Network Working Group                                             K. Ono
Request for Comments: 4189                                  S. Tachimoto
Category: Informational                                  NTT Corporation
                                                            October 2005
              Requirements for End-to-Middle Security for
                 the Session Initiation Protocol (SIP)

Status of This Memo


This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.


Copyright Notice


Copyright (C) The Internet Society (2005).




A Session Initiation Protocol (SIP) User Agent (UA) does not always trust all intermediaries in its request path to inspect its message bodies and/or headers contained in its message. The UA might want to protect the message bodies and/or headers from intermediaries, except those that provide services based on its content. This situation requires a mechanism called "end-to-middle security" to secure the information passed between the UA and intermediaries, which does not interfere with end-to-end security. This document defines a set of requirements for a mechanism to achieve end-to-middle security.

セッション開始プロトコル(SIP)ユーザエージェント(UA)は、常にそのメッセージ本体および/またはそのメッセージに含まれるヘッダを検査するために、その要求のパス内のすべての仲介を信頼していません。 UAは、その内容に基づいてサービスを提供するものを除き、仲介者からのメッセージ本文および/またはヘッダを保護することをお勧めします。この状況は、エンドツーエンドのセキュリティを妨げないUAと仲介者の間で渡される情報を、確保するために、「エンド・ツー・ミドルセキュリティ」と呼ばれる仕組みが必要です。この文書では、エンド・ツー・ミドルセキュリティを達成するためのメカニズムのための要件のセットを定義します。

Table of Contents


   1. Introduction ....................................................2
      1.1. Conventions Used in This Document ..........................2
   2. Use Cases .......................................................2
      2.1. Examples of Scenarios ......................................2
      2.2. Service Examples ...........................................4
   3. Scope of End-to-Middle Security .................................6
   4. Requirements for a Solution .....................................6
      4.1. General Requirements .......................................6
      4.2. Requirements for End-to-Middle Confidentiality .............7
      4.3. Requirements for End-to-Middle Integrity ...................7
   5. Security Considerations .........................................8
   6. Acknowledgments .................................................9
   7. References ......................................................9
      7.1. Normative References .......................................9
      7.2. Informative References .....................................9
1. Introduction
1. はじめに

The Session Initiation Protocol (SIP) [2] supports hop-by-hop security using Transport Layer Security (TLS) [3] and end-to-end security using Secure MIME (S/MIME) [4]. Use of TLS assumes that a SIP UA trusts all proxy servers along its request path to inspect the message bodies contained in the message, and use of S/MIME assumes that a SIP UA does not trust any proxy servers to do so.

[3]、エンドツーエンドのセキュリティセキュアMIME(S / MIME)を使用して、セッション開始プロトコル(SIP)[2]トランスポート層セキュリティ(TLS)を使用して、ホップバイホップセキュリティをサポートしている[4]。 TLSを使用すると、その要求のパスに沿ったすべてのプロキシサーバがメッセージに含まれるメッセージ本文を検査するSIP UA信託と仮定して、S / MIMEを使用すると、SIP UAがそうするために、任意のプロキシサーバーを信頼していないことを前提としています。

However, there is a model in which trusted and partially-trusted proxy servers are mixed along a message path. The partially-trusted proxy servers are only trusted to provide SIP routing, but these proxy servers are not trusted by users to inspect its data, except the routing headers. A hop-by-hop confidentiality service using TLS is not suitable for this model. An end-to-end confidentiality service using S/MIME is also not suitable when the intermediaries provide services based on reading the message bodies and/or headers. This problem is described in Section 23 of [2].

しかし、信頼できると部分的に信頼されたプロキシサーバがメッセージの経路に沿って混合されたモデルがあります。部分的に信頼されたプロキシサーバーのみSIPルーティングを提供するために信頼されているが、これらのプロキシサーバーは、ルーティングヘッダを除いて、そのデータを検査するために、ユーザーから信頼されていません。 TLSを使用したホップバイホップ機密性サービスは、このモデルには適していません。仲介は、メッセージ本文および/またはヘッダを読みに基づいてサービスを提供する際にS / MIMEを使用して、エンドツーエンドの機密性サービスも適していません。この問題は、[2]のセクション23に記載されています。

In some cases, a UA might want to protect its message bodies and/or headers from proxy servers along its request path, except from those that provide services based on reading its message bodies and/or headers. Conversely, a proxy server might want to view the message bodies and/or headers to sufficiently provide these services. Such proxy servers are not always the first hop from the UA. This situation requires a security mechanism to secure message bodies and/or headers between the UA and the proxy servers, while disclosing information to those that need it. We call this "end-to-middle security".


