Procurator-General of the People's Procuratorate of Xihu District, Hangzhou: Using blockchain technology to extract and review criminal electronic data

Author: Xihu District, Hangzhou, Zhejiang Province, People's Procuratorate Attorney Chen Pingxiang Source: Procuratorial Daily Editor's Note: The original title is "block chain using technology to extract and review the criminal electronic data"

In June 2018, the first case of the blockchain deposit in the country was pronounced by the Hangzhou Internet Court. The court supported the plaintiff's use of the blockchain as the method of deposit and the corresponding infringement facts. In September 2018, the judicial blockchain of the Hangzhou Internet Court was officially put into operation. Article 11 (2) of the Supreme People's Court of the same month promulgated the Provisions on Several Issues Concerning Internet Court Cases:

“Electronic data submitted by the parties can prove their authenticity through electronic signature, trusted time stamp, hash value verification, blockchain and other evidence collection, fixed and tamper-proof technical means or through electronic forensic evidence platform certification. The Internet court should confirm."

It can be seen that both the Hangzhou Internet Court and the Supreme People's Court have recognized the attributes of the blockchain “not tamperable” and “unforgeable”. At present, in the process of handling criminal cases, there are problems in the process of electronic data extraction and collection, such as non-standardization, unsafe storage and circulation, and difficulty in reviewing and judging. The blockchain technology uses a hash function to make the data mutually validate each other, form a data chain, and store the data in each node to prevent private tampering, which can effectively guarantee the authenticity and integrity of the electronic data. Compared with the traditional methods of electronic data forensics and deposit, the application of blockchain extraction and collection of electronic evidence has the following three characteristics and advantages:

Intelligent electronic data extraction . There are two types of electronic data sources for criminal cases: one is electronic data generated by investigative activities, such as simultaneous recording and recording of interrogation and search, and recovery of electronic data in hard disks and mobile phones. The second is the electronic data generated during the incident, such as on-site monitoring, WeChat chat records, e-mail, transfer transaction records, and so on. For the first type of electronic data, the blockchain technology can automatically check the integrity of the electronic data at the same time as the electronic data is generated, and save the hash value to prevent tampering with the evidence. The forensic officer records the transcript, writes the description, and signs and seals to "self-certify innocence." For the second type of electronic data, because the authenticity and integrity of the electronic data before it is uploaded to the blockchain cannot be proved by the blockchain itself, the blockchain technology needs to simultaneously record the forensic process and upload the block together with the forensic result. The chain performs an integrity check. Therefore, before the data is uplink, it is still necessary to use artificial intelligence and other technologies to automatically record and assist the legality of the forensic process, such as the identification of the investigator, the collection of object information, the location of the latitude and longitude of the site, the time and process of the forensics, and whether the process is complete. Equivalent to the addition of an "electronic witness" to provide substantive review materials such as operational logs, verification methods, and environmental parameters for the subsequent judicial review of electronic data.

Decentralization of electronic data storage . A copy of the electronic data is scattered by the blockchain and stored on each node on the network. Any node tampering and loss will not affect the integrity and security of the data. In criminal cases, the evidence and transcripts of the case are transferred (and repeated) between the “public security-procedure-court”, allowing evidence and transcripts to be transferred in their respective systems (online or offline), and the parties can openly access a common chain. Each system can verify the received electronic data through the uplink information, and can also include judicial identification, price evaluation, notarization and other departments.

Moreover, the more organizations that store data on the blockchain, the more difficult and costly the tampering and deletion of the blockchain, and the higher the security of the blockchain. Because the uplink information of electronic data is uniformly preserved, under the constraint of the blockchain consensus mechanism, all the additions, deletions, and modifications need to be agreed and recorded by each node, and no single institution can tamper with the electronic data alone. Realize the effect of “extracting and unifying storage” of electronic data. It should be noted that the block chain mainly stores the hash value of the electronic data instead of the electronic data itself, because the hash algorithm has irreversible characteristics, and other non-handling mechanisms cannot obtain the hash value on the blockchain copy. The original text of the evidence is calculated in reverse, thus taking into account confidentiality and irreparable modification.

The electronic data review is substantive . The blockchain technology does not require professional operation. The blockchain automatically calculates the hash value of the electronic data, and uploads the blockchain together with the forensic elements such as time, location, forensic information, and equipment number. The calculation and the winding process are free of labor. Intervention, eliminating the possibility of forgery and tampering. When using blockchain technology to review electronic data, prosecutors and judges only need to install an electronic data verification platform, and put the electronic data into the verification platform for viewing. Whether the electronic data is on the chain, whether the data is true or not, is clear at a glance.

Further, the verification platform also reads the forensic information saved when the electronic data is wound up, and intelligently generates an analysis report containing various forensic elements for the prosecutor and the judge to review the legality and relevance of the electronic data. Prosecutors and judges can use the report to understand the time and location (latitude and longitude) of the corresponding electronic data generation, the extraction of personnel information, equipment number, electronic data format and size, etc., and compare and discern other evidences in the case. Make a simple and effective judgment on whether or not to accept the letter.

Blockchain technology is just like DNA technology. In the future, it will definitely provide great support for judicial proof, but it should not be too "myth". It should still be set with strict and strict rules of evidence. When reviewing the electronic data extracted by the application of blockchain technology, we still need to pay attention to the following two aspects: First, the originality of the electronic data before the uplink. Before the data is attached to the blockchain, the authenticity and integrity of the data in this time period cannot be proved by the blockchain itself. It is still necessary to combine the evidence of forensics, the transcript of the inquest, the audio and video recordings of the forensics process, and comprehensive analysis. Determine whether the electronic data is tampering or contaminated before being wound up. The second is the legality of the collection and extraction process. The electronic data extracted by the blockchain technology does not of course have the legality of the procedure. It is still necessary to examine whether the elements of the evidence collection subject, the evidence collection procedure, the location of the evidence are legal, etc. according to the requirements of the Criminal Procedure Law, and prevent the illegal evidence from becoming the basis for the final decision.