Internet Engineering Task Force (IETF)                        P. Wouters
Request for Comments: 7929                                       Red Hat
Category: Experimental                                       August 2016
ISSN: 2070-1721
        
Internet Engineering Task Force (IETF)                        P. Wouters
Request for Comments: 7929                                       Red Hat
Category: Experimental                                       August 2016
ISSN: 2070-1721
        

DNS-Based Authentication of Named Entities (DANE) Bindings for OpenPGP

基于DNS的OpenPGP命名实体(DANE)绑定身份验证

Abstract

摘要

OpenPGP is a message format for email (and file) encryption that lacks a standardized lookup mechanism to securely obtain OpenPGP public keys. DNS-Based Authentication of Named Entities (DANE) is a method for publishing public keys in DNS. This document specifies a DANE method for publishing and locating OpenPGP public keys in DNS for a specific email address using a new OPENPGPKEY DNS resource record. Security is provided via Secure DNS, however the OPENPGPKEY record is not a replacement for verification of authenticity via the "web of trust" or manual verification. The OPENPGPKEY record can be used to encrypt an email that would otherwise have to be sent unencrypted.

OpenPGP是一种用于电子邮件(和文件)加密的消息格式,缺乏安全获取OpenPGP公钥的标准化查找机制。基于DNS的命名实体身份验证(DANE)是一种在DNS中发布公钥的方法。本文档指定了使用新的OPENPGPKEY DNS资源记录在DNS中发布和定位特定电子邮件地址的OpenPGP公钥的DANE方法。安全性是通过安全DNS提供的,但是OPENPGPKEY记录不能替代通过“信任网”或手动验证的真实性验证。OPENPGPKEY记录可用于加密电子邮件,否则必须以未加密的方式发送。

Status of This Memo

关于下段备忘

This document is not an Internet Standards Track specification; it is published for examination, experimental implementation, and evaluation.

本文件不是互联网标准跟踪规范;它是为检查、实验实施和评估而发布的。

This document defines an Experimental Protocol for the Internet community. 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 7841.

本文档为互联网社区定义了一个实验协议。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。并非IESG批准的所有文件都适用于任何级别的互联网标准;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 http://www.rfc-editor.org/info/rfc7929.

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http://www.rfc-editor.org/info/rfc7929.

Copyright Notice

版权公告

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

版权所有(c)2016 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 (http://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(http://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  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Experiment Goal . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  The OPENPGPKEY Resource Record  . . . . . . . . . . . . . . .   5
     2.1.  The OPENPGPKEY RDATA Component  . . . . . . . . . . . . .   6
       2.1.1.  The OPENPGPKEY RDATA Content  . . . . . . . . . . . .   6
       2.1.2.  Reducing the Transferable Public Key Size . . . . . .   7
     2.2.  The OPENPGPKEY RDATA Wire Format  . . . . . . . . . . . .   7
     2.3.  The OPENPGPKEY RDATA Presentation Format  . . . . . . . .   7
   3.  Location of the OPENPGPKEY Record . . . . . . . . . . . . . .   8
   4.  Email Address Variants and Internationalization
       Considerations  . . . . . . . . . . . . . . . . . . . . . . .   9
   5.  Application Use of OPENPGPKEY . . . . . . . . . . . . . . . .  10
     5.1.  Obtaining an OpenPGP Key for a Specific Email Address . .  10
     5.2.  Confirming that an OpenPGP Key is Current . . . . . . . .  10
     5.3.  Public Key UIDs and Query Names . . . . . . . . . . . . .  10
   6.  OpenPGP Key Size and DNS  . . . . . . . . . . . . . . . . . .  11
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
     7.1.  MTA Behavior  . . . . . . . . . . . . . . . . . . . . . .  12
     7.2.  MUA Behavior  . . . . . . . . . . . . . . . . . . . . . .  13
     7.3.  Response Size . . . . . . . . . . . . . . . . . . . . . .  14
     7.4.  Email Address Information Leak  . . . . . . . . . . . . .  14
     7.5.  Storage of OPENPGPKEY Data  . . . . . . . . . . . . . . .  14
     7.6.  Security of OpenPGP versus DNSSEC . . . . . . . . . . . .  15
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
     8.1.  OPENPGPKEY RRtype . . . . . . . . . . . . . . . . . . . .  15
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  16
   Appendix A.  Generating OPENPGPKEY Records  . . . . . . . . . . .  18
   Appendix B.  OPENPGPKEY IANA Template . . . . . . . . . . . . . .  19
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  20
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  20
        
   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Experiment Goal . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  The OPENPGPKEY Resource Record  . . . . . . . . . . . . . . .   5
     2.1.  The OPENPGPKEY RDATA Component  . . . . . . . . . . . . .   6
       2.1.1.  The OPENPGPKEY RDATA Content  . . . . . . . . . . . .   6
       2.1.2.  Reducing the Transferable Public Key Size . . . . . .   7
     2.2.  The OPENPGPKEY RDATA Wire Format  . . . . . . . . . . . .   7
     2.3.  The OPENPGPKEY RDATA Presentation Format  . . . . . . . .   7
   3.  Location of the OPENPGPKEY Record . . . . . . . . . . . . . .   8
   4.  Email Address Variants and Internationalization
       Considerations  . . . . . . . . . . . . . . . . . . . . . . .   9
   5.  Application Use of OPENPGPKEY . . . . . . . . . . . . . . . .  10
     5.1.  Obtaining an OpenPGP Key for a Specific Email Address . .  10
     5.2.  Confirming that an OpenPGP Key is Current . . . . . . . .  10
     5.3.  Public Key UIDs and Query Names . . . . . . . . . . . . .  10
   6.  OpenPGP Key Size and DNS  . . . . . . . . . . . . . . . . . .  11
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
     7.1.  MTA Behavior  . . . . . . . . . . . . . . . . . . . . . .  12
     7.2.  MUA Behavior  . . . . . . . . . . . . . . . . . . . . . .  13
     7.3.  Response Size . . . . . . . . . . . . . . . . . . . . . .  14
     7.4.  Email Address Information Leak  . . . . . . . . . . . . .  14
     7.5.  Storage of OPENPGPKEY Data  . . . . . . . . . . . . . . .  14
     7.6.  Security of OpenPGP versus DNSSEC . . . . . . . . . . . .  15
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
     8.1.  OPENPGPKEY RRtype . . . . . . . . . . . . . . . . . . . .  15
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  16
   Appendix A.  Generating OPENPGPKEY Records  . . . . . . . . . . .  18
   Appendix B.  OPENPGPKEY IANA Template . . . . . . . . . . . . . .  19
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  20
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  20
        