1.1. Conventions Used in This Document
1.1. このドキュメントの表記規則

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [1].

この文書のキーワード "MUST"、 "MUST NOT"、 "REQUIRED"、、、、 "べきではない" "べきである" "ないもの" "ものとし"、 "推奨"、 "MAY"、および "OPTIONAL" はありますRFC-2119に記載されるように解釈される[1]。

2. Use Cases
2.1. Examples of Scenarios
2.1. シナリオの例

We describe here examples of scenarios in which trusted and partially-trusted proxy servers both exist in a message path. These situations demonstrate the reasons why end-to-middle security is required.


In the following example, User #1 does not know the security policies or services provided by Proxy server #1 (Proxy#1). User #1 sends a MESSAGE [5] request including S/MIME-encrypted message content for end-to-end security, as shown in Figure 1, while Proxy #1 rejects the request based on its strict security policy that prohibits the forwarding of unknown data.

次の例では、ユーザ#1は、プロキシサーバ#1(プロキシ#1)によって提供されるセキュリティポリシーやサービスを知っていません。プロキシ#1の転送を禁止し、その厳密なセキュリティポリシーに基づいて、要求を拒否しながら、図1に示すように、ユーザ#1は、エンドツーエンドのセキュリティのためのS / MIME暗号化メッセージの内容を含むメッセージ[5]要求を送信します未知のデータ。

               Home network
               | +-----+     +-----+ |   +-----+     +-----+
   User #1-----| |  C  |-----| [C] |-----| [C] |-----|  C  |-----User #2
               | +-----+     +-----+ |   +-----+     +-----+
               | UA #1      Proxy #1 |   Proxy #2     UA #2

C: Content that UA #1 allows the entity to inspect [C]: Content that UA #1 prevents the entity from inspecting


Figure 1: Deployment example #1


In the second example, Proxy server #1 is the home proxy server of User #1 using UA #1. User #1 communicates with User #2 through Proxy #1 and Proxy #2, as shown in Figure 2. Although User #1 already knows Proxy #1's security policy, which requires the inspection of the content of the MESSAGE request, User #1 does not know whether Proxy #2 is trustworthy, and thus wants to protect the message bodies in the request. To accomplish this, UA #1 will need to be able to grant a trusted intermediary (Proxy #1) to inspect message bodies, while preserving their confidentiality from other intermediaries (Proxy #2).


Even if UA #1's request message authorizes Proxy #1 to inspect the message bodies, UA #1 is unable to authorize the same proxy server to inspect the message bodies in subsequent MESSAGE requests from UA #2.


              Home network
              | +-----+     +-----+ |   +-----+     +-----+
  User #1-----| |  C  |-----|  C  |-----| [C] |-----|  C  |----- User #2
              | +-----+     +-----+ |   +-----+     +-----+
              | UA #1      Proxy #1 |   Proxy #2     UA #2

C: Content that UA #1 needs to disclose [C]: Content that UA #1 needs to protect


Figure 2: Deployment example #2


In the third example, User #1 connects UA #1 to a proxy server in a visited (potentially insecure) network, e.g., a hotspot service or a roaming service. Since User #1 wants to utilize certain home network services, UA #1 connects to a home proxy server, Proxy #1. However, UA #1 must connect to Proxy #1 via the proxy server of the visited network (Proxy A), because User #1 must follow the policy of that network. Proxy A performs access control based on the destination addresses of calls. User #1 only trusts Proxy A to route requests, not to inspect the message bodies the requests contain, as shown in Figure 3. User #1 trusts Proxy #1 both to route the requests and to inspect the message bodies.


The same problems as in the second example also exist here.


