Blockchain-Based Evidence Preservation: Opportunities and Concerns

By Zihui (Katt) Gu[+]

I.     Introduction

On September 3, 2018, the “Provisions of the Supreme People’s Court on Several Issues Concerning the Trial of Cases by Internet Courts” (hereinafter Provisions) was adopted at the 1747th session of the Judicial Committee of the Supreme People’s Court, which, for the first time, provides a comprehensive guidance on the trial process of the Internet Court from perspectives such as the scope of jurisdiction, mode of trial, acceptance of evidence, and rules of procedure.[1]  Undoubtedly, the promulgation of this regulation will play an important role in regulating the litigation activities of Internet Courts, protecting the legitimate rights and interests of parties and other litigants, and ensuring fair and efficient trials of cases.  As the most talked-about topic in 2017, blockchain technology has also been recognized in the Provisions as an eligible means to preserve evidence.  Subsection 6, Article 11 of the Provisions, stipulate that, “if the authenticity of electronic data submitted by the parties can be proved through electronic signature, trusted time stamp, hash value check, blockchain, and other tamper-proof, technical evidence collection and preservation method or through electronic evidence collection and preservation platform, the Internet court should confirm its authenticity.”[2]

Advanced technology such as trusted time stamps and blockchain are developing rapidly in recent years and have been gradually accepted by legal practitioners and applied in the judicial practice of various countries.  For example, the state of Arizona has passed an amendment early this year to update its Uniform Electronic Transactions Act, stating that “a record or contract that is secured through blockchain technology is considered to be in an electronic form and to be an electronic record” and are thus legally enforceable.[3]  Following these steps, Nevada,[4] Nebraska,[5] Ohio,[6] and New York[7] have introduced bills to clarify the legal status of blockchains and smart contracts in connection with electronic records and signatures, each featuring similar language.  In fact, prior to the promulgation of the Provisions, the Hangzhou Internet Court had made a judgment on the first blockchain evidence case, in which it recognized the eligibility and effectiveness of blockchain technology as an evidence preservation method.[8]

Nevertheless, there’s no one silver bullet.  So far the application of blockchain in judicial practice is limited to preservation of electronic data.  Prior to this step, the parties to the case still need to gather the evidence, and the reliability of evidence can be at stake if the methods, devices and types of technologies utilized in date collection is questionable.  In addition, the evidence-preservation methods are widely disparate as applied to different scenarios.  As a nascent technology blockchain may still be too immature to be applicable in some complex situations.  In such a case, resorting to traditional means is necessary.

The goal of this Article is to discuss the opportunities and concerns behind this novel evidence preservation technology.  Section II introduces the underlying mechanism and the advantages of blockchain system over the traditional notarization method.  Section III discusses the current legal status of a blockchain-based evidence preservation method while Section IV address concerns and suggests the directions for improvement.

II.     Background

Widely known as the technology that underlies the bitcoin network, blockchain technology, also called distributed ledger technology (DLT), has come into the public eye with the rise of cryptocurrency.[9]  A blockchain is “a distributed, shared, encrypted database that serves as an irreversible and incorruptible public repository of information.”[10]  In a blockchain system, the identities of users and integrity of data are protected through a key pair generated through asymmetrical cryptography: a public key, which can be disseminated widely, and a private key, which is kept secret to the owner.[11]  A key pair is mathematically linked: data encrypted with the public key can only be decrypted with its corresponding private key,[12] and vice versa – a characteristic that is fundamental to the operation of a blockchain system.[13]

Typically, a message (which contains data) is first converted into a hash and encrypted using the digital signature (also called “witness”) produced from the private key of the sender and the data the sender wishes to sign.  Then, the encrypted message is sent to the address of the entity receiving the funds along with the public key of the sender—similar to the name of the beneficiary on a check—which is a hashed version of recipient’s public key.  Upon receipt, the receiver decrypts the digital signature with the sender’s public key and compares the resulting hash to the hash of received message.  By doing so, it can be verified whether the message is in fact coming from the known sender and whether it has been tampered with by malicious third party.  As the ownership of a private key is bound to a certain user, a match of the two hash values means that message must be encrypted with the sender’s private key, and the sender cannot deny having sent the message.  In addition, since the signed message is an integral part of the digital signature, the signature will be invalidated if there is any change in the encrypted message, even just a single character.  Therefore, as long as the signature is recognized as valid, one can be assured that the data is not altered in the process of transmission.[14]