1. Introduction
1. 介绍

OpenPGP [RFC4880] public keys are used to encrypt or sign email messages and files. To encrypt an email message, or verify a sender's OpenPGP signature, the email client Mail User Agent (MUA) or the email server Mail Transfer Agent (MTA) needs to locate the recipient's OpenPGP public key.

OpenPGP[RFC4880]公钥用于加密或签名电子邮件和文件。要加密电子邮件或验证发件人的OpenPGP签名,电子邮件客户端邮件用户代理(MUA)或电子邮件服务器邮件传输代理(MTA)需要找到收件人的OpenPGP公钥。

OpenPGP clients have relied on centralized "well-known" key servers that are accessed using the HTTP Keyserver Protocol [HKP]. Alternatively, users need to manually browse a variety of different front-end websites. These key servers do not require a confirmation of the email address used in the User ID (UID) of the uploaded OpenPGP public key. Attackers can -- and have -- uploaded rogue public keys with other people's email addresses to these key servers.

OpenPGP客户端依赖于使用HTTP密钥服务器协议[HKP]访问的集中式“知名”密钥服务器。或者,用户需要手动浏览各种不同的前端网站。这些密钥服务器不需要确认上传的OpenPGP公钥的用户ID(UID)中使用的电子邮件地址。攻击者可以——并且已经——将带有他人电子邮件地址的恶意公钥上传到这些密钥服务器。

Once uploaded, public keys cannot be deleted. People who did not pre-sign a key revocation can never remove their OpenPGP public key from these key servers once they have lost access to their private key. This results in receiving encrypted email that cannot be decrypted.

一旦上传,公钥就不能被删除。未对密钥撤销进行预签名的人员一旦失去对其私钥的访问权限,就永远无法从这些密钥服务器中删除其OpenPGP公钥。这将导致接收无法解密的加密电子邮件。

Therefore, these key servers are not well suited to support MUAs and MTAs to automatically encrypt email -- especially in the absence of an interactive user.

因此,这些密钥服务器不太适合支持MUA和MTA自动加密电子邮件,特别是在没有交互用户的情况下。

This document describes a mechanism to associate a user's OpenPGP public key with their email address, using the OPENPGPKEY DNS RRtype. These records are published in the DNS zone of the user's email address. If the user loses their private key, the OPENPGPKEY DNS record can simply be updated or removed from the zone.

本文档描述了使用OPENPGPKEY DNS RRtype将用户的OpenPGP公钥与其电子邮件地址关联的机制。这些记录发布在用户电子邮件地址的DNS区域中。如果用户丢失了私钥,只需更新OPENPGPKEY DNS记录或将其从区域中删除即可。

The OPENPGPKEY data is secured using Secure DNS [RFC4035].

OPENPGPKEY数据使用安全DNS[RFC4035]进行保护。

The main goal of the OPENPGPKEY resource record is to stop passive attacks against plaintext emails. While it can also thwart some active attacks (such as people uploading rogue keys to key servers in the hopes that others will encrypt to these rogue keys), this resource record is not a replacement for verifying OpenPGP public keys via the "web of trust" signatures, or manually via a fingerprint verification.

OPENPGPKEY资源记录的主要目标是阻止对明文电子邮件的被动攻击。虽然它还可以阻止某些主动攻击(例如,人们将恶意密钥上传到密钥服务器,希望其他人将加密到这些恶意密钥),但此资源记录不能替代通过“信任网”签名或通过指纹验证手动验证OpenPGP公钥。

1.1. Experiment Goal
1.1. 实验目标

This specification is one experiment in improving access to public keys for end-to-end email security. There are a range of ways in which this can reasonably be done for OpenPGP or S/MIME, for example, using the DNS, or SMTP, or HTTP. Proposals for each of these have

本规范是一项旨在提高端到端电子邮件安全性的公钥访问能力的实验。对于OpenPGP或S/MIME,有一系列合理的方法可以做到这一点,例如,使用DNS、SMTP或HTTP。对每一项建议都提出了建议

been made with various levels of support in terms of implementation and deployment. For each such experiment, specifications such as this will enable experiments to be carried out that may succeed or that may uncover technical or other impediments to large- or small-scale deployments. The IETF encourages those implementing and deploying such experiments to publicly document their experiences so that future specifications in this space can benefit.

在实施和部署方面得到了各级支持。对于每一个这样的实验,像这样的规范将使实验能够成功进行,或者可能发现技术或其他阻碍大规模或小型部署的障碍。IETF鼓励那些实施和部署此类实验的人公开记录他们的经验,以便该领域的未来规范能够受益。

This document defines an RRtype whose use is Experimental. The goal of the experiment is to see whether encrypted email usage will increase if an automated discovery method is available to MTAs and MUAs to help the end user with email encryption key management.

本文档定义了一个RRtype,其用途是实验性的。实验的目标是,如果MTA和MUA可以使用自动发现方法来帮助最终用户管理电子邮件加密密钥,那么加密电子邮件的使用是否会增加。

It is unclear if this RRtype will scale to some of the larger email service deployments. Concerns have been raised about the size of the OPENPGPKEY record and the size of the resulting DNS zone files. This experiment hopefully will give the working group some insight into whether or not this is a problem.

