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Blockchain and Evidence Law

Digital legal evidence is an evolving field. As always with law and technology the law is doing its best to keep up with the technological advancements. It is becoming more and more challenging to prove the origin, integrity, and authenticity of a digital evidence.

Blockchain technology can provide the solutions to some of these challenges. Using the key attributes of the blockchain, specifically the fact that the information in the blockchain is encrypted, immutable, and secure can lead to a better alignment between current evidence law and the reality of our digital life.

Black's Law Dictionary defines Evidence Law or Rules of Evidence as “the total of the principles and rules that govern the presentation of evidence in a legal matter.” In other words, evidence rules determine the means by which one can prove a fact in a legal proceeding.

Whilst innovation and technology advancements are growing at an exponential pace and influencing an ever-growing portion of the world population, law is trying its best to keep up. Law in general is slow to react to changes in society and ever since the information age revolution it is getting harder and harder.

Evidence law in the digital age is no different. Most law systems are still clinging to the “Best Evidence Rule”- a rule giving a superior evidentiary status to an original document over a copy. Trying to apply this rule to digital evidence is proving extremely difficult. In addition, it is becoming more and more challenging to prove the origin, integrity, and authenticity of a digital evidence.

Some of these problems can be solved by applying and utilizing blockchain technology, but before we dive into the possible solutions a short primer on blockchain technology is due.

The Blockchain

Blockchain was made famous by its most known use case – cryptocurrencies. Although cryptocurrencies, like Bitcoin, Ethereum, Litecoin, and Monero, to name a few of the more known currencies (there are currently approximately 2,000 cryptocurrencies) get most of the news coverage, it is other use cases of the same underlying technology that can be applied to make a difference in the realm of digital evidence.

The formal definition of the blockchain is an immutable or incorruptible distributed ledger that records transactions. In other words, the blockchain is a digital database that is being hosted in its entirety on each of the computers connected to the blockchain network (each end point is called a node), each node validated the information on the database independently (no centralized authority) and the database is updated only if a consensus of the all of the nodes is reached. Such validated transactions are written into the database almost in real-time and is timestamped.

As the name may suggest, blockchain is indeed a chain of blocks. Each block contains a list of validated transactions and a link to the pervious block, thus creating a chronological chain of validated transactions.

Encryption, Hashing, Digital Signatures and the Blockchain

Public key encryption allows you to communicate messages over a public network, encrypting the content of the message, allowing only the recipient of the message to decrypt ant read the content of the message. This is done by generating a pair of keys - a public one that is used to encrypt the message by anyone and a private key used to decrypt the message (as it names suggests, kept private). The most famous scheme of public key encryption is called RSA and is the underlying technology of SSL certificates and HTTPS browsing.

Digital signature is another application of public key encryption, by signing the content of the message with a digital signature scheme you can achieve three important attributes: 1) authentication of the identity of the sender, 2) integrity of the content of the message (same as in any public key encryption scheme), and 3) non-repudiation – that is, the signer of the message cannot retract or deny the fact that he is the one who signed and sent the message at a given time.

Hash functions are one-way algorithms that can take any string of information, no matter what size and produce a new string of information with a short-predefined length (In the Bitcoin blockchain hashes are 256 bits, or 64 characters). The same input will always produce the same output, but you cannot infer the original input from the output. In addition, if you change even one character in the original input, you will get a different hash output. Hash functions have many uses in the cryptography world, the most important for the blockchain is in validating the integrity of a file.

These cryptographic attributes of blockchain are providing us with an affordable solution to proving the ownership of digital assets by putting the hash of the signature of a file's hash in the blockchain. Thus, associating the owner of the private key used to sign the file with the file itself.

This action will allow us to provide proof of existence. Since all transactions on the blockchain are time stamped once on the blockchain, we can ascertain that the file associated with it was in existence at that specific time.

Once hashed, signed, and written onto the blockchain, we can also prove the integrity of the data, making sure it is tamper-proof and immutable. We can even authenticate a recipient of an email message and validate the time of receipt.

The use cases in the world of evidence and digital evidence are endless. The most prominent ones are using the blockchain as a notary service. A few notable examples are: silentnotery, blocknotery and, or utilizing the technology as part of the service of process as a recent POC by integra ledger and ServeManger, avoiding the need of serving the courts with affidavits regarding servicing, intellectual rights management relating to proof of first or genuine use or evidence of creatorship, and even verifying the chain of custody in criminal cases.

Some jurisdictions are already trying to catch up and utilize this technology. A recent ruling by the Hangzhou city Chinese internet court has ruled that evidence authenticated with blockchain technology can be presented in legal disputes (this case was about intellectual rights infringement).

California's Uniform Electronic Transactions Act (UETA), Civil Code section 1633.1. already supports the public key cryptographic signatures as an indicator of authenticity.

And Vermont passed H.868 (Act 157) stating that: “A digital record electronically registered in a blockchain shall be self-authenticating pursuant to Vermont Rule of Evidence.”

Although the legal framework around blockchain technology in general is still a work in progress and the impact of this disruptive technology on evidence law is not set in stone yet, there is no question that the key attributes of the blockchain technology as discussed above, will allow for better alignment between our ever-evolving digital information age and the arcane world of 19th century evidence world.

I believe lawyers should position themselves at the forefront of this technological drive forward.


About the Author Adv. Nimrod Tauber is a founding partner and head of the Cyber & Internet Law and Corporate departments of the Aloni-Davidov Tauber Law firm.

As head of the Cyber & Internet Law department, Adv. Tauber acquired a wide range of expertise tailored to meet the needs of the firm client’s in this ever evolving and far reaching legal field. He has a strong technological and business background with deep understanding of the cybersecurity, online commerce, marketing and advertisement Industries.

Adv. Tauber graduated from the Herzliya Interdisciplinary Centre (LL.B. Law + B.A. in Government), and is a member of the Israeli Bar Association’s “Cyber, Internet and new media” and “Privacy” committees.

Adv. Tauber is also a member of the International Association of Privacy Professionals (“IAPP”). In addition, Adv. Tauber is certified by the Israeli Standards Institution as a lead auditor of the two main information and cyber security standards - ISO 72001 and ISO 27302. And is currently pursuing a Master's degree of Cybersecurity, from Brown University.

Adv. Tauber is an Instructor with Information and Cyber Security Division of the Israel Military Industries Academy for Advanced Security & Anti-Terror Training.

Adv. Tauber is the proud father of four lovely children a retired diving instructor and an active open-water swimmer.

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