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Blockchain and Cryptocurrency Tracing Disputes: Digital Forensics Evidential Standards

By: Dr. Stephen Castell CITP CPhys FIMA MEWI MIoD
Accredited Member, Forensic Expert Witness Association, Los Angeles Chapter

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1. Introduction: ICT Professional Expert Witness Testimony

I recently acted as expert witness in a US State District Court trial in which the issue of identification and valuation of cryptocurrency assets (in particular Bitcoin holdings) featured, in connection with a disputed Contract Settlement.  I have previously written of the technical investigation aspects of disputes over crypto assets (such disputes having been christened by me Crypto Dragons), and of the evidential disclosure challenges involved (Castell, 2019).  In this trial, some notable differences appeared to me to emerge, as between UK and USA judicial standards and practices, in regard to the role, obligations, testimony, presentation and rigour of digital forensics expert findings.  I was surprised that such differences emerged, since, in the best of my knowledge and experience, there exists considerable harmony in mandated standards, and/or guidelines, for such matters, as between the UK and USA courts’ conduct, procedures and directions, in particular as regards the written opinions in reports produced and sworn by digital forensics expert witnesses (see 8. Background Reading).

It was also notable that I ‘attended’ the trial, and was examined and cross-examined, remotely, via BlueJeans, being based several thousand miles away from the court room.  All other participants, including the Judge, were physically local to the courtroom, within the US State concerned, but they, too, were ‘remotely present’, courtesy of BlueJeans, attending from nearby office or home locations.  Such is the new Coronavirus-driven ‘socially distanced’ administration of justice – which, for many reasons, not least savings in costs, I feel pretty sure is likely to continue, and indeed, develop further, ‘post-Covid’ (Hughes, 2020). 

Indeed, experience, talent and ability on the part of an expert witness smoothly to accommodate to, and work and present well by, ‘remote trial attendance’, is becoming a key CV attribute.  One of the most vigorous company start-up sectors is currently that of professional, and ‘knowledge and e-skills’, enterprises that are wholly ‘virtual’, and global (Dimoska, 2020; Lamm, Adams & Spira-Gutner, 2020).  Experts with practical competencies and track-records in these methods of remote working, and in ‘tele-provision’ of professional services, will likely be in demand in future.  ICT Professional consulting practices such as mine offer advice, guidance, planning, analysis and implementation in regard to these critically new ‘action at a distance’ professional, project and corporate management matters, if only because, over many years, it has become rather routine for us to carry out effective and comprehensive software, systems, data, operations, transactions and testing remotely, as a necessary ‘technical tele-examination’ methodology for forensic investigation purposes when preparing Expert Reports for litigation.

All in all, I suspect that ‘delivering remote digital forensics testimony’ may well be an increasingly relevant and timely subject for another separate article.

2. What Happened in the Case

I was retained very late in the day, with therefore limited instructions, viz, to provide a high-level critique of the opposing Expert’s Report.  That critique resulted in my opinion that the report was essentially unreliable.  This was because it neither identified the specific data elements upon which it was based, drawn from the case documents, nor set out the principles, software and detailed technical processes by which analyses of that evidence had been carried out, nor explained the rationale for arriving at the expert’s findings, conclusions and opinions, in any credible or rigorous way capable of being revisited or checked by another expert.

Furthermore, and to my surprise, at trial, the opposing attorney rather extensively repaired, enhanced, ‘decoded’ and clarified the contents of the opposing expert’s written report during long oral examination and re-examination of the opposing expert.  That significant degree of amplification and amendment of the expert evidence, as already committed in writing and sworn in an Expert’s Report, during the conduct of a trial, would in my experience be unlikely to happen in the English High Court.

The Judge in the US State District Court did not intervene, and indeed overruled objections by my instructing attorney to these repeated and relentless efforts by the opposing attorney to enhance, and add to, the already-filed opposing expert’s written evidence.  The net result, it seemed to me, was that the court in effect ended up with having available and in the record a wholly novel ‘Expert plus Attorney Report’, rather distinct from the – ‘techie’, unclear, and confusing – opposing expert’s original written evidence.