目前尚不清楚这种RRtype是否会扩展到一些较大的电子邮件服务部署中。OPENPGPKEY记录的大小以及生成的DNS区域文件的大小引起了关注。希望这项实验能让工作组对这是否是一个问题有所了解。

If the experiment is successful, it is expected that the findings of the experiment will result in an updated document for standards track approval.

如果试验成功,预计试验结果将产生一份更新的文件,供标准跟踪批准。

The OPENPGPKEY RRtype somewhat resembles the generic CERT record defined in [RFC4398]. However, the CERT record uses sub-typing with many different types of keys and certificates. It is suspected that its general application of very different protocols (PKIX versus OpenPGP) has been the cause for lack of implementation and deployment. Furthermore, the CERT record uses sub-typing, which is now considered to be a bad idea for DNS.

OPENPGPKEY RRtype在某种程度上类似于[RFC4398]中定义的通用证书记录。但是,CERT记录使用具有许多不同类型的密钥和证书的子类型。人们怀疑,它对非常不同的协议(PKIX和OpenPGP)的普遍应用是缺乏实现和部署的原因。此外,证书记录使用子类型,这现在被认为是DNS的一个坏主意。

1.2. Terminology
1.2. 术语

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 [RFC2119].

本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。

This document also makes use of standard DNSSEC and DANE terminology. See DNSSEC [RFC4033], [RFC4034], [RFC4035], and DANE [RFC6698] for these terms.

本文件还使用了标准DNSSEC和丹麦术语。有关这些条款,请参见DNSSEC[RFC4033]、[RFC4034]、[RFC4035]和丹麦[RFC6698]。

2. The OPENPGPKEY Resource Record
2. OPENPGPKEY资源记录

The OPENPGPKEY DNS resource record (RR) is used to associate an end entity OpenPGP Transferable Public Key (see Section 11.1 of [RFC4880]) with an email address, thus forming an "OpenPGP public key association". A user that wishes to specify more than one OpenPGP key, for example, because they are transitioning to a newer stronger

OPENPGPKEY DNS资源记录(RR)用于将终端实体OpenPGP可转移公钥(参见[RFC4880]第11.1节)与电子邮件地址关联,从而形成“OpenPGP公钥关联”。例如,希望指定多个OpenPGP密钥的用户,因为他们正在转换到较新的密钥

key, can do so by adding multiple OPENPGPKEY records. A single OPENPGPKEY DNS record MUST only contain one OpenPGP key.

键,可以通过添加多个OPENPGPKEY记录来实现。单个OPENPGPKEY DNS记录必须仅包含一个OpenPGP密钥。

The type value allocated for the OPENPGPKEY RR type is 61. The OPENPGPKEY RR is class independent.

为OPENPGPKEY RR类型分配的类型值为61。OPENPGPKEY RR是独立于类的。

2.1. The OPENPGPKEY RDATA Component
2.1. OPENPGPKEY RDATA组件

The RDATA portion of an OPENPGPKEY resource record contains a single value consisting of a Transferable Public Key formatted as specified in [RFC4880].

OPENPGPKEY资源记录的RDATA部分包含一个值,该值由[RFC4880]中指定格式的可转移公钥组成。

2.1.1. The OPENPGPKEY RDATA Content
2.1.1. OPENPGPKEY RDATA内容

An OpenPGP Transferable Public Key can be arbitrarily large. DNS records are limited in size. When creating OPENPGPKEY DNS records, the OpenPGP Transferable Public Key should be filtered to only contain appropriate and useful data. At a minimum, an OPENPGPKEY Transferable Public Key for the user hugh@example.com should contain:

OpenPGP可转移公钥可以任意大。DNS记录的大小有限。创建OPENPGPKEY DNS记录时,应过滤OpenPGP可转移公钥,使其仅包含适当和有用的数据。至少为用户提供一个OPENPGPKEY可转移公钥hugh@example.com应包括:

o The primary key X o One User ID Y, which SHOULD match 'hugh@example.com' o Self-signature from X, binding X to Y

o 主键X o一个用户ID Y,应该匹配'hugh@example.com'o来自X的自签名,将X绑定到Y

If the primary key is not encryption-capable, at least one relevant subkey should be included, resulting in an OPENPGPKEY Transferable Public Key containing:

如果主密钥不支持加密,则应至少包含一个相关子密钥,从而生成包含以下内容的OPENPGPKEY可转移公钥:

o The primary key X o One User ID Y, which SHOULD match 'hugh@example.com' o Self-signature from X, binding X to Y o Encryption-capable subkey Z o Self-signature from X, binding Z to X o (Other subkeys, if relevant)

o 主键X o一个用户ID Y,应该匹配'hugh@example.com'o来自X的自签名,将X绑定到Y o支持加密的子密钥Z o来自X的自签名,将Z绑定到X o(其他子密钥,如果相关)

The user can also elect to add a few third-party certifications, which they believe would be helpful for validation in the traditional "web of trust". The resulting OPENPGPKEY Transferable Public Key would then look like:

用户还可以选择添加一些第三方认证,他们认为这将有助于在传统的“信任网”中进行验证。由此产生的OPENPGPKEY可转移公钥如下所示:

o The primary key X o One User ID Y, which SHOULD match 'hugh@example.com' o Self-signature from X, binding X to Y o Third-party certification from V, binding Y to X o (Other third-party certifications, if relevant) o Encryption-capable subkey Z o Self-signature from X, binding Z to X o (Other subkeys, if relevant)

o 主键X o一个用户ID Y,应该匹配'hugh@example.com'o来自X的自签名,将X绑定到Y o来自V的第三方认证,将Y绑定到X o(其他第三方认证,如果相关)o支持加密的子密钥Z o来自X的自签名,将Z绑定到X o(其他子密钥,如果相关)

