Internet Engineering Task Force (IETF) A. Melnikov, Ed.
Request for Comments: 8398 Isode Ltd
Updates: 5280 W. Chuang, Ed.
Category: Standards Track Google, Inc.
ISSN: 2070-1721 May 2018
Internet Engineering Task Force (IETF) A. Melnikov, Ed.
Request for Comments: 8398 Isode Ltd
Updates: 5280 W. Chuang, Ed.
Category: Standards Track Google, Inc.
ISSN: 2070-1721 May 2018
Internationalized Email Addresses in X.509 Certificates
X.509证书中的国际化电子邮件地址
Abstract
摘要
This document defines a new name form for inclusion in the otherName field of an X.509 Subject Alternative Name and Issuer Alternative Name extension that allows a certificate subject to be associated with an internationalized email address.
本文档定义了一个新的名称表单，用于包含在X.509使用者替代名称和颁发者替代名称扩展的otherName字段中，该扩展允许证书使用者与国际化电子邮件地址相关联。
This document updates RFC 5280.
本文件更新了RFC 5280。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8398.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问https://www.rfc-editor.org/info/rfc8398.
Copyright Notice
版权公告
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2018 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(https://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. Name Definitions . . . . . . . . . . . . . . . . . . . . . . 3
4. IDNA2008 . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Matching of Internationalized Email Addresses in X.509
Certificates . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Name Constraints in Path Validation . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 10
Appendix B. Example of SmtpUTF8Mailbox . . . . . . . . . . . . . 11
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. Name Definitions . . . . . . . . . . . . . . . . . . . . . . 3
4. IDNA2008 . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Matching of Internationalized Email Addresses in X.509
Certificates . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Name Constraints in Path Validation . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 10
Appendix B. Example of SmtpUTF8Mailbox . . . . . . . . . . . . . 11
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
[RFC5280] defines the rfc822Name subjectAltName name type for representing email addresses as described in [RFC5321]. The syntax of rfc822Name is restricted to a subset of US-ASCII characters and thus can't be used to represent internationalized email addresses [RFC6531]. This document defines a new otherName variant to represent internationalized email addresses. In addition this document requires all email address domains in X.509 certificates to conform to IDNA2008 [RFC5890].
[RFC5280]定义rfc822Name subjectAltName名称类型，用于表示[RFC5321]中所述的电子邮件地址。rfc822Name的语法仅限于US-ASCII字符的子集，因此不能用于表示国际化电子邮件地址[RFC6531]。本文档定义了一个新的otherName变体来表示国际化的电子邮件地址。此外，本文档要求X.509证书中的所有电子邮件地址域符合IDNA2008[RFC5890]。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
The formal syntax uses the Augmented Backus-Naur Form (ABNF) [RFC5234] notation.
形式语法使用增广的Backus-Naur形式（ABNF）[RFC5234]表示法。
The GeneralName structure is defined in [RFC5280] and supports many different name forms including otherName for extensibility. This section specifies the SmtpUTF8Mailbox name form of otherName so that internationalized email addresses can appear in the subjectAltName of a certificate, the issuerAltName of a certificate, or anywhere else that GeneralName is used.
GeneralName结构在[RFC5280]中定义，并支持多种不同的名称形式，包括otherName以实现扩展性。本节指定otherName的smtputf8邮箱名称形式，以便国际化电子邮件地址可以显示在证书的subjectAltName、证书的issuerAltName或使用GeneralName的任何其他位置。
id-on-SmtpUTF8Mailbox OBJECT IDENTIFIER ::= { id-on 9 }
id-on-SmtpUTF8Mailbox OBJECT IDENTIFIER ::= { id-on 9 }
SmtpUTF8Mailbox ::= UTF8String (SIZE (1..MAX))
-- SmtpUTF8Mailbox conforms to Mailbox as specified
-- in Section 3.3 of RFC 6531.
SmtpUTF8Mailbox ::= UTF8String (SIZE (1..MAX))
-- SmtpUTF8Mailbox conforms to Mailbox as specified
-- in Section 3.3 of RFC 6531.
When the subjectAltName (or issuerAltName) extension contains an internationalized email address with a non-ASCII local-part, the address MUST be stored in the SmtpUTF8Mailbox name form of otherName. The format of SmtpUTF8Mailbox is defined as the ABNF rule SmtpUTF8Mailbox. SmtpUTF8Mailbox is a modified version of the internationalized Mailbox that was defined in Section 3.3 of [RFC6531], which was derived from Mailbox as defined in Section 4.1.2 of [RFC5321]. [RFC6531] defines the following ABNF rules for Mailbox whose parts are modified for internationalization: <Local-part>, <Dot-string>, <Quoted-string>, <QcontentSMTP>, <Domain>, and <Atom>. In particular, <Local-part> was updated to also support UTF8-non-ascii. UTF8-non-ascii was described by Section 3.1 of [RFC6532]. Also, domain was extended to support U-labels, as defined in [RFC5890].