3. Features of the opposing expert’s presentation of evidence

The opposing Expert’s Report simply did not in my view meet established requisite standards for presentation of digital forensic expert evidence, under both US and UK guidelines, relevantly, for example:

Several best practices and guidelines developed by the Scientific Working Group on Digital Evidence, the UK Association of Chief Police Officers and the US National Institute of Justice have been developed to assist investigators in the collection and handling of digital evidence during forensic analysis … The key criteria … are …:

  • Under no circumstances should evidence be altered. …
  • Where a person finds it necessary to access original data held on a computer or storage medium, they must … give evidence to explain the actions taken …
  • An audit trail or record of all processes applied to computer-based electronic evidence should be created and preserved. A third party should be able to repeat these processes and replicate the results.
  • The person in charge of the investigation has the overall responsibility for ensuring that the law and the above principles are adhered to. …

(Neocleous, 2019).

Furthermore, whether or not presenting digital forensic expert evidence, in both the USA and the UK any expert witness has an overriding duty to the court, in particular to give an unbiased, clear and complete opinion to ‘a lay person – specifically the judge’ in a written Expert’s Report.  A recent English High Court judgment has provided a timely reminder of this standout principle:

The responsibility of experts in relation to their written evidence  A recent judgment from the Honourable Mr Justice Marcus Smith provides a cautionary tale for experts.  The judgment contains the following in section 13:

The last point that I make in relation to Professor Morgan’s evidence concerns less his oral evidence and more the written reports he submitted before the hearing and which he affirmed represented his expert opinion when he gave his evidence in-chief. …  An expert is responsible for his or her evidence, including the precise wording of any report submitted to the court under the name of that expert. In many cases, the expert will … receive assistance from the lawyers who have retained that expert. That … only serves to enhance the importance of the expert being entirely satisfied that his or her opinion is properly reflected in the report(s) submitted in that expert’s name. This is the duty of the expert …  An expert will be giving opinion evidence in relation to a subject-matter with which a lay person - specifically, in this case, the judge - will be unfamiliar. … It is incumbent on the expert not merely to present evidence that is technically correct, but that makes a fair presentation of the expert’s opinion

(Berney-Edwards, 2020; NEURIM vs GENERICS, [2020] EWHC 3270 (Pat)).

However, the opposing expert in my case seemed to consider (and his instructing attorney apparently endorsed) that his report was (only) ‘for another expert of similar technical expertise to read and deal with’, i.e. it was decidedly not designed or intended to assist the court’s understanding, by way of clear examination and illumination of complex technical matters ‘beyond the ken of the laity’.

Furthermore, the opposing expert’s assertions in oral examination were, confusingly, at one and the same time:

  • ‘It is simple for anyone, an average person, to trace cryptocurrency transactions using blockchain explorer software on’; and yet
  • ‘One can only make tracing inferences and opinions using specialist software, such as Chainalysis Reactor, plus heuristics, tagging and correlation software – in which software it takes much training and experience to become skilled’; and yet further
  • ‘In reality, no-one, no expert, can give an answer as to what crypto holdings are owned by whom; only the actual relevant owner can definitively do that’.

4. Analysis


‘Blockchain forensics’

There is an essential scientific point to be understood: a blockchain does not record personally identifiable ID information as to who owns or controls cryptocurrency wallets (this may be contrasted with bank accounts where regulated banks, as ‘Trusted Third Parties’, have to keep personally-identifiable KYC and AML records and data on account holders).  Convoluted inferences drawn from blockchain data, taken together with information discovered or implied ‘off-chain’, for example, may at best be correlated using personal heuristic methods, to arrive at what can only therefore be an expert’s subjective opinion.  Such cryptocurrency tracing analysis and reasoning is unlikely to be ‘objectively justifiable’, and may be fundamentally lacking in robust scientific rationale.

