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Standardization of Internationalized Domain Name at IETF 24 Jan 2002 Yoshiro YONEYA JPNIC.

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Presentation on theme: "Standardization of Internationalized Domain Name at IETF 24 Jan 2002 Yoshiro YONEYA JPNIC."— Presentation transcript:

1 Standardization of Internationalized Domain Name at IETF 24 Jan 2002 Yoshiro YONEYA JPNIC

2 24 Jan 2002APAN2002 Conference2 What is IDN? Internationalized Domain Name. –Current domain name is represented with ASCII alpha-numeric and hyphen characters. –IDN is a technical challenge to represent domain name with not only ASCII but also NON-ASCII characters.

3 24 Jan 2002APAN2002 Conference3 What is Internationalization? Framework to extend character repertoire for domain names. Need to be a Global Standard not to lose global communication. IETF IDN (Internationalized Domain Name) WG is doing the work. Some confusion by using the word ‘Multilingualization’. –Character is just one of a component of languages. –Multilingual domain name is a service level’s aspect.

4 24 Jan 2002APAN2002 Conference4 Internationalized Domain Names 华人. 公司.cn 華人. 商業.tw 高島屋. 会社.jp 삼성. 회사.kr 三星. 회사.kr الاهرام. م viagénie.qc.ca ישראל. קום ทีเอชนิค. พาณิชย์. ไทย 現代.com ヤフー.com http://www.jdna.jp/activities/event/jdn-tutorial/IDNSDK.pdf

5 24 Jan 2002APAN2002 Conference5 Why IDN? Increases of the Internet users who are not familiar with English. –Easy to memorize, type in, etc. Drastic changes of usage of domain name. –Domain name is now used as not only host name but also signboard. Creates new business opportunities. –Many ventures began services.

6 24 Jan 2002APAN2002 Conference6 Drawback of IDN Loses global acceptability at end-user interface. –Hard to type in or display NON-ASCII characters without appropriate I/O devices and / or softwares. Cause impact to the operation. –Requires software update and / or additional processing. –Deployment issue.

7 24 Jan 2002APAN2002 Conference7 History of IDN WG Established on Jan 2000. –Mainly discussion is done on mailing list. Had 1st meeting at 47th IETF at Adelaide. –From then, having meeting every IETF. Decided WG’s solution at last (52nd) IETF. –IDNA, NAMEPREP and Punycode (formerly known as AMC-ACE-Z). –Waiting for WG last call.

8 24 Jan 2002APAN2002 Conference8 Scope and priority of IDN WG Provide standard. –Not to divide the global connectivity and communication of the Internet. Backward compatibility. –Compatibility with current DNS and application protocols to work with current Internet infrastructure. No localization. –Independent from certain regions, countries and / or languages –Refer to existing universal standards –Common framework essential to internationalization

9 24 Jan 2002APAN2002 Conference9 IDNA (Internationalizing Domain Names In Applications) draft-ietf-idn-idna-06.txt An architecture denotes how to process IDN. –Use Unicode which is upper compatible with ASCII as a character codeset. –Normalize internal representation of characters which has multiple code points such as upper/lower, full- width/half-width and composing characters, into a single representation not to fail matching. –Represent NON-ASCII characters which inputted or displayed at user interface as an ASCII Compatible Encoding (ACE) string on the Network. –Those processes be performed in application software.

10 24 Jan 2002APAN2002 Conference10 Important point of IDNA Representation at the user interface layer and the network layer is different. –Though the same for ASCII domain names. Application solution. –Least impact to the Internet infrastructure.

11 24 Jan 2002APAN2002 Conference11 Image of the IDNA User Internal Representation UI API Application servers End system Application Local Int’l Resolver DNS servers NAMEPREP To/From Unicode To/From ACE NAMEPREP To/From ACE To/From Unicode

12 24 Jan 2002APAN2002 Conference12 NAMEPREP (Stringprep Profile for Internationalized Host Names) draft-ietf-idn-nameprep-07.txt Profile for STRINGPREP (Preparation of Internationalized Strings) –draft-hoffman-stringprep-00.txt Some scripts such as alphabet have multiple representation for a character. –Domain name is case insensitive. Normalization process to unify representation of strings that is the same in meaning or displaying into a single representation. –Case (upper / lower) –Compatible character (full / half width) –Composing character

13 24 Jan 2002APAN2002 Conference13 Important point of NAMEPREP Normalize representation of Internationalized domain name string to match correctly. –‘a’ vs ‘A’ –‘u’+‘¨’ vs ‘ü’ –‘ ア ’ vs ‘ ア ’

14 24 Jan 2002APAN2002 Conference14 Processes in NAMEPREP 1.map Case folding of upper/lower characters (UTR#21) 2.normalize Normalize representation of string (UAX#15 NFKC) 3.prohibit Check out inappropriate character as domain name.

15 24 Jan 2002APAN2002 Conference15 ACE (ASCII Compatible Encoding) Represent NON-ASCII characters by ASCII characters. –Easy to apply current DNS. –Least impact to current applications. Decreases maximum characters in each label. –Penalty of using only 5bit to represent 8bit data. –Requires some sort of compression algorithm.