               Visited network
              | +-----+     +-----+ |   +-----+     +-----+     +-----+
   User #1 -- | |  C  |-----| [C] |-----|  C  |-----| [C] |-----|  C  |
              | +-----+     +-----+ |   +-----+     +-----+     +-----+
              | UA #1       Proxy A |   Proxy #1     Proxy #2    UA #2

C: Content that UA #1 needs to disclose [C]: Content that UA #1 needs to protect


Figure 3: Deployment example #3


2.2. Service Examples
2.2. サービスの例

We describe here several services that require end-to-middle security.


2.2.1. Logging Services for Instant Messages
2.2.1. インスタントメッセージのロギングサービス

Logging Services are provided by the archiving function, which is located in the proxy server, that logs the message content exchanged between UAs. The archiving function could be located at the originator network and/or the destination network. When the content of an instant message contains private information, UACs (UA Clients) encrypt the content for the UASes (UA Servers). The archiving function needs to log the content in a message body in bidirectional MESSAGE requests in such a way that the data is decipherable. The archiving function also needs a way to verify the data integrity of the content before logging.


This service might be deployed in financial networks, health care service provider's networks, as well as other networks in which archiving communication is required by their security policies.


2.2.2. Non-emergency Call Routing Based on the Location Object
2.2.2. Locationオブジェクトに基づく非緊急コールルーティング

The Location Object [6] includes a person's geographical location information that is privacy-sensitive. Some proxy servers will have the ability to provide routing based on the geographical location information. When UAs want to employ location-based routing in non-emergency situations, the UAs need to connect to the proxy servers with such a capability and disclose the geographical location information contained in the message body of the INVITE request, while protecting it from other proxy servers along the request path. The Location Object also needs to be verified for data integrity by the proxy servers before location-based routing is applied. Sometimes the UACs want to send the Location Object to the UASes. This is another good example that presents the need for UACs to simultaneously send secure data to a proxy server and to the UASes.

Locationオブジェクトは、[6]プライバシーに敏感な人の地理的位置情報を含んでいます。プロキシサーバーは、地理的位置情報に基づいてルーティングを提供する能力を持つことになります。 UAが非緊急事態におけるロケーションベースのルーティングを採用したい場合は、他のプロキシからそれを保護しながら、UAは、このような機能をプロキシサーバに接続し、INVITE要求のメッセージボディに含まれている地理的位置情報を開示する必要があります要求パスに沿っサーバ。 Locationオブジェクトは、ロケーションベースのルーティングが適用される前に、プロキシサーバによるデータの整合性を検証する必要があります。時には求めるUACはUASesにLocationオブジェクトを送りたいです。これが求めるUACが同時にプロキシサーバへとUASesへの安全なデータを送信するための必要性を提示し、別の良い例です。

2.2.3. User Authentication
2.2.3. ユーザ認証 User Authentication Using the AIBs。 AIBsを使用したユーザー認証

The Authenticated Identity Bodies (AIBs) [7] is a digitally-signed data that is used for identifying users. Proxy servers that need to authenticate a user, verify the signature. When the originator needs anonymity, the user identity in the AIB is encrypted before being signed. Proxy servers that authenticate the user need to decrypt the body in order to view the user identity in the AIB. Such proxy servers can be located adjacently and/or non-adjacently to the UA.


The AIB could be included in all request/response messages. The proxy server needs to view it in request messages in order to authenticate users. Another proxy server sometimes needs to view it in response messages for user authentication.

AIBは、すべての要求/応答メッセージに含めることができます。プロキシサーバーは、ユーザーを認証するために要求メッセージで表示する必要があります。別のプロキシサーバは、時々、ユーザ認証用の応答メッセージで表示する必要があります。 User Authentication in HTTP Digest Authentication。 HTTPダイジェスト認証でユーザー認証

User authentication data for HTTP Digest authentication [8] includes potentially private information, such as a user name. The user authentication data can be set only in a SIP header of request messages. This information needs to be transmitted securely to servers that authenticate users, located either adjacently and/or non-adjacently to the UA.