It is thus possible that there is a risk a court may conclude: what use, then, is such a ‘blockchain forensics’ Expert’s Report?  It becomes all the more important that any ‘blockchain forensics’ expert should communicate clearly the basis, analyses, findings and conclusions involved in arriving at that expert’s opinions, in good English and providing full details of the workings involved, and be honest and open about the scientific imprecision of the expert’s subjective inferences and correlations, both blockchain-derived, and through ‘off-chain’ heuristics and correlations (always remembering that ‘correlation does not equal causation’!).

Incidentally, as far as could be discerned within the text of the opposing expert’s report, the ‘blockchain forensics’ specialist in the case in which I was retained did not state any qualifications as a Chartered IT Professional (CITP) or as a Member of the Association for Computing Machinery (ACM,, nor being an accredited Forensics Practitioner as a Member of the US National Forensic Expert Witness Association (FEWA, https:/

Enhancement by attorney of an expert’s written evidence

Permitting an original written Expert’s Report which is, to the ‘laity’, arcane, confusing and unclear, as already served and filed with the court, to be enhanced, explained, clarified and expanded, with extensive input of additional novel illumination and material by and under the direction of the opposing attorney, to arrive at, effectively, a wholly new ‘Expert plus Attorney Report’ standing in the court record, can, it seems, be acceptable conduct in a US State District Court.  It may even be that this attorney-led extensive and material in-court elaboration of the already completed, written, signed, served and filed expert testimony, during oral examination at trial, is permitted and acceptable in US courts generally.

I of course defer respectfully to the law, and the accepted official practice, plus judicial leeway that may dynamically be granted in oral examinations, in US State District Courts.  In my experience the English High Court would however take a less than positive view of an expert witness’s failure to write and sign-off on a properly-founded, reasoned, clearly explained and completed Expert’s Report, in and of itself supposed to be assistive to the court, and of a barrister’s extensive attempts to repair a gross lack of detail, clarity or quality of, or other lacunae in, the filed expert evidence, ‘on the hoof’ during trial.  I suspect that such attempts would not normally be looked on favourably by an English High Court Judge.

Furthermore, in my understanding and experience it has been the standard rule/convention in the English Civil Procedure system for probably more than 25 years that the Expert’s Report, as written, signed and served, is automatically taken as that expert’s evidence-in-chief, already inviolate, ‘in the record’.  At trial, the expert witness is generally not, and does not need to be, examined-in-chief on his or her Expert’s Report.  Indeed, that is usually not done, so that no (or little) material ‘embroidery’ of the expert’s testimony happens during trial, the expert being simply and only cross-examined by opposing Counsel on what is already written, and must be relied upon, wholly within that Expert’s Report, as served.  The mandatory sworn Statement of Truth in every Expert’s Report makes it clear that: “the findings I have presented represent my true and complete professional analysis, conclusions and opinion”.

I have been involved in past cases where at trial an expert’s additional ‘explanations’ in oral testimony, where they start to stray significantly into areas and onto points that are not already in that expert’s written evidence, have been held to constitute materially new, or changed, evidence, analyses, findings, conclusions and/or opinions, following objection by opposing Counsel that these changes and elaborations are inadmissible.

Then, either the expert produces a supplemental, or correctional, report (if given leave by the court), so that the opposing party’s expert is reasonably able to consider this new, expanded and/or modified expert testimony carefully, and produce a rebuttal report thereon, if instructed to do so; or these attempted fluid amendments and enhancements to expert evidence are not permitted to continue, nor entered into the trial record, nor, therefore, relied upon or referred to by any Counsel in Closing Submissions.

It seems incidentally that there is in the Statute Law and Practice Directions applicable to that US State District Court no stipulation set down that an Expert’s Report must contain a Statement of Impartiality, and a Statement of Truth.  By contrast, these have long been standard strict requirements in both the Criminal and Civil Procedure Rules in the UK.