当subjectAltName（或issuerAltName）扩展名包含具有非ASCII本地部分的国际化电子邮件地址时，该地址必须存储在otherName的smtputf8邮箱名称格式中。SmtpUTF8Mailbox的格式定义为ABNF规则SmtpUTF8Mailbox。SmtpUTF8Mailbox是[RFC6531]第3.3节中定义的国际化邮箱的修改版本，它源自[RFC5321]第4.1.2节中定义的邮箱。[RFC6531]为其部分被修改以实现国际化的邮箱定义以下ABNF规则：<Local part>、<Dot string>、<Quoted string>、<QcontentSMTP>、<Domain>和<Atom>。特别是，<Local part>已更新为也支持UTF8非ascii。[RFC6532]第3.1节描述了UTF8非ascii码。此外，根据[RFC5890]中的定义，域被扩展以支持U型标签。
This document further refines internationalized Mailbox ABNF rules as described in [RFC6531] and calls this SmtpUTF8Mailbox. In SmtpUTF8Mailbox, labels that include non-ASCII characters MUST be stored in U-label (rather than A-label) form [RFC5890]. This restriction removes the need to determine which label encoding, A- or U-label, is present in the domain. As per Section 2.3.2.1 of [RFC5890], U-labels are encoded as UTF-8 [RFC3629] in Normalization Form C and other properties specified there. In SmtpUTF8Mailbox, domain labels that solely use ASCII characters (meaning neither A-nor U-labels) SHALL use NR-LDH restrictions as specified by Section 2.3.1 of [RFC5890] and SHALL be restricted to lowercase letters. NR-LDH stands for "Non-Reserved Letters Digits Hyphen" and is the set of LDH labels that do not have "--" characters in the third and forth character position, which excludes "tagged domain names" such as A-labels. Consistent with the treatment of rfc822Name in [RFC5280], SmtpUTF8Mailbox is an envelope <Mailbox> and has no
本文档进一步细化了[RFC6531]中所述的国际化邮箱ABNF规则，并将其称为SMTPUTF8邮箱。在SMTPUTF8邮箱中，包含非ASCII字符的标签必须以U-label（而不是A-label）形式存储[RFC5890]。此限制消除了确定域中存在哪个标签编码（A-或U-标签）的需要。根据[RFC5890]第2.3.2.1节，U型标签编码为标准化形式C中的UTF-8[RFC3629]和其中规定的其他属性。在SMTPUTF8邮箱中，仅使用ASCII字符的域标签（既不表示A标签也不表示U标签）应使用[RFC5890]第2.3.1节规定的NR-LDH限制，并应限制为小写字母。NR-LDH代表“非保留字母数字连字符”，是第三个和第四个字符位置没有“-”字符的LDH标签集，不包括“标记域名”，如A标签。与[RFC5280]中对rfc822Name的处理一致，SmtpUTF8Mailbox是一个信封<Mailbox>，没有
phrase (such as a common name) before it, has no comment (text surrounded in parentheses) after it, and is not surrounded by "<" and ">" characters.
短语（如通用名称）前面没有注释（括号中的文本），后面没有“<”和“>”字符。
Due to name constraint compatibility reasons described in Section 6, SmtpUTF8Mailbox subjectAltName MUST NOT be used unless the local-part of the email address contains non-ASCII characters. When the local-part is ASCII, rfc822Name subjectAltName MUST be used instead of SmtpUTF8Mailbox. This is compatible with legacy software that supports only rfc822Name (and not SmtpUTF8Mailbox). The appropriate usage of rfc822Name and SmtpUTF8Mailbox is summarized in Table 1 below.
由于第6节中描述的名称约束兼容性原因，除非电子邮件地址的本地部分包含非ASCII字符，否则不得使用SmtpUTF8Mailbox subjectAltName。当本地部分为ASCII时，必须使用rfc822Name subjectAltName而不是SmtpUTF8Mailbox。这与仅支持rfc822Name（而不支持SmtpUTF8Mailbox）的旧版软件兼容。下表1总结了rfc822Name和SmtpUTF8Mailbox的适当用法。
SmtpUTF8Mailbox is encoded as UTF8String. The UTF8String encoding MUST NOT contain a Byte-Order-Mark (BOM) [RFC3629] to aid consistency across implementations, particularly for comparison.
