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What is the "Request for Sender Information Disclosure" to Identify the Perpetrator of the Post?


What is the

When there are postings on the internet that amount to defamation, causing damage to reputation and slander, it is essential to respond promptly, such as by seeking the assistance of a lawyer.

The actions that can be taken by enlisting the help of a lawyer for illegal posts on the internet are broadly twofold. They involve the removal of the said post and the identification of the perpetrator who made the post. In Japanese law, the process of requesting the disclosure of information of the sender, i.e., the perpetrator of the post, is called “Request for Sender Information Disclosure”.

The Request for Sender Information Disclosure is a request for information disclosure based on Article 4 of the Provider Liability Limitation Act (official name “Act on the Limitation of Liability for Damages of Specified Telecommunications Service Providers and the Right to Demand Disclosure of Identification Information of the Senders” enacted May 27, 2002). This is a process that seeks the disclosure of information (such as address, name, registered telephone number, etc.) about the sender, i.e., the perpetrator, who made expressions such as defamation on the internet, from site administrators who hold this information.

The Need to Identify the Perpetrator of the Post

In cases of online reputation damage, simply removing posts or articles often doesn’t resolve the problem. This is due to the person who made the post or article remains unaffected by the mere deletion.

Generally, when someone suffers defamation or slander due to illegal postings on the internet, the perpetrator who posted such articles or the perpetrator who posted them on sites like forums bears liability for damages to the victim under civil law, based on tort. “Damages” include costs incurred to identify the perpetrator (such as attorney fees) and, in the case of individuals, consolation money. Thus, victims of defamation or slander can demand compensation for damages from the perpetrator based on tort. Furthermore, depending on the content of the post, criminal offenses such as defamation or obstruction of business can be established. In this case, the perpetrator also incurs criminal liability.

However, articles on personal sites and other internet resources are often anonymous, and most postings on forums are also made anonymously. Typically, it is unclear who and where in the real world the perpetrator is. If the victim can’t identify the perpetrator, they can’t demand compensation for damages from the perpetrator.

Even if a post that defames or slanders is removed, there are many actual cases where the same information is repeatedly posted on different sites or forums. Removing individual posts turns into a game of whack-a-mole and doesn’t help the victim recover their damages.

By identifying the perpetrator and applying an appropriate penalty, you can effectively prevent recurrences of the incident and thus eliminate unnecessary costs. Therefore, Article 4 of the Provider Liability Limitation Act stipulates a means to enable the identification of the perpetrator, i.e., the sender, to support victims in the strongly anonymous environment of the internet.

What is the Provider Liability Limitation Law for disclosing information of the person who made the post?

What is the role of the Provider Liability Limitation Law?
The Provider Liability Limitation Law is a law that stipulates the responsibilities of internet service providers and bulletin board administrators when issues such as defamation or copyright infringement occur online. This law outlines the rights and scope of responsibility for providers in cases of harmful posts that violate laws or rights on the internet services they manage. In the context of the Provider Liability Limitation Law, the definition of “provider” isn’t confined to just Internet Service Providers (ISPs). It also includes entities such as administrators of bulletin board systems (BBS). In simpler terms, the law identifies “providers” as those entities that:

  • Involved in the distribution of information in the post
  • Not the person who made the post themselves

For example, if a defamatory post that insults an individual is made in the comment section of a blog on a website, the website administrator is not the person who made the post. In that sense, they are not the “culprit”. However, the website administrator can remove that post, and as a website administrator, they should have a duty to remove such illegal posts that can be considered as defamation and disclose the information they know about the perpetrator. The Provider Liability Limitation Law defines such parties as “providers”.

With the enforcement of the Provider Liability Limitation Law, it is stipulated that victims who have had defamatory posts made about them can request the disclosure of information about the person who made the post from the provider, such as the website administrator mentioned above.

(Provider Liability Limitation Law) Article 4 – Any person who claims that their rights have been infringed upon due to the circulation of information through specific telecommunications can request the disclosure of sender information related to the infringement of rights (name, address and other information that helps to identify the sender as defined by the Ministry of Internal Affairs and Communications) from a specific telecommunications service provider (hereinafter referred to as “the disclosure-related service provider”) who uses the specific telecommunications equipment for the specific telecommunications, only when the following conditions apply: 1. It is obvious that the requester’s rights have been violated by the circulation of the infringing information. 2. The sender information is necessary for the requester to exercise their right to claim damages or there is a legitimate reason for the requester to receive the disclosure of the sender information.

When can the person who made the post be identified?

The Provider Liability Limitation Law states that a requirement for requesting the disclosure of the culprit’s information is when it is clear that rights have been violated. This is generally referred to as the “obviousness of rights violation” requirement, and whether this requirement is met or not is often the point of contention.

There are several types of illegal activities on the Internet that can be subject to requests for the disclosure of sender information. Each type is explained below.

Determining the Viability of Defamation (Infringement of Honor Rights)

In cases of defamation (infringement of honor rights), a crucial point is whether there exists an objective fact that the victim’s personality, reputation, and credibility have been devalued due to the problematic writings. Furthermore, it is necessary that there are no circumstances suggesting the existence of causes for denying illegality, such as public interest, purpose of public benefit, or truthfulness. The freedom of expression, as guaranteed under Article 21 of the Constitution, naturally extends to online speech. It is sometimes deemed that the freedom of expression outweighs the illegality of the expression in question, hence rendering the expression non-illegal. Even if the expression in question lowers the social evaluation of a specific person, if it suggests a factual relationship to specific public interests (public interest), its sole purpose is to serve the public interest (public benefit), and the facts it suggests are true (truthfulness), or there is a reasonable reason to believe they are true (reasonable truthfulness), then defamation is not established.
Defamation is a typical situation where it is necessary to identify the person who wrote the post. Practically speaking, about half of the cases where the identification of the poster is sought result in allegations of defamation.