In a distributed system like blockchain, the message is broadcast to all of the computers connected to the network (known as “nodes”) rather than just the intended receiver.  Transaction data submitted to the network are organized into small groups called blocks that contain information of all transactions which occurred within a specific timeframe.  For new entries to be added to the blockchain, all of the nodes have to verify the integrity of records independently.  If a majority of nodes have approved, the block of transactions would be timestamped and included in the ledger with each new block referring to the block immediately before it, thereby forming a chain in linear and chronologic order.  One ground-breaking point of blockchain resides in the fact that the participating nodes in the system rely on the consensus algorithm, rather than a third-party organization or middleman confirming the validity or authenticity of logged information.  It means that no central authorities, such as banks or credit bureaus, are required to guarantee that no ill-intentioned individual is tampering with the data—an critical advancement that was often deemed by computer scientists in the early days as impossible to achieve.[15]  Just as Economist has once commented, “simply put, [blockchain] is a machine to create trust.”[16]

Since the blockchain has characteristics such as irreversibility, tamper-resistance, and decentralization, the data generated and stored on the blockchain is often considered to be authentic, reliable and credible.  In the context of judicial proceedings, the originality, integrity, and immutability of the evidence can be assumed by and large if it is preserved using blockchain technology, which can both ease the burden of proof for litigants and facilitate judges to make a judgement that is closer to the objective facts.

Usually, for a piece of evidence to be accepted by the Court, it should be conclusive and has to meet the following three requirements: legality, which means the investigators have to comply with the laws, rules and requirements when handling cases; objectivity, which means the fact or the content expressed in the evidence are true, not imaginary or fictional; and relevance, which means the evidence must be closely related to the facts to be proved and is capable of proving the evidence to be proved.[17]  In order to satisfy the three natures of evidence, traditional evidence preservation heavily relies on the notary public and the evidence captured by officers on site using methods such as video recording, photographing, and screenshot.[18]  The process of obtaining the evidence, or the process of producing the original evidence, is under the supervision and witness of the notary public, that is to say, the credibility of the original evidence is supported by the credit of the notary office and the notary public, and therefore the time cost and labor cost are high.[19]  By using blockchain to replace a part of the functions of the notary office, the process can be streamlined to just one click, saving manpower, materials, and financial resources while achieving greater fairness and efficiency.

III.     Analysis: Current Status of Blockchain-based Evidence Preservation

On June 28th, the Hangzhou Internet Court announced publicly its first-instance judgement on a dispute over the infringement of the right of dissemination through information network, which had instantly stolen all of the headlines and remained a trending topic in the last few months.[20]  In the case, the plaintiff, a company in Hangzhou, used the open-source software puppeteer and curl to crawl the infringing webpage and read the source code, then calculate the hash of the compressed package of the screenshot, source code, and call log to upload to the FACTOM blockchain and the bitcoin blockchain for submission to the court.[21]  When reviewing the evidence, the Court noted that, as a civil entity independent of the plaintiff, the third-party evidence preservation platform is qualified under state laws and regulations and it used highly-credible open source software to crawl the target webpage, which clearly reflects the source, generation, and transmission of the data.[22]  In the meantime, the integrity of the electronic data can also be ensured since it is preserved using blockchain technology conforming to relevant standards.[23]  Under the premise that the result of the hash value check is consistent and a complete chain of evidence can be formed, the electronic data can be used as the basis for the determination of copyright infringement, that is, where the defendant has infringed the distribution rights of the plaintiff.[24]