SMTPUTF8邮箱编码为UTF8String。UTF8String编码不得包含字节顺序标记（BOM）[RFC3629]以帮助实现一致性，尤其是用于比较。
+-----------------+-------------+--------------+-----------------+
| local-part char | domain char | domain label | subjectAltName |
+-----------------+-------------+--------------+-----------------+
| ASCII-only | ASCII-only | NR-LDH label | rfc822Name |
| non-ASCII | ASCII-only | NR-LDH label | SmtpUTF8Mailbox |
| ASCII-only | non-ASCII | A-label | rfc822Name |
| non-ASCII | non-ASCII | U-label | SmtpUTF8Mailbox |
+-----------------+-------------+--------------+-----------------+
+-----------------+-------------+--------------+-----------------+
| local-part char | domain char | domain label | subjectAltName |
+-----------------+-------------+--------------+-----------------+
| ASCII-only | ASCII-only | NR-LDH label | rfc822Name |
| non-ASCII | ASCII-only | NR-LDH label | SmtpUTF8Mailbox |
| ASCII-only | non-ASCII | A-label | rfc822Name |
| non-ASCII | non-ASCII | U-label | SmtpUTF8Mailbox |
+-----------------+-------------+--------------+-----------------+
Non-ASCII may additionally include ASCII characters.
非ASCII还可以包括ASCII字符。
Table 1: Email Address Formatting
表1：电子邮件地址格式
To facilitate comparison between email addresses, all email address domains in X.509 certificates MUST conform to IDNA2008 [RFC5890] (and avoid any "mappings" mentioned in that document). Use of non-conforming email address domains introduces the possibility of conversion errors between alternate forms. This applies to SmtpUTF8Mailbox and rfc822Name in subjectAltName, issuerAltName, and anywhere else that these are used.
为了便于电子邮件地址之间的比较，X.509证书中的所有电子邮件地址域必须符合IDNA2008[RFC5890]（并避免该文档中提到的任何“映射”）。使用不一致的电子邮件地址域可能会导致其他表单之间的转换错误。这适用于subjectAltName、issuerAltName中的SmtpUTF8Mailbox和rfc822Name，以及使用它们的任何其他位置。
In equivalence comparison with SmtpUTF8Mailbox, there may be some setup work on one or both inputs depending on whether the input is already in comparison form. Comparing SmtpUTF8Mailboxes consists of a domain part step and a local-part step. The comparison form for local-parts is always UTF-8. The comparison form for domain parts depends on context. While some contexts such as certificate path
与SmtpUTF8Mailbox进行等效性比较时，根据输入是否已处于比较形式，可能会在一个或两个输入上进行一些设置工作。比较SMTPUTF8邮箱包括域部分步骤和本地部分步骤。局部零件的比较表始终为UTF-8。域部分的比较形式取决于上下文。而一些上下文，如证书路径
validation in [RFC5280] specify transforming domain to A-label (Sections 7.2 and 7.5 in [RFC5280] as updated by [RFC8399]), this document recommends transforming to UTF-8 U-label instead. This reduces the likelihood of errors by reducing conversions as more implementations natively support U-label domains.
[RFC5280]中的验证指定将域转换为A标签（经[RFC8399]更新的[RFC5280]中的第7.2节和第7.5节），本文件建议改为转换为UTF-8 U标签。这通过减少转换来降低出错的可能性，因为更多的实现本机支持U标签域。
Comparison of two SmtpUTF8Mailboxes is straightforward with no setup work needed. They are considered equivalent if there is an exact octet-for-octet match. Comparison with email addresses such as internationalized email address or rfc822Name requires additional setup steps for domain part and local-part. The initial preparation for the email addresses is to remove any phrases, comments, and "<" or ">" characters. This document calls for comparison of domain labels that include non-ASCII characters to be transformed to U-labels if not already in that form. The first step is to detect use of the A-label by using Section 5.1 of [RFC5891]. Next, if necessary, transform any A-labels (US-ASCII) to U-labels (Unicode) as specified in Section 5.2 of [RFC5891]. Finally, if necessary, convert the Unicode to UTF-8 as specified in Section 3 of [RFC3629]. For ASCII NR-LDH labels, uppercase letters are converted to lowercase letters. In setup for SmtpUTF8Mailbox, the email address local-part MUST conform to the requirements of [RFC6530] and [RFC6531], including being a string in UTF-8 form. In particular, the local-part MUST NOT be transformed in any way, such as by doing case folding or normalization of any kind. The <Local-part> part of an internationalized email address is already in UTF-8. For rfc822Name, the local-part, which is IA5String (ASCII), trivially maps to UTF-8 without change. Once setup is complete, they are again compared octet for octet.