2.1.2. Reducing the Transferable Public Key Size
2.1.2. 减小可转移公钥的大小

When preparing a Transferable Public Key for a specific OPENPGPKEY RDATA format with the goal of minimizing certificate size, a user would typically want to:

当为特定OPENPGPKEY RDATA格式准备可转移公钥以最小化证书大小时,用户通常希望:

o Where one User ID from the certifications matches the looked-up address, strip away non-matching User IDs and any associated certifications (self-signatures or third-party certifications).

o 如果证书中的一个用户ID与查找的地址匹配,则去掉不匹配的用户ID和任何相关证书(自签名或第三方证书)。

o Strip away all User Attribute packets and associated certifications.

o 去掉所有用户属性包和相关证书。

o Strip away all expired subkeys. The user may want to keep revoked subkeys if these were revoked prior to their preferred expiration time to ensure that correspondents know about these earlier than expected revocations.

o 去掉所有过期的子键。如果在首选过期时间之前撤销了已撤销的子密钥,则用户可能希望保留这些子密钥,以确保通信员早于预期的撤销时间知道这些子密钥。

o Strip away all but the most recent self-signature for the remaining User IDs and subkeys.

o 除去剩余用户ID和子密钥的所有自签名(最近的自签名除外)。

o Optionally strip away any uninteresting or unimportant third-party User ID certifications. This is a value judgment by the user that is difficult to automate. At the very least, expired and superseded third-party certifications should be stripped out. The user should attempt to keep the most recent and most well-connected certifications in the "web of trust" in their Transferable Public Key.

o 有选择地去除任何无趣或不重要的第三方用户ID认证。这是用户难以自动执行的价值判断。至少,过期和被取代的第三方认证应该被删除。用户应尝试在其可转让公钥中保存“信任网”中的最新和连接最紧密的证书。

2.2. The OPENPGPKEY RDATA Wire Format
2.2. OPENPGPKEY RDATA导线格式

The RDATA Wire Format consists of a single OpenPGP Transferable Public Key as defined in Section 11.1 of [RFC4880]. Note that this format is without ASCII armor or base64 encoding.

RDATA Wire格式由[RFC4880]第11.1节中定义的单个OpenPGP可转移公钥组成。请注意,此格式没有ASCII铠装或base64编码。

2.3. The OPENPGPKEY RDATA Presentation Format
2.3. OPENPGPKEY RDATA表示格式

The RDATA Presentation Format, as visible in master files [RFC1035], consists of a single OpenPGP Transferable Public Key as defined in Section 11.1 of [RFC4880] encoded in base64 as defined in Section 4 of [RFC4648].

主文件[RFC1035]中可见的RDATA表示格式由[RFC4880]第11.1节中定义的单个OpenPGP可转移公钥组成,该公钥编码为[RFC4648]第4节中定义的base64。

3. Location of the OPENPGPKEY Record
3. OPENPGPKEY记录的位置

The DNS does not allow the use of all characters that are supported in the "local-part" of email addresses as defined in [RFC5322] and [RFC6530]. Therefore, email addresses are mapped into DNS using the following method:

DNS不允许使用[RFC5322]和[RFC6530]中定义的电子邮件地址“本地部分”中支持的所有字符。因此,使用以下方法将电子邮件地址映射到DNS:

1. The "left-hand side" of the email address, called the "local-part" in both the mail message format definition [RFC5322] and in the specification for internationalized email [RFC6530]) is encoded in UTF-8 (or its subset ASCII). If the local-part is written in another charset, it MUST be converted to UTF-8.

1. 电子邮件地址的“左侧”,在邮件消息格式定义[RFC5322]和国际化电子邮件规范[RFC6530]中都称为“本地部分”,用UTF-8(或其子集ASCII)编码。如果本地部分写入另一个字符集,则必须将其转换为UTF-8。

2. The local-part is first canonicalized using the following rules. If the local-part is unquoted, any comments and/or folding whitespace (CFWS) around dots (".") is removed. Any enclosing double quotes are removed. Any literal quoting is removed.

2. 首先使用以下规则规范化本地部分。如果本地部分没有引号,则删除点(“.”)周围的任何注释和/或折叠空格(CFW)。所有包含的双引号都将被删除。删除任何文字引用。

3. If the local-part contains any non-ASCII characters, it SHOULD be normalized using the Unicode Normalization Form C from [Unicode90]. Recommended normalization rules can be found in Section 10.1 of [RFC6530].

3. 如果本地部分包含任何非ASCII字符,则应使用[Unicode90]中的Unicode规范化表单C对其进行规范化。建议的规范化规则见[RFC6530]第10.1节。

4. The local-part is hashed using the SHA2-256 [RFC5754] algorithm, with the hash truncated to 28 octets and represented in its hexadecimal representation, to become the left-most label in the prepared domain name.

4. 使用SHA2-256[RFC5754]算法对本地部分进行散列,散列被截断为28个八位字节,并以十六进制表示,成为准备好的域名中最左边的标签。

5. The string "_openpgpkey" becomes the second left-most label in the prepared domain name.

5. 字符串“_openpgpkey”成为准备好的域名中第二个最左边的标签。

6. The domain name (the "right-hand side" of the email address, called the "domain" in [RFC5322]) is appended to the result of step 2 to complete the prepared domain name.