16 24 Jan 2002APAN2002 Conference16 ACE Identifier Requires explicit ACE-identifier. –For reverse conversion. –Choice of ACE-ID is political issue. ACE-ID itself is ASCII string, so that if any proposal for ACE-ID is raised, it will be registered as ASCII domain name. Actually happened at gTLD. IANA will assign the ACE-ID.

17 24 Jan 2002APAN2002 Conference17 Criteria of ACE selection Simple algorithm. –For ease implementation. –Interoperability. Effective compression results for practical IDNs. –To accommodate characters as much as possible. bilateral corresponding between encoding and decoding. –To avoid existence of alternative encoded representation for one IDN. –Security consideration.

18 24 Jan 2002APAN2002 Conference18 Comparison of ACE proposals RACEBQ-- 3BS6KZZMRKPDBSJQ4EYKIMHTKQGYUZU 2CM.JP Punycod e ZQ-- ECKWD4C7C777U7MWO4BOV4JIOAU09J. JP Encoding sample of ‘ 日本語ドメイン名試験.JP’ Evaluation result from existing Japanese JP domain names

19 24 Jan 2002APAN2002 Conference19 Punycode draft-ietf-idn-punycode-00.txt Selected ACE of IDN WG. Compression algorithm. –Extract characters by ascending order of codepoint. –Encode difference of codepoint from previously processed character’s and the position into an integer. –Extract Letters, Digits and Hyphen as bootstring. ASCII conversion algorithm. –Introduced new concept named ‘Generalized variable- length integers’. –BASE36 (A-Z, 0-9).

20 24 Jan 2002APAN2002 Conference20 Compression process of Punycode (simplified for understanding) “ 文字列例 ” Compression. 1.1:U+6587 2:U+5B57 3:U+5217 4:U+4F8B 2.4:0x4F8B 3:0x28C 2:0x440 1:0xA30 3.0x13E30 0xA33 0x1102 0x28C1 sort, diff To integer (diff*chars+ position)

21 24 Jan 2002APAN2002 Conference21 Generalized variable-length integers of Punycode 12345 in decimal is represented as 1*10^4+2*10^3+3*10^2+4*10^1+5*10^0 Digits in all place are 0-9, so components in sequential 12345 cannot distinguish 123 and 45 or 1234 and 5. Furthermore, 012345 and 12345 are the same value with different representation. GVLI (Generalized variable-length integers) is an idea to solve this problem. Defines threshold for each place, and recognize a number below the threshold is delimiter. Threshold is an appropriate number smaller than base number.

22 24 Jan 2002APAN2002 Conference22 Encoding process of Punycode (simplified for understanding) Assign A-Z0-9 to GVLI. –Assume 36 for base, 10, 18, 25, 25 for thresholds. 1.0x13E30 0xA33 0x1102 0x28C1 2. OIUD 3. BS4 4. CN8 5. XML “ 文字列例 ”=>“OUIDBS4CN8XML”. –Real Punycode generates “FSQW5D78MBSK”. 24*1+18*26 (=1*(36-10)) +30*468 (=26*(36-18)) +13*5148 (=468*(36-25)) 11*1+28*26+4*468 12*1+23*26+8*468 33*1+22*26+21*468

23 24 Jan 2002APAN2002 Conference23 Standardization of IDN is just the start point of utilization End users uses IDN with application softwares. –Web, Mail, etc. IDNA requires application’s correspondence. Must define how to deal IDNs in application protocols. Standardization of IDN does not mean ready to use. Just a start point for applications incorporating new features.

24 24 Jan 2002APAN2002 Conference24 HTTP Request (DNS resolve only) Web User http:// ジェーピーニック.JP/ ZQ--HCKQZ9BZB1CYRB.JP Web server ’ s IP adress GET http:// ジェーピーニック.JP/ HTTP/1.1 Host: ジェーピーニック.JP Referer: http:// ジェーピーニック.JP/ Error! DNS

25 24 Jan 2002APAN2002 Conference25 HTTP Request (ACE in HTTP header) Web User http:// ジェーピーニック.JP/ ZQ--HCKQZ9BZB1CYRB.JP Web server ’ s IP address GET http://ZQ--HCKQZ9BZB1CYRB.JP/ HTTP/1.1 Host: ZQ--HCKQZ9BZB1CYRB.JP Referer: http://ZQ--HCKQZ9BZB1CYRB.JP/ Contents DNS

26 24 Jan 2002APAN2002 Conference26 References IETF IDN WG Web page –http://www.i-d-n.net/ Unicode Consortium –http://www.unicode.org/

27 24 Jan 2002APAN2002 Conference27 Acknowledgement Telecommunications Advancement Organization of Japan (TAO). –JPNIC’s research activity of security investigation of IDN is a part of TAO’s research. –http://www.shiba.tao.go.jp/

28 24 Jan 2002APAN2002 Conference28 IDN Compliant clients & implementations Mozilla http://playground.i-dns.net/mozilla/index.html –Plug-in to Mozilla, resolution using RACE Opera http://www.opera.com/ –Native, Resolution using RACE Internet Explorer 5 or higher http://www.microsoft.com/windows/ie/default.asp –Uses keyword search engine as RACE converter mDNkit http://www.nic.ad.jp/jp/research/idn/mdnkit/download/ –Opensource toolkit for developing IDN compliant softwares


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