Although it may look like an ordinary intellectual property dispute at first sight, from the perspective of judicial precedent the case marks a huge breakthrough in the legal recognition of electronic records as it not only confirms the legal effect of blockchain data storage, but also explains the technical details and the requirement for blockchain-based evidence preservation in comprehensively.  Viewed from the angle of date generation and transmission, blockchain-based data storage actually contains two stages: first, use technical means to take screenshots and extract source code to generate the original data; second, upload the data to the public blockchain in the form of a hash value to form the new data.[25]  As in essence the digital data at issue is a form of electronic records stored using blockchain, whether it is admissible in a court of law as a fact to be proven should be based on the rules of reviewing electronic evidence.  Consequentially, in reference to the Article 8 of the “Electronic Signature Law of the People’s Republic of China”,[26] the Court determined that the following factors should be considered when examining the authenticity of digital data as evidence:[27]

1.  Review the authenticity of data sources, including the qualification of the third-party evidence preservation platform, the reliability of technical means for generating the electronic data, and the traceability of electronic data transmission;

2.  Review the reliability of electronic data storage, such as whether the electronic data is uploaded to a public blockchain, whether the content of one blockchain can validate another, and whether the block generation time is reasonable;

3.  Review the integrity of electronic data content, that is, compare the hash value of the compressed file with the data first uploaded to the blockchain;

4.  Review the degree of correlation between the electronic evidence and other evidence, so as to confirm the credibility and reliability of the evidence.

IV.     Recommendation

In light of the current status of judicial review, in order to improve the possibility of electronic evidence to be admitted by the court, legal practitioners should pay attention to the examination of the original carrier, substantive authenticity of the electronic evidence, choice of evidence the preservation platform, and introduction of an expert assessor.

         A.      Examination of the Original Carrier.

Article 10 of “Some Provisions of the Supreme People’s Court on Evidence in Civil Procedures” provides that “when producing evidence to the People’s court, the parties concerned shall submit the original document or original thing.”[28]  While Article 10 applies to the production of evidence in general, Article 22 of the Provisions clarifies the rules for collection of electronic evidence by the People’s Court, by requiring “the investigators who investigate upon and collect computer data or audio-visual materials such as sound recordings and visual recordings” to obtain the original carrier of the relevant data from the person under investigation.[29]  As a kind of intangible property, the formation, transmission, storage, and extraction of electronic data typically have to rely on a specific carrier, which, to some extent, act as the “original” of the electronic data.  For example, if one has taken a photo with his phone, the phone shall act as the carrier of the photo that is taken with it, and the photo on the phone shall be considered as the original although the person may generate multiple copies by importing the photo to his computers and other devices.  Therefore, when examining the authenticity of electronic evidence, it is necessary to look at the original carrier where the electronic evidence is generated or stored and compare it with the electronic evidence stored on blockchain whenever possible.

         B.      Substantive Authenticity of Electronic Evidence.

One weakness of blockchain-based evidence preservation is that it can only be used to prove that the evidence has not been tempered with after the date it was uploaded, but not that the documents submitted were not falsified or have not been altered before the time (that is, the substantive authenticity of the evidence).  In reviewing the trademark dispute between Fujian Septwolves Industry Co., Ltd and Chen Guozhen, the intermediate People’s Court of Wenzhou Municipality, Zhejiang Province, stated that submission of documents or electronic data from a computer terminal to trusted timestamping can only prove that the document or electronic data already exists and the content remains intact since it is time stamped.[30]  In other words, if the user has prepared relevant files in advance for submission, he can still obtain the trusted timestamp authentication certificate.  For the blockchain evidence to be admissible, the authenticity of the source of the electronic data must first be confirmed, whether through examination of the original or comprehensive consideration of all the evidence at hand.

         C.      Choice of Evidence Preservation Platforms.

The qualification of the third-party platform is an indispensable part of the court review when determining the admissibility of blockchain-based electronic evidence.  For example, in the copyright infringement claim between Hua Gai Company and Li Ming Zhi Jia,[31] the first-instance court, when denying the electronic evidence submitted by Hua Gai, pointed out that “first of all, whether the institution that issued the certificate is a legally established legal person or other organization and whether it has the qualifications for issuing such certificates are still unknown.  Huai Gai has not submitted relevant evidence to prove it.”  In fact, all the third-party platforms that have been recognized by the court so far have acquired certification of qualification from public security organs, network information security agencies, quality supervision agencies, or other public authorities.