2.2.4. Media-related Services
2.2.4. メディア関連サービス

Firewall traversal is an example of services based on media information in a message body, such as the Session Description Protocol (SDP) [9]. A firewall entity that supports the SIP protocol, or a midcom [10] agent co-located with a proxy server,

ファイヤウォールトラバーサルは、セッション記述プロトコル(SDP)などのメッセージ本体内のメディア情報に基づいて、サービスの例である[9]。 SIPプロトコル、またはMIDCOMをサポートするファイアウォールエンティティ[10]エージェント、プロキシサーバと同じ場所に配置

controls a firewall based on the address and port information of media streams in the SDP offer/answer. The address and port information in the SDP needs to be transmitted securely to recipient UAs and the proxy server operating as a midcom agent. Therefore, there is a need for a proxy server to be able to decrypt the SDP, as well as to verify the integrity of the SDP.

SDPオファー/アンサー内のメディア・ストリームのアドレスとポート情報に基づいてファイアウォールを制御します。 SDP内のアドレスとポート情報は、受信者UAとMIDCOMエージェントとして動作するプロキシサーバに安全に送信される必要があります。そのため、プロキシサーバは、SDPを復号化するだけでなく、SDPの整合性を検証することができるようにするための必要性があります。

When the SDP includes key parameters for Secure RTP (SRTP) [11], the key parameters need to be encrypted only for end-to-end confidentiality.


3. Scope of End-to-Middle Security

End-to-middle security consists of user authentication, data integrity, and data confidentiality. Providing data integrity requires authenticating peer who creates the data. However, this document only describes requirements for data confidentiality and data integrity, since end-to-middle authentication is covered by existing mechanisms such as HTTP Digest authentication, S/MIME Cryptographic Message Syntax (CMS) SignedData body [12], or an AIB.

エンド・ツー・ミドルセキュリティは、ユーザー認証、データの整合性、およびデータの機密性から構成されています。データの整合性を提供することで、データを作成し、ピアの認証が必要です。エンド・ツー・ミドル認証は、このようなHTTPダイジェスト認証、S / MIME暗号メッセージ構文(CMS)のSignedData体[12]、またはAIBなどの既存のメカニズムによって覆われているので、この文書のみ、データの機密性とデータ整合性のための要件を記述する。

As for data integrity, the CMS SignedData body can be used for verification of the data integrity and authentication of the signer by any entities. The CMS SignedData body can be used for end-to-middle security and end-to-end security simultaneously. However, a proxy server generally does not verify the data integrity using the CMS SignedData body, and there is no way for a UA to request the proxy server to verify the message. Therefore, some new mechanisms are needed to achieve data integrity for end-to-middle security.

データの整合性については、CMSのSignedDataボディは、任意のエンティティによって署名者のデータ整合性と認証の検証のために使用することができます。 CMSのSignedData体は同時に、エンド・ツー・ミドルセキュリティとエンドツーエンドのセキュリティのために使用することができます。しかし、プロキシサーバは、一般的にCMSのSignedDataボディを使用して、データの整合性を検証しないと、UAがメッセージを確認するためにプロキシサーバーを要求するための方法はありません。そのため、いくつかの新しいメカニズムは、エンド・ツー・ミドルセキュリティのためのデータの整合性を達成するために必要とされています。

This document mainly discusses requirements for data confidentiality and the integrity of end-to-middle security.


4. Requirements for a Solution

We describe here requirements for a solution. The requirements are mainly applied during the phase of a dialog creation or sending a MESSAGE request.


4.1. General Requirements
4.1. 一般要件

The following are general requirements for end-to-middle confidentiality and integrity.


REQ-GEN-1: The solution SHOULD have little impact on the way a UA handles S/MIME-secured messages.

REQ-GEN-1:ソリューションは、UAは、S / MIMEで保護されたメッセージを処理する方法にはほとんど影響を持っているべきです。

REQ-GEN-2: It SHOULD NOT have an impact on proxy servers that do not provide services based on S/MIME-secured bodies in terms of handling the existing SIP headers.

REQ-GEN-2:これは、既存のSIPヘッダを処理するという点でS / MIMEで保護されたボディに基づいてサービスを提供していないプロキシサーバに影響を持つべきではありません。

REQ-GEN-3: It SHOULD NOT violate the standardized mechanism of proxy servers in terms of handling message bodies.