比较两个SMTPUTF8邮箱非常简单，无需进行设置工作。如果八位元匹配有一个精确的八位元，则认为它们是等价的。与电子邮件地址（如国际化电子邮件地址或rfc822Name）进行比较需要为域部分和本地部分执行额外的设置步骤。电子邮件地址的初始准备工作是删除任何短语、注释和“<”或“>”字符。本文档要求对包含非ASCII字符的域标签进行比较，以便将其转换为U型标签（如果尚未转换为U型标签）。第一步是使用[RFC5891]第5.1节检测A标签的使用。接下来，如有必要，按照[RFC5891]第5.2节的规定，将任何A标签（US-ASCII）转换为U标签（Unicode）。最后，如有必要，按照[RFC3629]第3节的规定，将Unicode转换为UTF-8。对于ASCII NR-LDH标签，大写字母转换为小写字母。在SmtpUTF8Mailbox的设置中，电子邮件地址本地部分必须符合[RFC6530]和[RFC6531]的要求，包括UTF-8格式的字符串。特别是，不得以任何方式变换局部部分，例如通过进行任何类型的大小写折叠或规范化。国际化电子邮件地址的<Local part>部分已在UTF-8中。对于rfc822Name，本地部分，即IA5String（ASCII），可以简单地映射到UTF-8，而不做任何更改。设置完成后，再次对它们进行八位字节的比较。
To summarize non-normatively, the comparison steps, including setup, are:
非规范性总结，包括设置在内的比较步骤包括：
1. If the domain contains A-labels, transform them to U-labels.
1. 如果域包含A标签，请将其转换为U标签。
2. If the domain contains ASCII NR-LDH labels, lowercase them.
2. 如果域包含ASCII NR-LDH标签，请将其小写。
3. Compare strings octet for octet for equivalence.
3. 比较字符串八位字节的等效性。
This specification expressly does not define any wildcard characters, and SmtpUTF8Mailbox comparison implementations MUST NOT interpret any characters as wildcards. Instead, to specify multiple email addresses through SmtpUTF8Mailbox, the certificate MUST use multiple subjectAltNames or issuerAltNames to explicitly carry any additional email addresses.
本规范未明确定义任何通配符，SMTPUTF8邮箱比较实现不得将任何字符解释为通配符。相反，要通过SmtpUTF8Mailbox指定多个电子邮件地址，证书必须使用多个subjectaltname或issueratnames来显式携带任何其他电子邮件地址。
This section updates Section 4.2.1.10 of [RFC5280] to extend rfc822Name name constraints to SmtpUTF8Mailbox subjectAltNames. SmtpUTF8Mailbox-aware path validators will apply name constraint comparison to the subject distinguished name and both forms of subject alternative names rfc822Name and SmtpUTF8Mailbox.
本节更新了[RFC5280]的第4.2.1.10节，将RFC822名称约束扩展到SmtpUTF8Mailbox subjectAltNames。SMTPUTF8邮箱感知路径验证器将对主题可分辨名称以及主题替代名称rfc822Name和SmtpUTF8Mailbox的两种形式应用名称约束比较。
Both rfc822Name and SmtpUTF8Mailbox subject alternative names represent the same underlying email address namespace. Since legacy CAs constrained to issue certificates for a specific set of domains would lack corresponding UTF-8 constraints, [RFC8399] updates, modifies, and extends rfc822Name name constraints defined in [RFC5280] to cover SmtpUTF8Mailbox subject alternative names. This ensures that the introduction of SmtpUTF8Mailbox does not violate existing name constraints. Since it is not valid to include non-ASCII UTF-8 characters in the local-part of rfc822Name name constraints, and since name constraints that include a local-part are rarely, if at all, used in practice, name constraints updated in [RFC8399] allow the forms that represent all addresses at a host or all mailboxes in a domain and deprecates rfc822Name name constraints that represent a particular mailbox. That is, rfc822Name constraints with a local-part SHOULD NOT be used.