         D.      Introduction of Expert Assessor.

With new technologies coming to the fore, it is difficult for the court, as a judicial organ, to keep up with the pace and have a deeper understanding of the basic principle of all technical means for preservation of evidence.  This, in certain cases, may lead to denial or negation of the effectiveness of electronic evidence due to the judge’s personal ignorance or prejudice against some technologies.  To help the court make a reasonable judgment on the authenticity of electronic evidence, the parties, depending on the actual circumstance of the cases, should be allowed to introduce expert assessors to assist them in explaining the technical problems.  Nevertheless, the court should properly review the qualification of the expert assessor before his word is admissible in a court of law, such as requiring the parties to submit professional qualification certificates and other materials to prove that the experts have expertise or experience in the specific issue involved.

V.     Conclusion

There is no doubt that the development and maturing of blockchain technology can make a big push in the adoption of electronic records and improving court efficiency.  Nevertheless, compared to the traditional notarization method, the popularization of blockchain-based evidence preservation still faces a major problem, that is, it lacks a unified and practical standard for implementation.  As we know, notarization has been extensively used in the judicial practices long before electronic records as a means to deter fraud, and a comprehensive set of standards including vetting, certifying and record-keeping were formed to assure that the documents are authentic and can be trusted.  Therefore, judicial officers are more familiar with the notarial procedures, and it is understandable that the legal effect of notarized documents are more likely to be recognized by the judges.  In order for the technology to truly benefit both the litigants and the court, a unified standard for blockchain-based electronic records should be established as soon as possible in accordance with the Provisions, including the key procedural and technical requirements.[32]

[+] Katt Gu is a researcher and advisor at APAC Blockchain Development Association, an organization under Taiwan university and Taiwan local government that aims to facilitate the development of blockchain technology and establishment of relevant legislation. Gu acquired her JD degree from University of Illinois Urbana-Champaign in 2017, and is currently a PhD student in informatics in UIUC, focusing on regulation of advanced technology and entrepreneurial law. She could be reached at

[1] Zuigao Renmin Fayuan Guanyu Hulianwang Fayuan Shenli Anjian Ruogan Wenti De Guiding (最高人民法院关于互联网法院审理案件若干问题的规定) [Provisions of the Supreme People’s Court on Several Issues Concerning the Trial of Cases by Internet Courts] (promulgated by the Judicial Comm. Sup. People’s Ct., Sept. 3, 2018, effective Sept. 7, 2018), CLI.3.4E7XGO3E(EN), (

[2] Id. (emphasis added).

[3] H.B. 2417, 53d Leg., 1st Reg. Sess. (Ariz. 2017), available at

[4] N.R.S. SB 398 § 1, available at

[5] L.B. 695 (Neb. 2018), available at

[6] H.B. 1357, 119th Reg. Sess. (Fla. 2018).

[7] S. 8858, 241 Leg. Sess. (N.Y. 2018).

[8] Hangzhou Huatai Yimei Wenhua Chuanmei Youxian Gongsi Su Shenzhenshi Daotong Keji Fazhan Youxian Gongsi (杭州华泰一媒文化传媒有限公司诉深圳市道同科技发展有限公司) [Hangzhou Huatai Yimei Culture Media Co., Ltd. v. Shenzhen Daotong Technology Development Co., Ltd.], (Hangzhou Int. People’s Ct., June 28, 2018) (China).

[9] See Satoshi Nakamoto, Bitcoin: A Peer-to-Peer Electronic Cash System, (2010), available at (Discussing that the Bitcoin Network is normally considered to be the very first system utilizing Blockchain Technology).

[10] Wright, Aaron and De Filippi, Primavera, Decentralized Blockchain Technology and the Rise of Lex Cryptographia, SSRN (March 10, 2015), or

[11] Matt Blumenthal, Encryption: Strengths and Weaknesses of Public-key Cryptography, Villanova Uni. (2007),

[12] Public key is calculated from and corresponds to a unique private key, but it is practically impossible to reverse engineer to get the private key from which it was generated.

[13] Blumenthal, supra note 11.