Existence of Privacy Infringement

In cases of privacy infringement, it is necessary that facts about the victim’s private life and undisclosed personal information are made public. Personal information such as name, address, date of birth, phone number, email address, as well as facts like having committed a crime in adolescence or being an illegitimate child, are generally considered private information that people do not want to be known to others. If photos or video images that can identify individuals are posted on the Internet, that can be considered an invasion of privacy.

Existence of Copyright Infringement

As for copyright infringement, only the copyright owner who has suffered rights infringement can request the disclosure of sender information. Therefore, as a prerequisite for requesting disclosure of sender information, the copyright owner must first prove they hold the copyright. While copyright typically belongs to the individual who created the text, photo, image, etc., there are cases where the rights are transferred to a company, as in the case of “work-for-hire”.
Moreover, a major point of contention is whether the act in question can be considered a copyright infringement. For instance, if the problematic act is a carbon copy (direct copy) of a copyrighted work, it’s likely to be deemed a copyright infringement (infringement of copyright law’s reproduction right, right of public transmission, etc.). Other disputes can involve the presence or absence of a license (usage right), whether changes to the copyrighted work constitute a copyright infringement, etc., based on the act in question. Therefore, it’s recommended to consult a lawyer with expertise on these issues.

Copyright infringement can also become an issue in cases of impersonation. For example, if an impersonator posts photos taken by the person they are impersonating onto an SNS like Instagram without permission, this could be considered copyright infringement. Therefore, in the process of identifying an impersonator, the existence of copyright infringement is also considered.

Existence of Infringement of Portrait Rights or Other Rights

The “rights” as referred to in the Provider Liability Limitation Law are not particularly limited, so it’s also possible to assert the infringement of “portrait rights” and other rights.
In the end, whether it’s honor rights, privacy rights, portrait rights, or other rights, if you can assert the infringement of some right, this requirement is considered fulfilled.

When there are “Justifiable Reasons” to Seek Identification of the Poster

The Provider Liability Limitation Law also states that there should be “justifiable reasons to receive disclosure of sender information”. This requirement signifies that the disclosure requester must have a rational necessity to obtain the sender information about the perpetrator.

Such requests for information disclosure are recognized as valid when there are legitimate reasons. Examples include:

  • It is necessary for the removal request to the sender.
  • It is necessary for the exercise of civil damage claims.
  • It is necessary for requests to restore honor, such as apology advertisements.
  • It is necessary for the exercise of injunction claims.
  • It is necessary to identify the person when taking legal measures such as criminal accusations.

In other words, when we aim to realize the purpose of the sender’s information disclosure request system, typically, the need to disclose information to make a damage claim against the offender is a typical case that is recognized. On the other hand, when disclosure is sought for improper purposes such as private sanctions, or when there is no need to take legal action, such as when compensation has already been paid, this is not recognized.

What is the ‘Sender Information’ Regarding Posts

When all the above requirements are met, you can receive disclosure of sender information. This enables identification of the offender who made the post.
In addition, the “information that contributes to the identification of the sender of the infringement information stipulated in Article 4, Paragraph 1 of the Law, which is stipulated by the Minister of Internal Affairs and Communications Ordinance”, includes the following seven items:

  • Sender’s name
  • Sender’s address
  • Sender’s email address
  • IP address related to the infringement information
  • Internet connection service user identification code from mobile phone terminals etc. related to infringement information
  • SIM card identification number related to infringement information
  • Year, month, day, and time (timestamp) when the infringement information was sent

Among these, the IP address is particularly noteworthy.

What is the IP Address of the Offender Who Made the Post

An IP address is an identifier that PCs and smartphones connected to the internet have, in principle, uniquely. When this IP address becomes clear, you can identify the provider that the offender who made the post used.
In the case of anonymous bulletin boards, etc., the offender who makes a post does not need to register his or her address or name to the site. Site operators do not identify who the offender who made the post is in the first place. Looking at it from the site operator’s perspective, they do not have a grasp of who the offender who made the post is. Therefore, even if you demand the site operator to disclose the name and address of the offender who made the post, the only response you get is “unknown”. This does not allow you to identify the offender.

However, even so, in most cases, site operators have a grasp of the IP address of the person who made the post.

How to Identify Offenders on Anonymous Bulletin Boards etc

  1. First, request the site operator of the anonymous bulletin board, etc., to disclose the IP address of the offender who made the post
  2. Request the provider, identified from the disclosed IP address, to disclose the address and name of the offender who made the post.

By following these steps, it is possible to identify the offender, even on anonymous bulletin boards, etc. I explain these procedures in detail in the article below.

Conclusion: Consult a Specialized Lawyer for requests to Disclose Sender Information based on Provider Liability Limitation Act

Just like deleting defamatory articles, requesting the disclosure of sender information involves complex and specialized procedures and is a highly specialized area. If you need to identify a poster, it can be resolved smoothly and quickly by consulting a lawyer familiar with internet issues.

Furthermore, identifying the offender who made the post has a certain time limit. Due to logs about the offender disappearing after a certain period of time. We recommend consulting a lawyer at the earliest possible stage.

Managing Attorney: Toki Kawase

The Editor in Chief: Managing Attorney: Toki Kawase

An expert in IT-related legal affairs in Japan who established MONOLITH LAW OFFICE and serves as its managing attorney. Formerly an IT engineer, he has been involved in the management of IT companies. Served as legal counsel to more than 100 companies, ranging from top-tier organizations to seed-stage Startups.

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