rfc822Name和SMTPUTF8邮箱主题备选名称都表示相同的基础电子邮件地址命名空间。由于受约束为特定域集颁发证书的传统CA将缺少相应的UTF-8约束，[RFC8399]更新、修改和扩展[RFC5280]中定义的RFC822名称约束，以涵盖SMTPUTF8邮箱主体的备选名称。这确保了SmtpUTF8Mailbox的引入不会违反现有的名称约束。由于在RFC822名称约束的本地部分包含非ASCII UTF-8字符是无效的，并且由于包含本地部分的名称约束在实践中很少使用（如果有的话），因此在[RFC8399]中更新了名称约束允许表示主机上的所有地址或域中的所有邮箱的表单，并反对表示特定邮箱的RFC822名称约束。也就是说，不应使用带有局部零件的RFC822名称约束。
Constraint comparison with SmtpUTF8Mailbox subjectAltName starts with the setup steps defined by Section 5. Setup converts the inputs of the comparison (which is one of a subject distinguished name, an rfc822Name, or an SmtpUTF8Mailbox subjectAltName, and one of an rfc822Name name constraint) to constraint comparison form. For an rfc822Name name constraint, this will convert any domain A-labels to U-labels. For both the name constraint and the subject, this will lowercase any domain NR-LDH labels. Strip the local-part and "@" separator from each rfc822Name and SmtpUTF8Mailbox, leaving just the domain part. After setup, this follows the comparison steps defined in Section 4.2.1.10 of [RFC5280] as follows. If the resulting name constraint domain starts with a "." character, then for the name constraint to match, a suffix of the resulting subject alternative name domain MUST match the name constraint (including the leading ".") octet for octet. If the resulting name constraint domain does not start with a "." character, then for the name constraint to match, the entire resulting subject alternative name domain MUST match the name constraint octet for octet.
与SmtpUTF8Mailbox SubjectName的约束比较从第5节定义的设置步骤开始。安装程序将比较的输入（主题可分辨名称、RFC822名称或SmtpUTF8Mailbox subjectAltName中的一个，以及RFC822名称约束中的一个）转换为约束比较形式。对于rfc822Name名称约束，这将把任何域A标签转换为U标签。对于名称约束和主题，这将降低任何域NR-LDH标签的大小写。从每个RFC822名称和SMTPUTF8邮箱中去掉本地部分和“@”分隔符，只留下域部分。设置后，遵循[RFC5280]第4.2.1.10节中定义的比较步骤，如下所示。如果生成的名称约束域以“.”字符开头，则要使名称约束匹配，生成的主题替代名称域的后缀必须与名称约束（包括前导的“.”八位字节）匹配。如果生成的名称约束域不以“.”字符开头，则要使名称约束匹配，整个生成的主题替代名称域必须与名称约束的八位字节对应八位字节匹配。
Certificate Authorities that wish to issue CA certificates with email address name constraints MUST use rfc822Name subject alternative names only. These MUST be IDNA2008-conformant names with no mappings and with non-ASCII domains encoded in A-labels only.
希望颁发具有电子邮件地址名称约束的CA证书的证书颁发机构必须仅使用RFC822名称使用者替代名称。这些名称必须是IDNA2008一致的名称，没有映射，并且只有A标签编码的非ASCII域。
The name constraint requirement with SmtpUTF8Mailbox subject alternative name is illustrated in the non-normative diagram in Figure 1. The first example (1) illustrates a permitted rfc822Name ASCII-only host name name constraint and the corresponding valid rfc822Name subjectAltName and SmtpUTF8Mailbox subjectAltName email addresses. The second example (2) illustrates a permitted rfc822Name host name name constraint with A-label, and the corresponding valid rfc822Name subjectAltName and SmtpUTF8Mailbox subjectAltName email addresses. Note that an email address with ASCII-only local-part is encoded as rfc822Name despite also having Unicode present in the domain.
图1中的非规范性图表说明了SmtpUTF8Mailbox subject备用名称的名称约束要求。第一个示例（1）说明了允许的rfc822Name ASCII仅主机名约束以及相应的有效rfc822Name subjectAltName和SmtpUTF8Mailbox subjectAltName电子邮件地址。第二个示例（2）说明了允许的带有a标签的rfc822Name主机名约束，以及相应的有效rfc822Name subjectAltName和SmtpUTF8Mailbox subjectAltName电子邮件地址。请注意，仅包含ASCII本地部分的电子邮件地址被编码为rfc822Name，尽管域中还存在Unicode。
+-------------------------------------------------------------------+
| Root CA Cert |
+-------------------------------------------------------------------+
|
v
+-------------------------------------------------------------------+
| Intermediate CA Cert |
| Permitted |
| rfc822Name: elementary.school.example.com (1) |
| |
| rfc822Name: xn--pss25c.example.com (2) |
| |
+-------------------------------------------------------------------+
|
v
+-------------------------------------------------------------------+
| Entity Cert (w/explicitly permitted subjects) |
| SubjectAltName Extension |
| rfc822Name: student@elemenary.school.example.com (1) |
| SmtpUTF8Mailbox: u+5B66u+751F@elementary.school.example.com |
