Important legal matters concerning the introduction of sender authentication at the receiving side by an ISP

Transcription

1 Important legal matters concerning the introduction of sender authentication at the receiving side by an ISP Telecommunications Consumer Policy Division, Telecommunications Bureau, Ministry of Internal Affairs and Communications

2 Filtering process by means of sender authentication technology ISP s mail server (receiving side) Sender Authenticating sender s domain Inserting the result of the authen- -tication in the mail Filtering according to the results of the authenti- -cation Mail server (sending side) Receiver 1

3 Points at issue The legal definition of sender authentication Sender authentication technologies, both DKIM and SPF, are legally interpreted as checking a sender s domain for mail receipt and taking certain measures despite technical differences. We now need to examine, in terms of the Telecommunication Business Law, whether there is a problem with an action by which a mail server administrator mechanically authenticates the sender s domain for mail receipt and inserts the results of authentication contrary to the will of the person concerned with communication for the purpose of filtering (hereinafter referred to in this report as domain authenticating and result inserting ). More specifically, the points at issue are whether domain authenticating and result inserting corresponds to a violation of the secrecy of communications stipulated in article 4 of the law, and whether domain authenticating and result inserting corresponds to unfair discrimination in providing telecommunications services stipulated in article 6 of the law. 2

4 What constitutes a violation of communications secrecy? Telecommunication Business Law Article 4. (Protection of Secrecy) (1) The secrecy of communications being handled by a telecommunications carrier shall not be violated. 1.What constitutes secrecy of communications? Secrecy of communications consists of not only 1) the content of individual communications, but also 2) components of individual communications such as where the persons concerned with communications live, who they are, when they communicated, where they communicated. The sender s domain for each mail is a communicative channel for information and then, it falls within the individual communications category and has to be protected as part of the secrecy of communications. 2.What constitutes a violation? A violation of the secrecy of communications includes using individual communications contrary to the intention of the sender or the receiver. Again, sender authentication technologies are legally interpreted as checking a sender s domain for mail receipt and taking certain measures Undertaking domain authenticating and result inserting violates the secrecy of communications. 3

5 Assessment of whether circumstances warrant action being taken to preclude wrong-doing. (1) Point at issue Although undertaking domain authenticating and result inserting violates the secrecy of communications, it could be justified if certain factors are considered such as selfprotection, emergency actions depending on necessity, and actions committed in the pursuit of lawful business. 1) Self-protection or Emergency Action depending on necessity Sender authentication is generally undertaken to prevent mail service disruptions caused by huge amounts of mail being sent. This however does not necessarily meet the criteria for imminent formation of self-protection or urgency for formation of emergency actions depending on necessity. Generally self-protection or emergency actions depending on necessity would not be warranted. 4

6 Assessment of whether circumstances warrant action being taken to preclude wrong-doing. (2) 2) Action committed in the pursuit of lawful business Requirements for action committed in the pursuit of lawful business are (1) necessity and justification in taking such actions, and (2) validity of the measures taken. (1) Necessity and justification for domain authenticating and result inserting Considering: Almost all mails with the sender s information camouflaged are spam mails. Almost all spam mails are sent with the sender s information camouflaged. As spam mails are sent for advertising purposes, they are reasonably assumed to be sent to numerous addresses simultaneously. Then, mails with the sender s domain camouflaged are presumed to be sent to numerous addresses simultaneously. Domain authenticating and result inserting can be seen as an action to prevent such failure of the mail service as delay in mail service caused by large amounts of mail being sent, which means that the necessity and justification for domain authentication and result inserting can be accepted. 5

7 Assessment of whether circumstances warrant action being taken to preclude wrong-doing. (3) (2) Validity of means Necessary minimum violation: The component of communications violated by authenticating sender s domain is simply the channel of telecommunication, so domain authenticating and result inserting does not overstep the action required for the purpose (filtering with the result of the authentication) of achievement. Non-existence of alternative measures: Even if other anti-spam measures such as outbound port 25 blocking and S/MIME were introduced, these technologies would not necessarily be valid in preventing the transmission of mail with the sender s domain camouflaged. The validity of means can be accepted in domain authenticating and result inserting. Domain authenticating and result inserting can be judged to be an action committed in the pursuit of lawful business. (=> Circumstances precluding wrong-doing) 6

8 What constitutes unfair discrimination in providing telecommunication services Telecommunication Business Law Article 6. (Fairness in Use) Any telecommunications carrier shall not discriminate unfairly in providing telecommunications services. Is domain authenticating and result inserting equated with unfair discrimination in providing telecommunications services? Because domain authenticating and result inserting is judged to be a justified business action in relation a the violation of the secrecy of communication, it is not seen as being unfair to use. Undertaking domain authenticating and result inserting is not seen as being a violation of article 6 of the Telecommunications Business Law. 7

9 Filtering process by means of sender authentication technology ISP s mail server (receiving side) Sender Mail server (sending side) Authenticating sender s domain Inserting the result of the authen- -tication in the mail Filtering according to the results of the authenti- -cation Receive r Receiver s agreement or circumstances precluding wrong-doing Receiver s agreement is demanded 8

10 Does anti-spam filtering violate the secrecy of communications? Telecommunications Business Law Article 4. (Protection of Secrecy) (1) The secrecy of communications being handled by a telecommunications carrier shall not be violated. Is the secrecy of communications violated by carrying out filtering off received mail according to data such as sender authentication result inserted to the mail (hereinafter referred to in this report as filtering )? Filtering is an action by which the mail server administrator assesses the secrecy of certain communications due to a spam-judging standard decided in advance and takes such measures as blocking or isolating spam mails regardless of the intention of the person concerned with the communication. By carrying out filtering, the secrecy of communications is generally violated contrary to the intentions of the person concerned with the communication. Unless the receiver agrees to introduce the filtering service, undertaking filtering violates the secrecy of communications. 9

11 How ISPs should obtain the consent of users to introduce the filtering service A) Introduction of filtering service following user s application The consent of users to introduce the filtering service is given. B) Introduction of filtering service without user s application Having users abandon the advantages of secrecy of communication by a prior comprehensive agreement in an article, etc. is not permitted, because such agreement is not suitable in an article and the range of such an agreement is obscure. However, under the conditions set out below, ISPs are considered to have obtained the user s consent for the introduction of filtering service without the user s application. 1. Users are allowed to freely withdraw from the filtering service at any time. 2. Regardless of the existence of an agreement for introduction of the filtering service, other provision conditions are the same.(*1) 3. The object and the range of "the secrecy of communication" violated by the filtering service are clearly defined. 4. Ordinary people are presumed to have consented to the introduction. (Corroboration by reliable data is required. (*2)) 5. Sufficient explanation on the filtering service for users to be provided in advance. (in accordance with the important matter explanation specified in Article 26 of the Telecommunications Business Law) *1 Providing the filtering service with a reasonable charge is acceptable. *2 For example, questionnaire by random sampling of users. 10

12 Conclusion Sender authentication technology is regarded as an effective countermeasure against spam. On the contrary, undertaking sender authentication on the receiving side violates the Telecommunications Business Law, especially, secrecy of communications and prohibition of unfair discrimination in providing telecommunications services. However, considered as actions committed in the pursuit of lawful business, undertaking sender authentication on the receiving side is legally acceptable.( ) Therefore, sender authentication is recommended, and its promotion is advisable. ( ) To introduce filtering according to the results of the authentication, each user s consent is legally demanded. (See page 9, page 10.) 11