Nevertheless, in that State’s ‘Expert Witness Reports and Disclosures Rules’ there is set down:

If the expert is one who is retained or specially employed to provide testimony in the case [the expert’s] disclosure must be accompanied by a written report prepared and signed by the expert. This report must include a complete statement of the opinions to which the expert will testify and the grounds for those opinions; the information considered by the expert in forming those opinions; any exhibits to be used as part of the expert’s testimony; the qualifications of the expert, including a list of all publications authored in the preceding ten years; the compensation to be paid to the expert; and a list of any other cases in which the witness has testified in the preceding four years”.

This sounds to me intended distinctly not to permit the expert’s written opinion testimony to be enlarged, changed, clarified, simplified, enhanced or in any other way materially altered or ‘improved’ dynamically at trial through creative ‘leading’, or ‘massaging’, during oral examination of the written expert evidence by the expert’s instructing attorney.

Unsurprisingly, my own instructing attorney’s Closing Submission to the US State District Court succinctly included “The undisclosed ‘heuristics’ or ‘correlative’ or other methodologies said to have been employed by the expert, cannot be trusted by the Court”.

5. Learning Points

‘Blockchain forensics’ experts: you should be sure to give complete information as to the basis and processes of your investigations, and of the analyses you have carried out, in clear and complete detail so that anyone else may revisit what you have done, ‘check your work’ and form their own opinion thereon.  In particular, the forensic imaging of data and software is required to be carried out and disclosed.  If that means attaching 1,000s of pages of schedules of tracing data links/legs to your Expert’s Report, so be it (they can be provided on computer media, they do not have to be printed on paper).

Instructing Attorneys:  Be wary of accepting an Expert’s Report that is too ‘techie’, badly organised and obscure, and that requires much oral testimony to ‘unpack, explain and enhance’ at trial.  A good idea is perhaps, from the start of expert engagement, to have on board in the team a more experienced expert, with a reputation and track-record for explaining complex technical matters in clear English (my own experience, for example, is that my instructing Counsel’s view is usually: “Castell’s Reports can be summed up quite simply: ‘Reliably Clear and Compelling’”).

The Judiciary:  Please be aware of the fundamental truths of digital evidence (see for example 8.  Background Reading).  In particular, ICT lawyers are I understand likely to agree that it is not settled that standalone blockchain-derived tracing data of itself constitutes reliable evidence; furthermore, a cryptocurrency blockchain belongs to no-one, is unregulated, cannot be ‘sworn and examined’, and there is no responsible human witness who can speak for it (this can again be contrasted with Trusted Third Party regulated bank accounts and banks).  Finally, the tracing data and analyses of transactions presented via ‘blockchain forensics’ are derived and arise solely from and through the use of software (usually proprietary, new, and possibly buggy) as an intermediating technical tool, and are dependent on human skill and interpretation to derive results, make findings, form conclusions and arrive at opinions.

I also understand from informal discussion with digital forensics lawyers that it is arguably a legally open question as to whether ‘best evidence’, the blockchain data themselves, are actually capable of being properly adduced in court at all.

6. Conclusions

Blockchain forensics is simply part of well-understood computer and digital forensic investigation, and must, in the Expert’s Report, meet the same professional standards and guidelines of presentation and explanation of the full details of digital evidence: science, methodologies, processes, analyses, rationale, inferences, positioning and balance of opinion (clearly identifying where there is a measure of doubt, or alternative conclusions, and, if so, where and how much).  The standard protocols must be followed for forensic imaging, Chain of Custody, creating, preserving audit trails of processes used and recording in detail what has been done in the blockchain expert’s investigations.

The blockchain expert investigator’s technical knowledge, specialist examination software used (eg Chainalysis, blockchain explorer, graphing, heuristics, tagging, correlating etc), cryptocurrency personal judgement and experience etc are focused, intricate, deep and, to the ‘laity’, opaque.  Such techies should consider teaming up with more experienced expert witnesses to produce well-written good quality Expert’s Reports, in clear English, that meet court expectations and standards, and are a credit to and worthy of the reputation of ICT Professionals generally.