| (1) |
| |
| rfc822Name: student@xn--pss25c.example.com (2) |
| SmtpUTF8Mailbox: u+533Bu+751F@u+5927u+5B66.example.com (2) |
| |
+-------------------------------------------------------------------+
+-------------------------------------------------------------------+
| Root CA Cert |
+-------------------------------------------------------------------+
|
v
+-------------------------------------------------------------------+
| Intermediate CA Cert |
| Permitted |
| rfc822Name: elementary.school.example.com (1) |
| |
| rfc822Name: xn--pss25c.example.com (2) |
| |
+-------------------------------------------------------------------+
|
v
+-------------------------------------------------------------------+
| Entity Cert (w/explicitly permitted subjects) |
| SubjectAltName Extension |
| rfc822Name: student@elemenary.school.example.com (1) |
| SmtpUTF8Mailbox: u+5B66u+751F@elementary.school.example.com |
| (1) |
| |
| rfc822Name: student@xn--pss25c.example.com (2) |
| SmtpUTF8Mailbox: u+533Bu+751F@u+5927u+5B66.example.com (2) |
| |
+-------------------------------------------------------------------+
Figure 1: Name Constraints with SmtpUTF8Name and rfc822Name
图1:SmtpUTF8Name和rfc822Name的名称约束
Use of SmtpUTF8Mailbox for certificate subjectAltName (and issuerAltName) will incur many of the same security considerations as in Section 8 in [RFC5280], but it introduces a new issue by permitting non-ASCII characters in the email address local-part. This issue, as mentioned in Section 4.4 of [RFC5890] and in Section 4
将SmtpUTF8Mailbox用于证书主题名称（和ISSUERATNAME）将引起许多与[RFC5280]第8节中相同的安全注意事项，但它通过允许电子邮件地址本地部分使用非ASCII字符引入了一个新问题。该问题，如[RFC5890]第4.4节和第4节所述
of [RFC6532], is that use of Unicode introduces the risk of visually similar and identical characters that can be exploited to deceive the recipient. The former document references some means to mitigate against these attacks. See [WEBER] for more background on security issues with Unicode.
[RFC6532]的一个特点是，使用Unicode会带来视觉上相似和相同的字符的风险，这些字符可能被用来欺骗收件人。前一个文档引用了一些缓解这些攻击的方法。有关Unicode安全问题的更多背景信息，请参见[WEBER]。
As described in Section 3 and the ASN.1 module identifier defined in Appendix A, IANA has assigned the values described here.
如第3节所述和附录A中定义的ASN.1模块标识符，IANA已分配此处所述的值。
o For the LAMPS-EaiAddresses-2016 ASN.1 module, IANA has registered value 92 for "id-mod-lamps-eai-addresses-2016" in the "SMI Security for PKIX Module Identifier" (1.3.6.1.5.5.7.0) registry.
o 对于LAMPS-eai-2016 ASN.1模块，IANA在“PKIX模块标识符的SMI安全性”（1.3.6.1.5.5.7.0）注册表中注册了“id-mod-LAMPS-eai-addresses-2016”的值92。
o For the SmtpUTF8Mailbox otherName, IANA has registered value 9 for id-on-SmtpUTF8Mailbox in the "SMI Security for PKIX Other Name Forms" (1.3.6.1.5.5.7.8) registry.
o 对于SmtpUTF8Mailbox otherName，IANA在“SMI Security For PKIX Other Name Forms”（1.3.6.1.5.5.7.8）注册表中为id-on-SmtpUTF8Mailbox注册了值9。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<https://www.rfc-editor.org/info/rfc2119>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003, <https://www.rfc-editor.org/info/rfc3629>.
[RFC3629]Yergeau，F.，“UTF-8，ISO 10646的转换格式”，STD 63，RFC 3629，DOI 10.17487/RFC3629，2003年11月<https://www.rfc-editor.org/info/rfc3629>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008, <https://www.rfc-editor.org/info/rfc5234>.
[RFC5234]Crocker，D.，Ed.和P.Overell，“语法规范的扩充BNF:ABNF”，STD 68，RFC 5234，DOI 10.17487/RFC5234，2008年1月<https://www.rfc-editor.org/info/rfc5234>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, <https://www.rfc-editor.org/info/rfc5280>.
[RFC5280]Cooper，D.，Santesson，S.，Farrell，S.，Boeyen，S.，Housley，R.，和W.Polk，“Internet X.509公钥基础设施证书和证书撤销列表（CRL）配置文件”，RFC 5280，DOI 10.17487/RFC5280，2008年5月<https://www.rfc-editor.org/info/rfc5280>.
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, DOI 10.17487/RFC5321, October 2008, <https://www.rfc-editor.org/info/rfc5321>.
[RFC5321]Klensin，J.，“简单邮件传输协议”，RFC 5321DOI 10.17487/RFC5321，2008年10月<https://www.rfc-editor.org/info/rfc5321>.
