IT Forensics · Courts

Wie ist mit widersprüchlichen digitalen Spuren umzugehen?

Digitale Beweismittel sind nicht immer widerspruchsfrei. Ein Log kann einen Zeitpunkt nennen, während eine Datenbank einen anderen zeigt. Zwei Analyseprogramme können denselben Datensatz unterschiedlich interpretieren. Eine Datei kann in einem Backup vorhanden sein, im aktuellen Dateisystem aber fehlen.

Enquire without obligation

Solche Widersprüche sind kein Grund, die Untersuchung abzubrechen. Sie sind selbst ein Untersuchungsgegenstand. Entscheidend ist, ihre technische Ursache zu klären: unterschiedliche Zeitsemantik, Synchronisation, Parserfehler, beschädigte Daten, verschiedene Datenstände oder tatsächliche Inkonsistenzen.

Ein gutes Gutachten versteckt solche Punkte nicht. Es zeigt dem Gericht, welche Quellen übereinstimmen, welche nicht und wie sich dies auf die Beantwortung der Beweisfrage auswirkt.

The actual question of evidence

Welche Quelle hat bei Widersprüchen Vorrang?

Es gibt keine allgemeine Regel, dass ein bestimmtes Tool oder eine bestimmte Datenbank immer „richtiger“ ist. Bewertet werden Entstehungsmechanismus, Nähe zum Originalereignis, Integrität und Bestätigung durch unabhängige Spuren.

Bei zentralen Befunden prüfen wir erforderlichenfalls die Rohdaten oder verwenden eine zweite anerkannte Methode, um Parser- oder Darstellungsfehler auszuschließen.

Where the limits of what can be said lie

Wenn ein Widerspruch nicht auflösbar ist, muss die verbleibende Unsicherheit Teil des Ergebnisses sein.

Why LanCologne?

In the case of court-ordered investigations, it is not a matter of which analysis programme displays a match first. What matters is whether the question of evidence can be answered on a technical basis and whether that answer stands up to independent scrutiny.

We adopt an open-minded approach, document the origin of key findings and examine alternative technical explanations. The actual analysis is always carried out on a forensic copy or a dataset that has been securely preserved as evidence. Originals are not examined directly unless absolutely necessary. Where live procedures are technically necessary, any changes that may result from them are explicitly documented.

Depending on the research question, key findings are verified either using a second method appropriate to the subject matter or directly on the basis of the underlying raw data. The tools used for this purpose depend on the evidence and the research question. The key factors are the suitability, professional recognition and traceability of the method – not a product name.

Our report distinguishes between factual findings, technical assessments and remaining uncertainties. A negative finding is justified just as carefully as a positive one.

How we handle court-ordered assignments

How we work – from the court order to the response

1Check the terms of reference and the question of proof

We first check whether the matter falls within our area of expertise, what facts the court is basing its decision on, and whether the content or scope of the assignment is clear. If there is any doubt, the court will seek clarification. This is in accordance with Sections 404a and 407a of the Code of Civil Procedure (ZPO).

2Check for independence

Any reasons that might give rise to doubts as to impartiality are examined before the substantive investigation begins and, where appropriate, disclosed to the court.

3Record evidence clearly

Devices, data storage media, backups and files provided are identified and documented. The status at the time of the investigation is recorded.

4Ensuring data integrity

Where technically feasible, a forensic copy or image is created. Hash values and other integrity checks are used to ensure unambiguous identification. The original is retained for future verification.

5Derive test hypotheses from the question to be proven

We determine which evidence would support the alleged event, what contradictory findings are conceivable, and which alternative technical explanations need to be examined.

6Examine relevant data sources

Only those artefacts which have professional evidential value in relation to the issue in question are examined. Automatic matches are not accepted without verification.

7Independently validate findings

Findings relevant to the decision are – where necessary – cross-checked using a second recognised method, a different technical approach or directly against the raw data.

8Determining the limits of what can be stated

We explicitly examine what conclusions must not be drawn from the data. We identify missing data, possible deletions, technical limitations, incomplete extracts or contradictory evidence.

9Answer the question of proof clearly

The final conclusion is drawn from the documented findings. It is not stated in stronger terms than the data permit.

10Please attach the technical appendix

The main text remains accessible even to those without a background in digital forensics. The technical appendix contains the information required by an independent IT forensic expert to carry out a technical review or prepare a counter-report.

Legal framework

ZPO §§ 407a, 411 und 412. § 412 ZPO ermöglicht dem Gericht eine neue Begutachtung, wenn es ein Gutachten für ungenügend erachtet.

The expert provides the factual basis for the case. The legal assessment and the final evaluation of the evidence remain the responsibility of the court.

Frequently Asked Questions

Wie ist mit widersprüchlichen digitalen Spuren umzugehen?+
Digitale Beweismittel sind nicht immer widerspruchsfrei. Ein Log kann einen Zeitpunkt nennen, während eine Datenbank einen anderen zeigt. Zwei Analyseprogramme können denselben Datensatz unterschiedlich interpretieren.
How is such a technical investigation carried out in practice?+
How we work – from the court’s instruction to the response We first check whether the question falls within our area of expertise, what facts the court has taken as a basis, and whether the content or scope of the instruction is clear.
Does the result of the investigation provide clear evidence for the court?+
Wenn ein Widerspruch nicht auflösbar ist, muss die verbleibende Unsicherheit Teil des Ergebnisses sein.
Is there a legal basis for this?+
ZPO §§ 407a, 411 und 412. § 412 ZPO ermöglicht dem Gericht eine neue Begutachtung, wenn es ein Gutachten für ungenügend erachtet. Der Sachverständige liefert die fachliche Tatsachengrundlage.

LanCologne – IT Forensics for the Courts

Do you require an independent technical investigation into a matter of evidence for court proceedings? LanCologne examines digital evidence objectively, transparently and in a reproducible manner. We document both positive findings and the absence of evidence, as well as technical limitations, in such a way that the conclusions remain comprehensible to the court and verifiable by an independent IT forensic expert.

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