Despite the masses of data that arise in investigations of tracing cryptocurrency transactions and holdings, this is no excuse for sloppy expert witness work.  An expert witness’s overarching obligation is to explain technical matters clearly to the ‘laity’, and the Expert’s Report is not to be written to be understandable only by another similar expert (the implied posting of a warning notice ‘for blockchain and crypto-techies only’ is not to be entertained).

In summary:  The ‘blockchain forensics’ expert’s primary and overriding duty is to the court.  Presentation of any ICT Professional expert’s testimony must give the ‘normally expected’ full disclosure applicable to digital evidence.  This disclosure includes details and clear explanations of the science, methodologies, data and evidence used, and the processes, analyses, rationale, inferences, positioning and balance of opinion.  The ‘blockchain forensics’ expert’s written report must be in good English and with clear ‘flow’, visibility and presentation.  All of this must be presented together with proper identification of any software tools utilised, preservation of forensic imaging of data relied upon, audit trail of computer processes carried out, and Chain of Custody of all evidence and materials involved in the expert investigation.

7. References

Berney-Edwards, Simon (2020).  The responsibility of experts in relation to their written evidence.  Expert Witness Institute, 14 December.

Castell, Stephen (2019).  Authored by AI: Here Be Crypto Dragons: It’s All about the Evidence, Proclaims the CastellGhostWriteBot. Solicitors Journal, October, 43-45.  “Can you Tell If This Has Been Authored by a Robot? Would It Matter, Legally or Otherwise, If You Couldn’t? …  Are you crypto-friendly, or if not, at least crypto-aware?”.

Castell, Stephen (2019).  Blockchain vs Trust: The Fundamental Expert Dilemma.  EXPERT WITNESS JOURNAL, WINTER Edition.  “The internet is not a sue-able party. It has no intrinsic financial value, and ‘belongs’ to no-one. Since a Crypto Asset fundamentally consists of zeros and ones scratched on an internet-accessed blockchain, changes stored and processed, written into, a distributed ledger, it may seem futile, perhaps legally meaningless, to ascribe a tangible value to a decentralized blockchain, without any substantive, sue-able TTP responsible for or standing behind its integrity and security.
However, when Crypto Assets become the subject of disputes - Crypto Dragons, as I christened them, in a recent article in Solicitors Journal - the identification, location, and financial valuation of any Crypto Asset, access to it, holdings of it, and dealings and trading in it, will be critical”.

Dimoska, Elena (2020), November 9.  Top startup sectors likely to shape the post COVID-19 era.  “While the COVID-19 pandemic has shaken the world in an unprecedented way and brought many businesses to a halt, the enforced digitisation has accelerated the pace of various new and existing sectors. Although some of these sectors may lose their momentum after the pandemic as some of the most affected industries recover, many of the newly-created trends are expected to see long-term success. Consequently, we can already envisage a different post-COVID world ...

Hughes, Leon Hilliard “Hil” (2020), January 23.  What the Future Holds for Technology in the Courtroom.  “Cutting-edge breakthroughs in technology are changing the way lawyers argue cases and offering new ways for a case to carry real impact, in addition to making lawyers’ lives a little easier”.

Lamm, Julia; Adams, Rod; & Spira-Gutner, Alex (2020), 12 October.  The new virtual reality of recruiting.  “How to find, attract, and integrate talent in a world of hybrid work  When we look into the future of work, we know this much: it will never look like it did in the pre-COVID-19 world. … Most office workers (83%) want to work from home at least one day a week, and half of employers (55%) anticipate that most of their workers will do so long after COVID-19 ... But if recruits—and recruiters—are working remotely at least part of the time, traditional talent acquisition processes just won’t cut it for firms that want to attract the best talent ...”.

Neocleous, Elias (2019).  Admissibility of digital evidence in court. … Principles of digital evidence.  Elias Neocleous & Co LLC, July 2.