[14] John Prpić, Unpacking Blockchains, Collective Intelligence (2017),

[15] Lesile Lamport, Robert Shostak & Marshall Peacce, The Byzantine Generals Problem, 4 ACM Transactions on Programming Languages & Sys. 382, 382–401 (1982),

[16] The Trust Machine, Economist (Oct. 31, 2015),

[17] Zuigao Renmin Fayuan Guanyu Minshi Susong Zhengju De Ruogan Guiding (Yibei Xiuding) (最高人民法院关于民事诉讼证据的若干规定 [已被修订]) [Some Provisions of the Supreme People’s Court on Evidence in Civil Procedures [Revised]] (promulgated by the Judicial Comm. Sup. People’s Ct., Dec. 6, 2001, effective April 1, 2002), CLI.3.94HCM3L(EN), (

[18] Zhao Qionghua (赵琼花), Qukuailian Cunzheng De Yingxiang (区块链存证的影响) [The Impact of Blockchain-based Evidence Preservation], IPRDaily (Sept. 7, 2018),

[19] Id.

[20] Hangzhou Huatai Yimei Wenhua Chuanmei Youxian Gongsi Su Shenzhenshi Daotong Keji Fazhan Youxian Gongsi (杭州华泰一媒文化传媒有限公司诉深圳市道同科技发展有限公司) [Hangzhou Huatai Yimei Culture Media Co., Ltd. v. Shenzhen Daotong Technology Development Co., Ltd.], (Hangzhou Int. People’s Ct., June 28, 2018) (China).

[21] Id.

[22] Id.

[23] Id.

[24] Id.

[25] Lu Yichun (卢忆纯), Qukuailian Dianzi Cunzheng Falv Xiaoli De Rending (区块链电子存 证法律效力的认定) [Determine the legal effect of Blockchain-based Evidence Preservation], Zhichanli (知产力) (Aug. 8, 2018),

[26] Zhonghua Renmin Gongheguo Dianzi Qianming Fa (2015 XIuzheng) [Xianxing Youxiao] (中华人民共和国电子签名法(2015修正) [现行有效]) [Electronic Signature Law of the People’s Republic of China (2015Amendment) [Effective]] (promulgated by Nat’l People’s Cong., Aug. 28, 2004), CLI.1.3KQJDAC3(EN), (

[27] Hangzhou Huatai Yimei Wenhua Chuanmei Youxian Gongsi Su Shenzhenshi Daotong Keji Fazhan Youxian Gongsi (杭州华泰一媒文化传媒有限公司诉深圳市道同科技发展有限公司) [Hangzhou Huatai Yimei Culture Media Co., Ltd. v. Shenzhen Daotong Technology Development Co., Ltd.], (Hangzhou Int. People’s Ct., June 28, 2018) (China).

[28] Zuigao Renmin Fayuan Guanyu Minshi Susong Zhengju De Ruogan Guiding (Yibei Xiuding) (最高人民法院关于民事诉讼证据的若干规定 [已被修订]) [Some Provisions of the Supreme People’s Court on Evidence in Civil Procedures [Revised]] (promulgated by the Judicial Comm. Sup. People’s Ct., Dec. 6, 2001, effective April 1, 2002), CLI.3.94HCM3L(EN), (

[29] Id.

[30] Fujian Qipilang Shiye Gufen Youxian Gongsi Su Chen Guozhen (福建七匹狼实业股份有限公司诉陈国珍 [Fujian Seven Wolves Indurstrial Co., Ltd v. Chen Guozhen], (Zhejiang Sup. People’s Ct., Aug. 17, 2015) (China).

[31] Huagai Gongsu Su Liming Zhijia (华盖公司诉黎明之家公司) [Huagai Company v. Liming Zhijia], (Beijing Intell. Prop. Ct.) (China).

[32] Luwei (鲁伟), Zuigao Fayuan Chutai Hulianwang Fayuan Sifa Jieshi Qukuailian Cunzheng, Kexin Shijianchuo Huo Chubu Renke (最高法院出台互联网法院司法解释, 区块链存证、可信时间戳获初步认可) [Supreme Court issued Judicial Interpretation on Internet Court, Blockchai-based evidence preservation and trusted time stamp was initially recognized], Caijing (财经) (Sept. 9, 2018),