[RFC5890] Klensin, J., "Internationalized Domain Names for Applications (IDNA): Definitions and Document Framework", RFC 5890, DOI 10.17487/RFC5890, August 2010, <https://www.rfc-editor.org/info/rfc5890>.
[RFC5890]Klensin，J.，“应用程序的国际化域名（IDNA）：定义和文档框架”，RFC 5890，DOI 10.17487/RFC5890，2010年8月<https://www.rfc-editor.org/info/rfc5890>.
[RFC5891] Klensin, J., "Internationalized Domain Names in Applications (IDNA): Protocol", RFC 5891, DOI 10.17487/RFC5891, August 2010, <https://www.rfc-editor.org/info/rfc5891>.
[RFC5891]Klensin，J.，“应用程序中的国际化域名（IDNA）：协议”，RFC 5891，DOI 10.17487/RFC5891，2010年8月<https://www.rfc-editor.org/info/rfc5891>.
[RFC6530] Klensin, J. and Y. Ko, "Overview and Framework for Internationalized Email", RFC 6530, DOI 10.17487/RFC6530, February 2012, <https://www.rfc-editor.org/info/rfc6530>.
[RFC6530]Klensin，J.和Y.Ko，“国际化电子邮件的概述和框架”，RFC 6530，DOI 10.17487/RFC6530，2012年2月<https://www.rfc-editor.org/info/rfc6530>.
[RFC6531] Yao, J. and W. Mao, "SMTP Extension for Internationalized Email", RFC 6531, DOI 10.17487/RFC6531, February 2012, <https://www.rfc-editor.org/info/rfc6531>.
[RFC6531]Yao，J.和W.Mao，“国际化电子邮件的SMTP扩展”，RFC 6531，DOI 10.17487/RFC653112012年2月<https://www.rfc-editor.org/info/rfc6531>.
[RFC6532] Yang, A., Steele, S., and N. Freed, "Internationalized Email Headers", RFC 6532, DOI 10.17487/RFC6532, February 2012, <https://www.rfc-editor.org/info/rfc6532>.
[RFC6532]Yang，A.，Steele，S.，和N.Freed，“国际化电子邮件头”，RFC 6532，DOI 10.17487/RFC6532，2012年2月<https://www.rfc-editor.org/info/rfc6532>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[RFC8399] Housley, R., "Internationalization Updates to RFC 5280", RFC 8399, DOI 10.17487/RFC8399, May 2018, <https://www.rfc-editor.org/info/rfc8399>.
[RFC8399]Housley，R.，“RFC 5280的国际化更新”，RFC 8399，DOI 10.17487/RFC8399，2018年5月<https://www.rfc-editor.org/info/rfc8399>.
[RFC5912] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)", RFC 5912, DOI 10.17487/RFC5912, June 2010, <https://www.rfc-editor.org/info/rfc5912>.
[RFC5912]Hoffman，P.和J.Schaad，“使用X.509（PKIX）的公钥基础设施的新ASN.1模块”，RFC 5912，DOI 10.17487/RFC5912，2010年6月<https://www.rfc-editor.org/info/rfc5912>.
[WEBER] Weber, C., "Attacking Software Globalization", March 2010, <https://www.lookout.net/files/ Chris_Weber_Character%20Transformations%20v1.7_IUC33.pdf>.
[WEBER]WEBER，C.，“攻击软件全球化”，2010年3月<https://www.lookout.net/files/ Chris_Weber_字符%20v1.7\u IUC33.pdf>。
The following ASN.1 module normatively specifies the SmtpUTF8Mailbox structure. This specification uses the ASN.1 definitions from [RFC5912] with the 2002 ASN.1 notation used in that document. [RFC5912] updates normative documents using older ASN.1 notation.
以下ASN.1模块规范性地指定了SMTPUTF8邮箱结构。本规范使用[RFC5912]中的ASN.1定义以及该文件中使用的2002 ASN.1符号。[RFC5912]使用较旧的ASN.1符号更新规范性文件。
LAMPS-EaiAddresses-2016
{ iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-lamps-eai-addresses-2016(92) }
LAMPS-EaiAddresses-2016
{ iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-lamps-eai-addresses-2016(92) }
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
DEFINITIONS IMPLICIT TAGS ::=
BEGIN
IMPORTS
OTHER-NAME
FROM PKIX1Implicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59) }
IMPORTS
OTHER-NAME
FROM PKIX1Implicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59) }
id-pkix
FROM PKIX1Explicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-explicit-02(51) } ;
id-pkix
FROM PKIX1Explicit-2009
{ iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-explicit-02(51) } ;
--
-- otherName carries additional name types for subjectAltName,
-- issuerAltName, and other uses of GeneralNames.