NEURIM vs GENERICS, [2020] EWHC 3270 (Pat)).

8. Background Reading

The Expert Witness’s Role, Duties, Obligations and Standards of Presentation of Expert Evidence

There is a general professional understanding of the requirement “that the expert must explain the basis of his opinion in order for it to have any value or weight at all”.  While this standard requirement is not given explicitly in the UK jurisdiction Civil or Criminal Procedure Rules, it has been affirmed in court judgments, for example in Kennedy (Appellant) v. Cordia (Services) LLP (Scotland) [2016] UKSC 6
“48. An expert must explain the basis of his or her evidence when it is not personal observation or sensation; mere assertion or “bare ipse dixit” carries little weight, as the Lord President (Cooper) famously stated in Davie v Magistrates of Edinburgh 1953 SC 34, 40. If anything, the suggestion that an unsubstantiated ipse dixit carries little weight is understated; in our view such evidence is worthless”.
Expert Evidence: Law and Practice 5th Edition, 31 May 2020, Sweet & Maxwell.  Tristram Hodgkinson, Mark James.  Series:  Litigation Library  Practice Area:  Litigation  ISBN:  9780414074354
Guidance for the instruction of experts in civil claims  Civil Justice Council  August 2014
…  13. Experts should take into account all material facts before them. Their reports should set out those facts and any literature or material on which they have relied in forming their opinions. …
56. Where tests of a scientific or technical nature have been carried out, experts should state:
a. the methodology used; and  b. by whom the tests were undertaken and under whose supervision, summarising their respective qualifications and experience.
57. … Experts must distinguish clearly between those facts that they know to be true and those facts which they assume.
58. … experts should express separate opinions on each hypothesis put forward. They should not express a view in favour of one or other disputed version of the facts unless, as a result of particular expertise and experience, they consider one set of facts as being improbable or less probable, in which case they may express that view and should give reasons for holding it.
59. If the mandatory summary of the range of opinion is based on published sources, experts should explain those sources and … state the qualifications of the originator(s) of the opinions from which they differ, particularly if such opinions represent a well-established school of thought.
60. Where there is no available source for the range of opinion, experts may need to express opinions on what they believe to be the range that other experts would arrive at if asked. In those circumstances, experts should make it clear that the range that they summarise is based on their own judgement and explain the basis of that judgement.  …
Role of the IT expert witness …  Stephen Castell.  Computer Law & Security Review, May 2003, 19(3):228–231.
Disputes over failed software implementation projects raise interlinked technical and legal issues which are complex, costly, and time-consuming to unravel — whatever the financial size of the claims and counterclaims, the facts and circumstances of the contract between the parties, or the conduct of the project and the management and software development methodologies which may have been used. This article explores the role of the expert witness in such disputes.

Best Practices and Guidelines on Digital Evidence

Digital Evidence and Forensics.  National Institute of Justice
ICT Experts and Forensics | Castell - ICT Patent Litigation  ...  The chosen expert has to inform and educate both the court, and the members of a jury, on many topics that are beyond the latter’s normal experience, and where the technology is likely to be foreign to them.  …  The Daubert Challenges ...  It is District Court Judges who … have been put in control of determining whether the expert testimony submitted is reliable enough for admission at trial ...  In December 2000 the US Congress codified the ‘Daubert standard’ for admitting expert testimony. The Federal Rules of Evidence, consistent with the Daubert trilogy, require that a District Court Judge acts as the ‘filter’ for all expert testimony, entrusting to the Judge assessment of whether the submitted testimony is reliably grounded and well-reasoned, and is not speculative …  This standard of reliability must be met by an expert testifying to any specialised knowledge, since neither Daubert nor the Federal Rules of Evidence restrict this ‘filtering’ function to scientific or technological expert evidence alone. ...
Digital Evidence and the U.S. Criminal Justice System
Computer Generated Evidence: The Impact of Computer Technology on the Traditional Rules of Evidence, 1989.  Daniel J. Lynch Honorable Judge, Ian Brenson
Electronic Evidence and Digital Forensics Testimony in Court, January 2008.  Fred Chris Smith, Erin Kenneally, University of California.  DOI: 10.1007/978-1-59745-577-0_8
Environmental Law Advisory, June 2003