REQ-GEN-4: It SHOULD allow a UA to discover security policies of proxy servers. Security policies imply what data is needed to disclose and/or verify in a message.


                 This requirement is necessary when the UA does not know
                 statically which proxy servers or domains need
                 disclosing data and/or verification.
4.2. Requirements for End-to-Middle Confidentiality
4.2. エンド・ツー・ミドル・機密性の要件

REQ-CONF-1: The solution MUST allow encrypted data to be shared with the recipient UA and a proxy server, when a UA wants.


REQ-CONF-2: It MUST NOT violate end-to-end encryption when the encrypted data does not need to be shared with any proxy servers.


REQ-CONF-3: It SHOULD allow a UA to request a proxy server to view specific message bodies. The request itself SHOULD be secure; namely it SHOULD be authenticated for the UA and verified for the data integrity.


REQ-CONF-4: It MAY allow a UA to request that the recipient UA disclose information to the proxy server to which the requesting UA is initially disclosing information. The request itself SHOULD be secure; namely it SHOULD be authenticated for the UA and verified for the data integrity.


                  This requirement is necessary when a provider
                  operating the proxy server allows its security
                  policies to be revealed to the provider serving the
                  recipient UA.
4.3. Requirements for End-to-Middle Integrity
4.3. エンド・ツー・ミドル・整合性の要件

This section enumerates the requirements for the end-to-middle integrity. Verifying the data integrity requires checking that the data is created by the authenticated user and not forged by a malicious user. Therefore, verification of the data integrity requires the user authentication.


REQ-INT-1: The solution SHOULD work even when the SIP end-to-end authentication and integrity services are enabled.


REQ-INT-2: It SHOULD allow a UA to request a proxy server to verify specific message bodies and authenticate the user. The request itself SHOULD be secure; namely it SHOULD be authenticated for the UA and verified for the data integrity.


REQ-INT-3: It SHOULD allow a UA to request the recipient UA to send the verification data of the same information that the requesting UA is providing to the proxy server. The request itself SHOULD be secure; namely it SHOULD be authenticated for the UA and verified for the data integrity.


                 This requirement is necessary when a provider operating
                 the proxy server allows its security policies to be
                 revealed to the provider serving the recipient UA.
5. Security Considerations

This document describes the requirements for confidentiality and integrity between a UA and a proxy server. Although this document does not cover any requirements for authentication, verifying the data integrity requires peer authentication. Also, peer authentication is important in order to prevent attacks from malicious users and servers.


The end-to-middle security requires additional processing on message bodies, such as unpacking MIME structure, data decryption, and/or signature verification to proxy servers. Therefore, the proxy servers that enable end-to-middle security are vulnerable to a Denial-of-Services attack. A threat model is where a malicious user sends many complicated-MIME-structure messages to a proxy server, containing user authentication data obtained by eavesdropping. Another threat model is where a malicious proxy server sends many complicated-MIME-structure messages to a proxy server, containing the source IP address and the Via header of an adjacent proxy server. These attacks will slow down the overall performance of target proxy servers.


To prevent these attacks, user and server authentication mechanisms need to be protected against replay attacks, or the user and server authentication always need to be executed simultaneously with protection of data integrity. In order to prevent these attacks, the following requirements should be met.


o The solution MUST support mutual authentication, data confidentiality, and data integrity protection between a UA and a proxy server.


o It SHOULD support protection against a replay attack for user authentication.


o It SHOULD simultaneously support user authentication and data integrity protection.


         These last two requirements are met by HTTP Digest

o It MUST support mutual authentication, data confidentiality, and data integrity protection between proxy servers.


o It SHOULD support protection against a replay attack for server authentication.


o It SHOULD simultaneously support server authentication and data integrity protection.


These last three requirements are met by TLS.


6. Acknowledgments

The authors would like to thank to Rohan Mahy and Cullen Jennings for their initial support of this concept, and to Jon Peterson, Gonzalo Camarillo, Sean Olson, Mark Baugher, Mary Barnes, and others for their reviews and constructive comments.