6. 将域名(电子邮件地址的“右侧”,在[RFC5322]中称为“域”)附加到步骤2的结果中,以完成准备好的域名。

For example, to request an OPENPGPKEY resource record for a user whose email address is "hugh@example.com", an OPENPGPKEY query would be placed for the following QNAME: "c93f1e400f26708f98cb19d936620da35 eec8f72e57f9eec01c1afd6._openpgpkey.example.com". The corresponding RR in the example.com zone might look like (key shortened for formatting):

例如,为电子邮件地址为“”的用户请求OPENPGPKEY资源记录hugh@example.com,将为以下QNAME放置OPENPGPKEY查询:“c93f1e400f26708f98cb19d936620da35 eec8f72e57f9eec01cafd6._OPENPGPKEY.example.com”。example.com区域中相应的RR可能如下所示(为格式化而缩短键):

c9[..]d6._openpgpkey.example.com. IN OPENPGPKEY <base64 public key>

c9[…]d6._openpgpkey.example.com。在OPENPGPKEY中<base64公钥>

4. Email Address Variants and Internationalization Considerations
4. 电子邮件地址变体和国际化注意事项

Mail systems usually handle variant forms of local-parts. The most common variants are upper- and lowercase, often automatically corrected when a name is recognized as such. Other variants include systems that ignore "noise" characters such as dots, so that local-parts 'johnsmith' and 'John.Smith' would be equivalent. Many systems allow "extensions" such as 'john-ext' or 'mary+ext' where 'john' or 'mary' is treated as the effective local-part, and 'ext' is passed to the recipient for further handling. This can complicate finding the OPENPGPKEY record associated with the dynamically created email address.

邮件系统通常处理本地部件的各种形式。最常见的变体是大写和小写,通常在识别名称时自动更正。其他变体包括忽略“噪声”字符(如点)的系统,因此本地部分“johnsmith”和“John.Smith”是等效的。许多系统允许“扩展”,如“john ext”或“mary+ext”,其中“john”或“mary”被视为有效的本地部分,“ext”被传递给接收者进行进一步处理。这会使查找与动态创建的电子邮件地址关联的OPENPGPKEY记录变得复杂。

[RFC5321] and its predecessors have always made it clear that only the recipient MTA is allowed to interpret the local-part of an address. Therefore, sending MUAs and MTAs supporting OPENPGPKEY MUST NOT perform any kind of mapping rules based on the email address. In order to improve chances of finding OPENPGP RRs for a particular local-part, domains that allow variant forms (such as treating local-parts as case-insensitive) might publish OPENPGP RRs for all variants of local-parts, might publish variants on first use (for example, a webmail provider that also controls DNS for a domain can publish variants as used by owner of a particular local-part) or just publish OPENPGP RRs for the most common variants.

[RFC5321]及其前身一直明确指出,只有收件人MTA才可以解释地址的本地部分。因此,发送支持OPENPGPKEY的MUA和MTA时,不得基于电子邮件地址执行任何类型的映射规则。为了提高为特定本地部件找到OPENPGP RRs的机会,允许变体形式的域(例如将本地部件视为不区分大小写)可能会为本地部件的所有变体发布OPENPGP RRs,可能会在首次使用时发布变体(例如,还控制域DNS的Web邮件提供商可以发布特定本地部件所有者使用的变体)或仅发布最常见变体的OPENPGP RRs。

Section 3 above defines how the local-part is used to determine the location where one looks for an OPENPGPKEY record. Given the variety of local-parts seen in email, designing a good experiment for this is difficult, as: a) some current implementations are known to lowercase at least US-ASCII local-parts, b) we know from (many) other situations that any strategy based on guessing and making multiple DNS queries is not going to achieve consensus for good reasons, and c) the underlying issues are just hard -- see Section 10.1 of [RFC6530] for discussion of just some of the issues that would need to be tackled to fully address this problem.

上面的第3节定义了如何使用本地部分来确定查找OPENPGPKEY记录的位置。考虑到电子邮件中看到的本地部分的多样性,为此设计一个好的实验是很困难的,因为:a)已知一些当前的实现至少使用小写的US-ASCII本地部分,b)我们从(许多)其他情况中知道,基于猜测和进行多个DNS查询的任何策略都不会出于充分的理由达成共识,和c)根本问题很难解决——请参见[RFC6530]第10.1节,了解为全面解决此问题而需要解决的一些问题的讨论。

However, while this specification is not the place to try to address these issues with local-parts, doing so is also not required to determine the outcome of this experiment. If this experiment succeeds, then further work on email addresses with non-ASCII local-parts will be needed and, based on the findings from this experiment, that would be better than doing nothing or starting this experiment based on a speculative approach to what is a very complex topic.

然而,虽然本规范不是试图解决本地部件的这些问题的地方,但也不需要这样做来确定本实验的结果。如果这项实验成功,那么就需要对带有非ASCII本地部分的电子邮件地址进行进一步的研究,并且根据这项实验的发现,这将比什么都不做或根据一个非常复杂的主题的推测方法开始这项实验要好。

5. Application Use of OPENPGPKEY
5. OPENPGPKEY的应用

The OPENPGPKEY record allows an application or service to obtain an OpenPGP public key and use it for verifying a digital signature or encrypting a message to the public key. The DNS answer MUST pass DNSSEC validation; if DNSSEC validation reaches any state other than "Secure" (as specified in [RFC4035]), the DNSSEC validation MUST be treated as a failure.

OPENPGPKEY记录允许应用程序或服务获取OpenPGP公钥,并将其用于验证数字签名或将消息加密到公钥。DNS应答必须通过DNSSEC验证;如果DNSSEC验证达到除“安全”(如[RFC4035]中规定)以外的任何状态,则必须将DNSSEC验证视为失败。

5.1. Obtaining an OpenPGP Key for a Specific Email Address
5.1. 获取特定电子邮件地址的OpenPGP密钥

If no OpenPGP public keys are known for an email address, an OPENPGPKEY DNS lookup MAY be performed to seek the OpenPGP public key that corresponds to that email address. This public key can then be used to verify a received signed message or can be used to send out an encrypted email message. An application whose attempt fails to retrieve a DNSSEC-verified OPENPGPKEY RR from the DNS should remember that failure for some time to avoid sending out a DNS request for each email message the application is sending out; such DNS requests constitute a privacy leak.