Technical and Legal Reliability and Trustedness of Computer Evidence

Of particular recent and current note is the UK Bates v Post Office: Horizon Accounting System Trial Judgment:  https:/
Following this, the ‘presumption of reliability of computer evidence’ is being re-examined by the UK Ministry of Justice.  See eg https:/; and my foundational 1990 APPEAL Report and CLSR journal papers noting that ‘any trial using a computer should be a trial of the computer first’:
The APPEAL Report (Dr Stephen Castell, 1990, Eclipse Publications, ISBN 1-870771-03-6).  Still regarded by many in the field as definitive, and based on de-classified research carried out for H M Treasury on behalf of the five major Departments of
State of the UK Government, it exhaustively studied and reported on the legal
reliability and security of IT software, systems and media, and formulated the
still fundamental insight: Castell ’s First Dictum: “You cannot secure an ontologically
unreliable technology by use of an ontologically unreliable technology ”.

Recommendations for the probity of computer evidence requested by the Ministry of Justice, now published, Dec 16, 2020.
In August 2020, Alex Chalk MP, Parliamentary Under Secretary of State at the Ministry of Justice, invited Paul Marshall, Barrister, Cornerstone Barristers … to submit a paper to the Ministry of Justice on suggestions for improving the existing approach to the proof in court proceedings of computer-derived evidence. A working group was established to consider the issue. At the time the paper was submitted to the Ministry of Justice, in November 2020, it was explained that it was intended to publish the paper.  That paper, slightly edited, is now published: Paul Marshall, James Christie, Peter Bernard Ladkin, Bev Littlewood, Stephen Mason, Martin Newby, Jonathan Rogers, Harold Thimbleby and Martyn Thomas CBE, ‘Recommendations for the probity of computer evidence’, Digital Evidence and Electronic Signature Law Review 18 (2021), 18-25. https:/ ...
BOOK CHAPTER 6 The presumption that computers are ‘reliable’.  Stephen Mason, Daniel Seng. 2017, University of London Press, Institute of Advanced Legal Studies, pp. 101-192
Computer based testing – Bolls v. W. Scott Street, Sec'y of Va. Bd. of Bar Exmnrs., August 11, 2009, case no. 090915. Jonathan Bolls, Stephen Castell.  Computer Law & Security Review, Volume 29, Issue 4, August 2013, Pages 446-449.
The most significant change to law licensing in the United States is the recent reliance on computer-based testing for the bar exam in all of the fifty states. The following comment piece is meant to inform the computer and technology law community how the use of testing software must necessarily be accompanied by additional procedural protections and corrective processes that may not have existed previously. Chief among these is the availability of discovery of the item in question, namely in this case the essays in a computer-based bar exam, which constitutes evidence that is essential to vindicating one's rights when a software failure occurs. ...
Using the Forensic Systems Analysis methodology for expert opinion for online dispute resolution,  January 2004.  Stephen Castell.
Software on the Witness Stand: What Should It Take for Us to Trust It?  Sergey Bratus, Ashlyn Lembree, Anna Shubina

Castell, Stephen (1993): “Computers trusted, and found wanting”, Computer Law and Security Report, 9, July-August 1993, pp. 155-156.
Dr Stephen Castell, Report Correspondent, “A computer of the simplest kind’’, Computer Law and Security Report, 10, May-June 1994 (plus further references under its “FOOTNOTES”).
Castell, Stephen (1996): “Seeking after the truth in computer evidence: any proof of ATM fraud?”, THE COMPUTER BULLETIN, Volume 38, Issue 6, December 1996, Pages 17–19.
Anderson, Ross (1996): “Card Fraud and Computer Evidence: A closer look at the Munden case”, Information Security Bulletin 1, 1, October 1996. CHI Publishing Ltd, Leicestershire.
Code of practice and management guidelines for trusted third party services, S. Castell, INFOSEC Project Report S2101/02, 1993.

