) replaces string log field values with an 8-character hexadecimal string representing the first 4 bytes of their SHA-256 hash.
The filter.hash module is registered in the Caddy module registry under ID caddy.logging.encoders.filter.hash and instantiates as *logging.HashFilter implementing zapcore log field filtering.
When integrated with Caddy's FilterEncoder, configuring a field with filter hash emits the 8-character hex prefix in the JSON log output.

go 1.26 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-17 · ed25519:d91480838ac982c9