如果电子邮件地址没有已知的OpenPGP公钥,则可以执行OPENPGPKEY DNS查找以查找对应于该电子邮件地址的OpenPGP公钥。然后,该公钥可用于验证收到的签名邮件,或用于发送加密的电子邮件。尝试从DNS检索DNSSEC验证的OPENPGPKEY RR失败的应用程序应记住该失败一段时间,以避免为应用程序发送的每个电子邮件发送DNS请求;此类DNS请求构成隐私泄露。

5.2. Confirming that an OpenPGP Key is Current
5.2. 确认OpenPGP密钥是当前密钥

Locally stored OpenPGP public keys are not automatically refreshed. If the owner of that key creates a new OpenPGP public key, that owner is unable to securely notify all users and applications that have its old OpenPGP public key. Applications and users can perform an OPENPGPKEY lookup to confirm that the locally stored OpenPGP public key is still the correct key to use. If the locally stored OpenPGP public key is different from the DNSSEC-validated OpenPGP public key currently published in DNS, the confirmation MUST be treated as a failure unless the locally stored OpenPGP key signed the newly published OpenPGP public key found in DNS. An application that can interact with the user MAY ask the user for guidance; otherwise, the application will have to apply local policy. For privacy reasons, an application MUST NOT attempt to look up an OpenPGP key from DNSSEC at every use of that key.

本地存储的OpenPGP公钥不会自动刷新。如果该密钥的所有者创建了一个新的OpenPGP公钥,则该所有者无法安全地通知拥有其旧OpenPGP公钥的所有用户和应用程序。应用程序和用户可以执行OPENPGPKEY查找,以确认本地存储的OpenPGP公钥仍然是要使用的正确密钥。如果本地存储的OpenPGP公钥与当前在DNS中发布的经DNSSEC验证的OpenPGP公钥不同,则必须将确认视为失败,除非本地存储的OpenPGP密钥对DNS中新发布的OpenPGP公钥进行签名。可以与用户交互的应用程序可以请求用户提供指导;否则,应用程序将必须应用本地策略。出于隐私原因,应用程序不得在每次使用OpenPGP密钥时尝试从DNSSEC查找该密钥。

5.3. Public Key UIDs and Query Names
5.3. 公钥UID和查询名称

An OpenPGP public key can be associated with multiple email addresses by specifying multiple key UIDs. The OpenPGP public key obtained from an OPENPGPKEY RR can be used as long as the query and resulting data form a proper email to the UID identity association.

通过指定多个密钥UID,OpenPGP公钥可以与多个电子邮件地址相关联。从OPENPGPKEY RR获得的OpenPGP公钥可以使用,只要查询和生成的数据形成到UID标识关联的适当电子邮件。

CNAMEs (see [RFC2181]) and DNAMEs (see [RFC6672]) can be followed to obtain an OPENPGPKEY RR, as long as the original recipient's email address appears as one of the OpenPGP public key UIDs. For example,

只要原始收件人的电子邮件地址显示为OpenPGP公钥UID之一,就可以使用CNAMEs(请参见[RFC2181])和DNAMEs(请参见[RFC6672])来获取OPENPGPKEY RR。例如

if the OPENPGPKEY RR query for hugh@example.com (8d57[...]b7._openpgpkey.example.com) yields a CNAME to 8d57[...]b7._openpgpkey.example.net, and an OPENPGPKEY RR for 8d57[...]b7._openpgpkey.example.net exists, then this OpenPGP public key can be used, provided one of the key UIDs contains "hugh@example.com". This public key cannot be used if it would only contain the key UID "hugh@example.net".

如果OPENPGPKEY RR查询hugh@example.com(8d57[…]b7.\u openpgpkey.example.com)生成8d57[…]b7.\u openpgpkey.example.net的CNAME,以及8d57[…]b7.\u openpgpkey.example.net的openpgpkey RR,如果其中一个密钥UID包含“hugh@example.com". 如果此公钥仅包含密钥UID,则无法使用它”hugh@example.net".

If one of the OpenPGP key UIDs contains only a single wildcard as the left-hand side of the email address, such as "*@example.com", the OpenPGP public key may be used for any email address within that domain. Wildcards at other locations (e.g., "hugh@*.com") or regular expressions in key UIDs are not allowed, and any OPENPGPKEY RR containing these MUST be ignored.

如果其中一个OpenPGP密钥UID仅包含一个通配符作为电子邮件地址的左侧,例如“*@example.com”,则OpenPGP公钥可用于该域内的任何电子邮件地址。不允许在其他位置使用通配符(例如,“hugh@*.com”)或在关键UID中使用正则表达式,并且必须忽略任何包含这些通配符的OPENPGPKEY RR。

6. OpenPGP Key Size and DNS
6. OpenPGP密钥大小和DNS

Due to the expected size of the OPENPGPKEY record, applications SHOULD use TCP -- not UDP -- to perform queries for the OPENPGPKEY resource record.

由于OPENPGPKEY记录的预期大小,应用程序应该使用TCP(而不是UDP)来执行OPENPGPKEY资源记录的查询。

Although the reliability of the transport of large DNS resource records has improved in the last years, it is still recommended to keep the DNS records as small as possible without sacrificing the security properties of the public key. The algorithm type and key size of OpenPGP keys should not be modified to accommodate this section.

尽管大型DNS资源记录传输的可靠性在过去几年中有所提高,但仍建议在不牺牲公钥安全属性的情况下尽可能保持DNS记录的小。OpenPGP密钥的算法类型和密钥大小不应修改以适应此部分。

OpenPGP supports various attributes that do not contribute to the security of a key, such as an embedded image file. It is recommended that these properties not be exported to OpenPGP public keyrings that are used to create OPENPGPKEY resource records. Some OpenPGP software (for example, GnuPG) supports a "minimal key export" that is well suited to use as OPENPGPKEY RDATA. See Appendix A.

