SSM-Clock Stamp – Anchoring & Daily Roll-Up (3)

Purpose. Create a public, day-level no-later-than time bound for a set of SSM-Clock Stamp lines without changing any past stamps. The anchor is a single ASCII digest you can publish anywhere.

What an anchor does (at a glance)

  • Select a UTC day: derive the day key from each stamp’s iso_utc → YYYY-MM-DD.
  • Canonically order that day’s stamps so everyone rebuilds the same sequence.
  • Join the lines literally and hash the joined ASCII to produce one digest:
    rollup_D = sha256( ascii(Stamp_1 "|" ... "|" Stamp_n) )
  • Publish rollup_D (and a small ASCII note). Its publication time supplies the public no-later-than bound for the included stamps.

Canonical selection (same-day set)

  • Day key (UTC): from iso_utc = "YYYY-MM-DDThh:mm:ssZ" take YYYY-MM-DD.
  • Inclusion: all stamps whose iso_utc share that UTC day.
  • Identity of a stamp: the entire line as recorded (base or with kv: tail):
    SSMCLOCK1|iso_utc|rasi_idx|theta_deg|sha256(file)|chain[|kv:...]

Canonical ordering (deterministic)
Sort by the tuple (ascending):

  1. iso_utc (string compare on fixed YYYY-MM-DDThh:mm:ssZ)
  2. stamp_core = "SSMCLOCK1|" + iso_utc + "|" + rasi_idx + "|" + theta_deg + "|" + sha256(file)
  3. chain
    This yields (Stamp_1, ..., Stamp_n).

Anchor digest (the roll-up)

  • Formula: rollup_D = sha256( ascii(Stamp_1 "|" ... "|" Stamp_n) )
  • Separator: literal | between full stamp lines; no leading/trailing |.
  • Empty set: if n = 0, define rollup_D = sha256( ascii("") ) and count = 0.
  • Output: lowercase 64-hex. (Anchor algo is fixed to sha256 in v1.3 for universal verifiability.)

Publish a tiny ASCII note (recommended)
Minimal fields (one per line):

SSM-Clock Stamp (SSM-CS) -- Daily Anchor
date=YYYY-MM-DD
count=<n>
rollup_algo=sha256
rollup_sha256=<64-hex>
sort=iso_utc,stamp_core,chain
source=<ledger|sidecars>

Optional clarity fields: from_iso_utc=<ISO_Z>, to_iso_utc=<ISO_Z>, publisher=<ascii>, anchor_id=<8-hex>.

Verify an anchor (observer, quick)

  1. Re-collect stamps for the UTC date.
  2. Canonical sort by (iso_utc, stamp_core, chain).
  3. Rebuild the joined string "Stamp_1|...|Stamp_n".
  4. Compute rollup_D' = sha256( ascii(joined) ).
  5. Pass if rollup_D' == rollup_sha256 and (if present) n == count.

Dual-source parity (should)
Compute the day’s anchor from ledger rows and independently from discovered sidecars. Expect parity: same rollup_D and count. Any difference → investigate for missing sidecars, stale ledger, or edits (use chain rewalk).

Operational cautions (summary)

  • UTC discipline: iso_utc is ...Z, seconds only; no subseconds.
  • Angle print: theta_deg must use exactly theta_prec digits (default 5) with IEEE-754 binary64 round-half-to-even; compare as strings.
  • Digests: lowercase 64-hex.
  • ASCII only: serialize with literal |, no extra spaces.
  • Leap second: 23:59:60 is forbidden.
  • Chain rewalk: use each row’s declared kv:chain_algo; seed chain_0 = "0"*64.
  • kv policy: ignore unknown keys; duplicates are invalid; float must be ieee75464.
  • Cadence: publish anchors regularly (e.g., daily) to bound backdating:
    max_backdating_window_sec <= anchor_period_sec.

Why it works
Local integrity and ordering hold via sha256(file) and chain_k. The public rollup_D is a cheap, composable claim: these lines existed no later than the publication time. No keys, servers, or blockchain required, and past stamps remain untouched.

Optional witnesses (nice-to-have)
Publish alongside the note:
witness_chain_tip=<64-hex> (last ledger tip of the day)
policy_sha256=<64-hex> (e.g., sha256(ascii(POLICY.txt|ALGO.txt|FORMAT.txt)))
These improve provenance without affecting verification.

Navigation
Back: SSM-Clock Stamp – Minimal Verifier Outline (2.10)
Next: SSM-Clock Stamp – Canonical Day & Selection (3.1)

Explore Further
https://github.com/OMPSHUNYAYA/Symbolic-Mathematical-Clock-Stamp