BERTIE, the First Electronic Barrister, Dr Stephen Castell, John Scannell and
Sheila Richardson, Law Society ’s Gazette, Wednesday 21 May 1980.
See also the ‘follow-up story’ article: HACKING OUT COMPUTER LEGISLATION, Stephen Castell.  UPDATE Magazine, Vol 2 No 1, 1989, pp. 10-13.

‘Blockchain forensics’ and cryptocurrency holdings and transactions tracing
Chainalysis is the blockchain analysis company. We provide compliance and investigation software to the world’s leading banks, businesses, and governments. Our experts in financial crime and blockchain analysis empower customers to derive insights they can act on.
Chainalysis Reactor Certification  Are you an investigator, compliance officer, analyst, or regulator? Learn to apply practical analytic techniques and perform blockchain analysis to derive actionable intelligence using Chainalysis Reactor.
Chainalysis cryptocurrency investigation software helps law enforcement and financial institutions identify and stop bad actors who are using cryptocurrencies for illicit activity such as fraud, extortion, and money laundering. With an intuitive graphical interface, …  Ratings/Reviews  This software hasn't been reviewed yet.
A few Promising additions to the Blockchain Ecosystem  By Faisal Khan  December 11, 2018
… The software also utilizes advanced tools like Pattern recognition & Machine learning algorithms to identify & categorize hundreds of Cryptocurrencies. Flow of funds in individual transactions can be traced via a direct link to Chainalysis Reactor … providing in-depth analysis on the origin of Cryptocurrency transactions. …

A Forensic Analysis of Blockchain Surveillance Companies  Kai Sedgwick Mar 5, 2019
Blockchain analysis is big business. The U.S. government alone has spent $6 million on transaction mapping tools, while cryptocurrency exchanges routinely partner with compliance companies that promise to track and trace the origin of customer funds. Hated by many bitcoiners, blockchain forensics is a controversial field with a plethora of players. ...

Crypto Crime Cartel: Erik Voorhees, ShapeShift and the Anarchists   NOVEMBER 2020  Jordan Atkins
In 2014, the U.S. Securities and Exchange Commission (SEC) charged ShapeShift founder Erik Voorhees with offering unregistered securities. He was forced to settle the charges, paying a fine and disgorgement on the millions of dollars he had illegally made from the offering. Later, in 2018, the Wall Street Journal published an investigation into digital asset intermediaries and was able to identify $90,000,000 of suspected criminal proceeds flowing through the businesses in a two-year period. ShapeShift was the largest recipient of these funds with a U.S. presence. …

Digital Forensics and Blockchain Originally published by BlockX Labs on June 3rd 2018  By: Laura Marissa Cullell Marketing & Operations Officer.  According to Auqib Hamid Lone, … it is of extreme importance to guarantee integrity, authenticity, and auditability of digital evidence as it moves along different levels of hierarchy in chain of custody ...

Annual ADFSL Conference on Digital Forensics, Security and Law 2011
Proceedings May 25th, Digital Forensics and the Law.  Karon N. Murff, Hugh E. Gardenier, Martha L. Gardenier, Sam Houston State University, Department of Computer Science.  Note on page 28/38:  3. … How persuasive any of these credentials would be is unknown to me. Some are likely going to establish enough expertise for the witness to qualify as an expert, but other, e.g., … certification by forensic software manufacturer, I’d want to know what that’s all about.”


. . .Continue to read rest of article (PDF).

Dr. Stephen Castell CITP CPhys FIMA MEWI MIoD, Chartered IT Professional, is Chairman of CASTELL Consulting. He is an internationally acknowledged independent computer expert who has been involved in a wide range of computer litigation over many years. He is an Accredited Member, Forensic Expert Witness Association, Los Angeles Chapter.

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