OpenPGP支持不影响密钥安全性的各种属性,例如嵌入式图像文件。建议不要将这些属性导出到用于创建OPENPGPKEY资源记录的OpenPGP公钥环。一些OpenPGP软件(例如GnuPG)支持“最小密钥导出”,非常适合用作OPENPGPKEY RDATA。见附录A。

7. Security Considerations
7. 安全考虑

DNSSEC is not an alternative for the "web of trust" or for manual fingerprint verification by users. DANE for OpenPGP, as specified in this document, is a solution aimed to ease obtaining someone's public key. Without manual verification of the OpenPGP key obtained via DANE, this retrieved key should only be used for encryption if the only other alternative is sending the message in plaintext. While this thwarts all passive attacks that simply capture and log all plaintext email content, it is not a security measure against active attacks. A user who publishes an OPENPGPKEY record in DNS still

DNSSEC不是“信任网”或用户手动指纹验证的替代方案。如本文所述,DANE for OpenPGP是一种旨在简化获取某人公钥的解决方案。在没有手动验证通过DANE获得的OpenPGP密钥的情况下,如果唯一的替代方案是以明文发送消息,则仅应将检索到的密钥用于加密。虽然这可以阻止所有被动攻击,而这些攻击只是捕获并记录所有明文电子邮件内容,但它并不是针对主动攻击的安全措施。在DNS中发布OPENPGPKEY记录的用户

expects senders to perform their due diligence by additional (non-DNSSEC) verification of their public key via other out-of-band methods before sending any confidential or sensitive information.

期望发件人在发送任何机密或敏感信息之前,通过其他带外方法对其公钥进行额外(非DNSSEC)验证,以履行其尽职调查。

In other words, the OPENPGPKEY record MUST NOT be used to send sensitive information without additional verification or confirmation that the OpenPGP key actually belongs to the target recipient.

换句话说,在未进一步验证或确认OpenPGP密钥实际上属于目标收件人之前,不得使用OPENPGPKEY记录发送敏感信息。

DNSSEC does not protect the queries from Pervasive Monitoring as defined in [RFC7258]. Since DNS queries are currently mostly unencrypted, a query to look up a target OPENPGPKEY record could reveal that a user using the (monitored) recursive DNS server is attempting to send encrypted email to a target. This information is normally protected by the MUAs and MTAs by using Transport Layer Security (TLS) encryption using STARTTLS. The DNS itself can mitigate some privacy concerns, but the user needs to select a trusted DNS server that supports these privacy-enhancing features. Recursive DNS servers can support DNS Query Name Minimalisation [RFC7816], which limits leaking the QNAME to only the recursive DNS server and the nameservers of the actual zone being queried for. Recursive DNS servers can also support TLS [RFC7858] to ensure that the path between the end user and the recursive DNS server is encrypted.

DNSSEC不保护查询免受[RFC7258]中定义的普遍监控。由于DNS查询目前大多未加密,因此查询目标OPENPGPKEY记录可能会发现使用(受监控的)递归DNS服务器的用户正试图向目标发送加密电子邮件。此信息通常由MUA和MTA通过使用STARTTLS的传输层安全(TLS)加密进行保护。DNS本身可以缓解一些隐私问题,但用户需要选择支持这些隐私增强功能的受信任DNS服务器。递归DNS服务器可以支持DNS查询名称最小化[RFC7816],这将限制QNAME仅泄漏给递归DNS服务器和所查询实际区域的名称服务器。递归DNS服务器还可以支持TLS[RFC7858],以确保最终用户和递归DNS服务器之间的路径是加密的。

Various components could be responsible for encrypting an email message to a target recipient. It could be done by the sender's MUA or a MUA plug-in or the sender's MTA. Each of these have their own characteristics. A MUA can ask the user to make a decision before continuing. The MUA can either accept or refuse a message. The MTA must deliver the message as-is, or encrypt the message before delivering. Each of these components should attempt to encrypt an unencrypted outgoing message whenever possible.

各种组件可能负责加密发送给目标收件人的电子邮件。它可以由发送方的MUA或MUA插件或发送方的MTA完成。每一种都有自己的特点。MUA可以要求用户在继续之前做出决定。MUA可以接受或拒绝消息。MTA必须按原样传递邮件,或在传递前对邮件进行加密。只要可能,这些组件中的每一个都应该尝试加密未加密的传出消息。

In theory, two different local-parts could hash to the same value. This document assumes that such a hash collision has a negligible chance of happening.

理论上,两个不同的局部部分可以散列为相同的值。本文档假设这种哈希冲突发生的可能性很小。

Organizations that are required to be able to read everyone's encrypted email should publish the escrow key as the OPENPGPKEY record. Mail servers of such organizations MAY optionally re-encrypt the message to the individual's OpenPGP key.

需要能够读取每个人的加密电子邮件的组织应将托管密钥发布为OPENPGPKEY记录。此类组织的邮件服务器可以选择将邮件重新加密到个人的OpenPGP密钥。

7.1. MTA Behavior
7.1. MTA行为

An MTA could be operating in a stand-alone mode, without access to the sender's OpenPGP public keyring, or in a way where it can access the user's OpenPGP public keyring. Regardless, the MTA MUST NOT modify the user's OpenPGP keyring.

MTA可以在独立模式下运行,无需访问发件人的OpenPGP公钥环,也可以访问用户的OpenPGP公钥环。无论如何,MTA不得修改用户的OpenPGP密钥环。

An MTA sending an email MUST NOT add the public key obtained from an OPENPGPKEY resource record to a permanent public keyring for future use beyond the TTL.

发送电子邮件的MTA不得将从OPENPGPKEY资源记录中获取的公钥添加到永久公钥环中,以备将来在TTL之外使用。

If the obtained public key is revoked, the MTA MUST NOT use the key for encryption, even if that would result in sending the message in plaintext.

如果获取的公钥被吊销,MTA不得使用该密钥进行加密,即使这会导致以明文形式发送邮件。

If a message is already encrypted, the MTA SHOULD NOT re-encrypt the message, even if different encryption schemes or different encryption keys would be used.

