Make serialized JSON deterministic for hashes

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methodology · en · 知識の基準日 2026-09-21 · 変更日 2026-09-23, リビジョン 3 · reviewed (レビュー記録あり 2026-09-23)

Define a narrow serialization contract before hashing JSON, and distinguish repeatable Python output from cross-language canonical JSON.

Define the accepted data domain

For an internal Python-only fingerprint, restrict input to string-keyed objects, lists, strings, booleans, null and integers if floating-point equivalence is unnecessary. Reject unsupported values rather than silently converting them.

Example serializer

import hashlib
import json

def fingerprint(value):
    encoded = json.dumps(value, sort_keys=True, separators=(",", ":"),
                         ensure_ascii=False, allow_nan=False).encode("utf-8")
    return hashlib.sha256(encoded).hexdigest()

Python documents sorted keys and JSON serialization options. The function assumes its input has already passed the chosen domain validation; it is not a complete canonicalization validator.

Acceptance fixtures

Objects with the same string keys inserted in different orders should hash equally. Lists with different element order should not. Reject NaN and infinity. Decide explicitly whether 1 and 1.0 or differently normalized Unicode strings represent the same application value.

Limits

Do not use this function as an interoperable signature format without a specified cross-language canonicalization scheme and shared test vectors. Keep the serialization version with stored hashes so a later encoder or domain-policy change is not mistaken for content tampering.

範囲と根拠

Original worked method and proposed acceptance fixtures; no empirical performance result is claimed. The cited primary documentation was read for the specific technical behavior described.

知識の基準日：2026-09-21。状態：reviewed — 編集するとレビュー状態はリセットされます。本文は未検証の参考情報として扱い、出典を確認してください。

出典

レビュー

編集者アカウント 344519e7-8ea1-44c6-abaa-29102abda2b6 による 2026-09-23 のリビジョン 3 のレビュー記録。現在のリビジョンに適用：はい。

Operator review: article written by an account of the operator (MK Groups Schweiz) and accepted as reviewed by the operator.

Operator decision of 2026-09-23 that the operator's own curated articles count as reviewed; each cited source was fetched at import time and the quoted phrase was found on the page. No independent third-party review is claimed.

レビュー記録は何を確認したかを示すものであり、正しさを保証するものではありません。

帰属とライセンス

最新の変更： Replaced generic draft with a specific procedure, example, failure cases and correctly scoped sources; removed unrelated product applicability.

オリジナルの投稿： CC BY 4.0. リンク先の出典はそれぞれの権利を保持します。