7. References
7.1. Normative References
7.1. 引用規格

[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[1]ブラドナーのは、S.は、BCP 14、RFC 2119、1997年3月の "RFCsにおける使用のためのレベルを示すために"。

[2] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002.

[2]ローゼンバーグ、J.、Schulzrinneと、H.、カマリロ、G.、ジョンストン、A.、ピーターソン、J.、スパークス、R.、ハンドレー、M.、およびE.学生、 "SIP:セッション開始プロトコル" 、RFC 3261、2002年6月。

7.2. Informative References
7.2. 参考文献

[3] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999.

[3]ダークス、T.とC.アレン、 "TLSプロトコルバージョン1.0"、RFC 2246、1999年1月。

[4] Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Certificate Handling", RFC 3850, July 2004.

[4] Ramsdell、B.は、RFC 3850、2004年7月 "/多目的インターネットメール拡張(S / MIME)バージョン3.1証明書の処理を固定します"。

[5] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., and D. Gurle, "Session Initiation Protocol (SIP) Extension for Instant Messaging", RFC 3428, December 2002.

[5]キャンベル、B.、ローゼンバーグ、J.、Schulzrinneと、H.、のHuitema、C.、およびD. Gurle、 "インスタントメッセージングのためのセッション開始プロトコル(SIP)拡張子"、RFC 3428、2002年12月。

[6] Peterson, J., "A Presence-based GEOPRIV Location Object Format", RFC 4119, October 2005.

[6]ピーターソン、J.、 "プレゼンスベースGEOPRIVロケーション・オブジェクト・フォーマット"、RFC 4119、2005年10月。

[7] Peterson, J., "Session Initiation Protocol (SIP) Authenticated Identity Body (AIB) Format", RFC 3893, September 2004.

[7]ピーターソン、J.、 "セッション開始プロトコル(SIP)認証済みアイデンティティボディ(AIB)フォーマット"、RFC 3893、2004年9月。

[8] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A., and L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999.

[8]フランクス、J.、ハラム・ベイカー、P.、Hostetler、J.、ローレンス、S.、リーチ、P.、Luotonen、A.、およびL.スチュワート、 "HTTP認証:基本とダイジェストアクセス認証" 、RFC 2617、1999年6月。

[9] Handley, M. and V. Jacobson, "SDP: Session Description Protocol", RFC 2327, April 1998.

[9]ハンドレー、M.およびV. Jacobsonの "SDP:セッション記述プロトコル"、RFC 2327、1998年4月。

[10] Srisuresh, P., Kuthan, J., Rosenberg, J., Molitor, A., and A. Rayhan, "Middlebox communication architecture and framework", RFC 3303, August 2002.

[10] Srisuresh、P.、Kuthan、J.、ローゼンバーグ、J.、モリター、A.、およびA. Rayhan、 "ミドル通信アーキテクチャおよびフレームワーク"、RFC 3303、2002年8月。

[11] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004.

[11] Baugher、M.、マグリュー、D.、Naslund、M.、カララ、E.、およびK. Norrman、 "セキュアリアルタイム転送プロトコル(SRTP)"、RFC 3711、2004年3月。

[12] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3852, July 2004.

[12] Housley氏、R.、 "暗号メッセージ構文(CMS)"、RFC 3852、2004年7月。

Authors' Addresses


Kumiko Ono Network Service Systems Laboratories NTT Corporation 9-11, Midori-Cho 3-Chome Musashino-shi, Tokyo 180-8585 Japan

くみこ おの ねとぉrk せrゔぃせ Sysてms ぁぼらとりえs んっt こrぽらちおん 9ー11、 みどりーちょ 3ーちょめ むさしのーし、 ときょ 180ー8585 じゃぱん



Shinya Tachimoto Network Service Systems Laboratories NTT Corporation 9-11, Midori-Cho 3-Chome Musashino-shi, Tokyo 180-8585 Japan

しにゃ たちもと ねとぉrk せrゔぃせ Sysてms ぁぼらとりえs んっt こrぽらちおん 9ー11、 みどりーちょ 3ーちょめ むさしのーし、 ときょ 180ー8585 じゃぱん



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