PRODUCT

Calculation, lineage and the sealed evidence package

This page shows DAHLIA's evidence chain stage by stage: data collection, calculation, lineage, version control and the evidence package.

Request a meetingInspect the sample package

EVIDENCE CHAIN

  1. 01Data collection
  2. 02Calculation
  3. 03Lineage
  4. 04Version control
  5. 05Evidence package

SYNTHETIC SAMPLE PACKAGE · Sample Plant · PERIOD March 2027 · bee6d1…937d

DATA COLLECTION

Measurement and source document

A measurement is recorded together with the document on which it rests.

  • Tabular data is imported as CSV; an ambiguous number format is not guessed.
  • The document digest is one of the seal's leaves.

SOURCE DOCUMENT

KAL-2027

application/pdf

DOCUMENT DIGESTc48216…ee83
SEALED MEASUREMENT3 records
  • edge meterSAYAC-NG-0118.400 Sm³
  • ERPKANTAR-0224,1 t
  • MESMES-HAT-122,4 t
Append-only ledger

CALCULATION

Methodology pack

The methodology pack is content-addressed JSON; a published version cannot be re-registered with different content.

  • The same input and the same version give the same number.
  • Every intermediate value is recorded.

METHODOLOGY PACK

cbam/aluminium-extrusion

VERSION
2027.01.1
LEGAL BASIS
3 sources

EXPRESSION ENGINE

A cyclic dependency or an unregistered operation is rejected at load time.

RECORDED STEPS5 steps
  1. 01Doğal gazın enerji karşılığı0,69552 TJ
  2. 02Doğrudan emisyonlar (yakıt yanması)39,018672 tCO₂e
  3. 03Biyet gömülü emisyon yoğunluğu3 tCO₂e/t
  4. 04Öncül madde emisyonları72,3 tCO₂e
  5. 05Toplam gömülü emisyon111,318672 tCO₂e

FROM RESULT TO SOURCE

Lineage

Each result is bound to its input set, its methodology pack and its source document.

  • The 4 leaves are joined under one seal root.
  • If a link is broken, the seal does not hold.

CALCULATION LEAVES

  • Methodology pack056d84…1a41
  • Input set313143…e9c9
  • Lineage4f29e3…c84a
  • Sources9d336d…4aad

SEAL ROOT

SEAL FORMAT 5

sha256:bee6d1edb484827bc0df35f81ea271bd30fc033537d8c9a9e04e4863482e937d

The seal root covers more than these leaves; the package header leaf and every document digest enter the same tree.

VERSION CONTROL

Bitemporal ledger

Event time and knowledge time are kept apart; a correction does not overwrite the earlier record.

  • The ledger accepts appends only; a record is not silently updated.
  • A past period is reproduced with that day's knowledge time.

TIME

  1. Event time1 March 2027 — 1 April 2027The period to which the measurement belongs.
  2. Knowledge time30 September 2027The moment as of which the package knows about that period.

Re-run

The calculation for a past period is re-run with that day's knowledge time.

30 September 2027 → 4,97 tCO₂e/t

PERIOD ARCHIVE

The evidence does not depend on the DAHLIA server

The period archive carries its own verifier; whoever holds the archive can verify its seal offline, without the DAHLIA server.

  • DAHLIA has two separate reference implementations, written in TypeScript and Python.
  • The golden vectors bind the two implementations to each other.

REFERENCE IMPLEMENTATIONS

TypeScript

packages/verify

Python

tools/verify_independent.py

Same seal rootbee6d1…937d

GOLDEN VECTORS

The two reference implementations agree byte for byte across the golden vectors, and both are written by DAHLIA.

Inspect the sample package

ROLES

Parties and the boundary of authority

  1. PRODUCES

    Installation operator

    Sealed evidence package

  2. VERIFIES

    Accredited verifier

01

Installation operator

Collects the data, runs the calculation and produces the evidence package.

02

Accredited verifier

Examines the evidence and forms an opinion within the scope of the grant.

03

Authorised CBAM declarant

Files the CBAM declaration; the registered operator may disclose verified information to them — Regulation (EU) 2023/956, Art. 6 and 10(7).

04

Auditor

Verifies the period archive's seal offline.

BOUNDARY

Functions outside the product's scope

  • DAHLIA does not reduce the calculation to a single number.

    Every calculation step is recorded in the lineage.

  • DAHLIA does not decide compliance.

    Embedded emissions based on actual data are verified by an accredited verifier — Regulation (EU) 2023/956, Art. 8(1).

  • DAHLIA does not produce a dashboard.

    DAHLIA prepares a sealed evidence package.

FAQ

Questions on the product

DAHLIA performs the calculation under the EU rules in force, ties every figure to its source document, methodology pack version and change history, and prepares the result as a sealed evidence package.

Founding customer package

The scope, pricing and application steps of the founding customer package are set out on its page.

Request a meetingReview the process steps