--
--
-- otherName carries additional name types for subjectAltName,
-- issuerAltName, and other uses of GeneralNames.
--
id-on OBJECT IDENTIFIER ::= { id-pkix 8 }
id-on OBJECT IDENTIFIER ::= { id-pkix 8 }
SmtpUtf8OtherNames OTHER-NAME ::= { on-SmtpUTF8Mailbox, ... }
SmtpUtf8OtherNames OTHER-NAME ::= { on-SmtpUTF8Mailbox, ... }
on-SmtpUTF8Mailbox OTHER-NAME ::= {
SmtpUTF8Mailbox IDENTIFIED BY id-on-SmtpUTF8Mailbox
}
on-SmtpUTF8Mailbox OTHER-NAME ::= {
SmtpUTF8Mailbox IDENTIFIED BY id-on-SmtpUTF8Mailbox
}
id-on-SmtpUTF8Mailbox OBJECT IDENTIFIER ::= { id-on 9 }
id-on-SmtpUTF8Mailbox OBJECT IDENTIFIER ::= { id-on 9 }
SmtpUTF8Mailbox ::= UTF8String (SIZE (1..MAX))
-- SmtpUTF8Mailbox conforms to Mailbox as specified
-- in Section 3.3 of RFC 6531.
SmtpUTF8Mailbox ::= UTF8String (SIZE (1..MAX))
-- SmtpUTF8Mailbox conforms to Mailbox as specified
-- in Section 3.3 of RFC 6531.
END
终止
This non-normative example demonstrates using SmtpUTF8Mailbox as an otherName in GeneralName to encode the email address "u+8001u+5E2B@example.com".
此非规范性示例演示如何使用SmtpUTF8Mailbox作为GeneralName中的其他名称对电子邮件地址“u+8001u”进行编码+5E2B@example.com".
The hexadecimal DER encoding of the email address is: A022060A 2B060105 05070012 0809A014 0C12E880 81E5B8AB 40657861 6D706C65 2E636F6D
电子邮件地址的十六进制DER编码为：A022060A 2B060105 05070012 0809A014 0C12E880 81E5B8AB 40657861 6D706C65 2E636F6D
The text decoding is:
0 34: [0] {
2 10: OBJECT IDENTIFIER '1 3 6 1 5 5 7 0 18 8 9'
14 20: [0] {
16 18: UTF8String '..@example.com'
: }
: }
The text decoding is:
0 34: [0] {
2 10: OBJECT IDENTIFIER '1 3 6 1 5 5 7 0 18 8 9'
14 20: [0] {
16 18: UTF8String '..@example.com'
: }
: }
Figure 2
图2
The example was encoded on the OSS Nokalva ASN.1 Playground and the above text decoding is an output of Peter Gutmann's "dumpasn1" program.
该示例是在OSS Nokalva ASN.1游乐场上编码的，上面的文本解码是Peter Gutmann的“dumpasn1”程序的输出。
Acknowledgements
致谢
Thank you to Magnus Nystrom for motivating this document. Thanks to Russ Housley, Nicolas Lidzborski, Laetitia Baudoin, Ryan Sleevi, Sean Leonard, Sean Turner, John Levine, and Patrik Falstrom for their feedback. Also special thanks to John Klensin for his valuable input on internationalization, Unicode, and ABNF formatting; to Jim Schaad for his help with the ASN.1 example and his helpful feedback; and especially to Viktor Dukhovni for helping us with name constraints and his many detailed document reviews.
感谢Magnus Nystrom对本文件的激励。感谢Russ Housley、Nicolas Lidzborski、Laetitia Baudoin、Ryan Slovi、Sean Leonard、Sean Turner、John Levine和Patrik Falstrom的反馈。还特别感谢John Klensin在国际化、Unicode和ABNF格式方面的宝贵投入；感谢Jim Schaad对ASN.1示例的帮助和他有用的反馈；尤其要感谢维克托·杜霍夫尼，他帮助我们解决了名称限制和他对许多详细文档的审查。
Authors' Addresses
作者地址
Alexey Melnikov (editor) Isode Ltd 14 Castle Mews Hampton, Middlesex TW12 2NP United Kingdom
Alexey Melnikov（编辑）Isode有限公司14 Castle Mews Hampton，米德尔塞克斯TW12 2NP英国
Email: Alexey.Melnikov@isode.com
Email: Alexey.Melnikov@isode.com
Weihaw Chuang (editor) Google, Inc. 1600 Amphitheater Parkway Mountain View, CA 94043 United States of America
庄维豪（编辑）谷歌有限公司1600圆形剧场公园山景，加利福尼亚州94043
Email: weihaw@google.com
Email: weihaw@google.com