如果邮件已加密,MTA不应重新加密邮件,即使使用不同的加密方案或加密密钥。

If the DNS request for an OPENPGPKEY record returned an Indeterminate or Bogus answer as specified in [RFC4035], the MTA MUST NOT send the message and queue the plaintext message for encrypted delivery at a later time. If the problem persists, the email should be returned via the regular bounce methods.

如果针对OPENPGPKEY记录的DNS请求返回了[RFC4035]中指定的不确定或虚假答案,MTA不得发送该消息并将明文消息排队,以便稍后进行加密传递。如果问题仍然存在,则应通过常规跳出方法返回电子邮件。

If multiple non-revoked OPENPGPKEY resource records are found, the MTA SHOULD pick the most secure RR based on its local policy.

如果找到多个未吊销的OPENPGPKEY资源记录,MTA应根据其本地策略选择最安全的RR。

7.2. MUA Behavior
7.2. MUA行为

If the public key for a recipient obtained from the locally stored sender's public keyring differs from the recipient's OPENPGPKEY RR, the MUA SHOULD halt processing the message and interact with the user to resolve the conflict before continuing to process the message.

如果从本地存储的发送方公钥环获取的接收方公钥与接收方的OPENPGPKEY RR不同,则MUA应停止处理该消息,并在继续处理该消息之前与用户交互以解决冲突。

If the public key for a recipient obtained from the locally stored sender's public keyring contains contradicting properties for the same key obtained from an OPENPGPKEY RR, the MUA SHOULD NOT accept the message for delivery.

如果从本地存储的发送方公钥环获取的接收方公钥包含从OPENPGPKEY RR获取的同一密钥的矛盾属性,则MUA不应接受该消息进行传递。

If multiple non-revoked OPENPGPKEY resource records are found, the MUA SHOULD pick the most secure OpenPGP public key based on its local policy.

如果发现多个未撤销的OPENPGPKEY资源记录,MUA应根据其本地策略选择最安全的OpenPGP公钥。

The MUA MAY interact with the user to resolve any conflicts between locally stored keyrings and OPENPGPKEY RRdata.

MUA可以与用户交互以解决本地存储的密钥环和OPENPGPKEY RRdata之间的任何冲突。

A MUA that is encrypting a message SHOULD clearly indicate to the user the difference between encrypting to a locally stored and previously user-verified public key and encrypting to a public key obtained via an OPENPGPKEY resource record that was not manually verified by the user in the past.

加密消息的MUA应向用户明确指出加密到本地存储和以前用户验证的公钥与加密到通过OPENPGPKEY资源记录获得的公钥之间的区别,该记录在过去未经用户手动验证。

7.3. Response Size
7.3. 响应大小

To prevent amplification attacks, an Authoritative DNS server MAY wish to prevent returning OPENPGPKEY records over UDP unless the source IP address has been confirmed with [RFC7873]. Such servers MUST NOT return REFUSED, but answer the query with an empty answer section and the truncation flag set ("TC=1").

为了防止放大攻击,权威DNS服务器可能希望阻止通过UDP返回OPENPGPKEY记录,除非源IP地址已通过[RFC7873]确认。此类服务器不能返回拒绝,而是使用空的应答部分和截断标志集(“TC=1”)应答查询。

7.4. Email Address Information Leak
7.4. 电子邮件地址信息泄漏

The hashing of the local-part in this document is not a security feature. Publishing OPENPGPKEY records will create a list of hashes of valid email addresses, which could simplify obtaining a list of valid email addresses for a particular domain. It is desirable to not ease the harvesting of email addresses where possible.

本文档中本地部分的哈希不是安全特性。发布OPENPGPKEY记录将创建有效电子邮件地址的哈希列表,这可以简化获取特定域的有效电子邮件地址列表的过程。在可能的情况下,最好不要轻易获取电子邮件地址。

The domain name part of the email address is not used as part of the hash so that hashes can be used in multiple zones deployed using DNAME [RFC6672]. This does makes it slightly easier and cheaper to brute-force the SHA2-256 hashes into common and short local-parts, as single rainbow tables can be re-used across domains. This can be somewhat countered by using NextSECure version 3 (NSEC3).

电子邮件地址的域名部分不用作哈希的一部分,因此可以在使用DNAME[RFC6672]部署的多个区域中使用哈希。这使得将SHA2-256哈希强制转换为公共和简短的本地部分变得更加简单和便宜,因为单个彩虹表可以跨域重复使用。使用NextSECure版本3(NSEC3)可以在一定程度上解决这一问题。

DNS zones that are signed with DNSSEC using NSEC for denial of existence are susceptible to zone walking, a mechanism that allows someone to enumerate all the OPENPGPKEY hashes in a zone. This can be used in combination with previously hashed common or short local-parts (in rainbow tables) to deduce valid email addresses. DNSSEC-signed zones using NSEC3 for denial of existence instead of NSEC are significantly harder to brute-force after performing a zone walk.

使用NSEC为拒绝存在而与DNSSEC签名的DNS区域易受区域漫游的影响,该机制允许某人枚举区域中的所有OPENPGPKEY哈希。这可以与之前散列的公共或短本地部分(在rainbow表中)结合使用,以推断有效的电子邮件地址。在执行区域漫游后,使用NSEC3而不是NSEC进行拒绝存在的DNSSEC签名区域更难进行暴力攻击。

7.5. Storage of OPENPGPKEY Data
7.5. OPENPGPKEY数据的存储

Users may have a local key store with OpenPGP public keys. An application supporting the use of OPENPGPKEY DNS records MUST NOT modify the local key store without explicit confirmation of the user, as the application is unaware of the user's personal policy for adding, removing, or updating their local key store. An application MAY warn the user if an OPENPGPKEY record does not match the OpenPGP public key in the local key store.

用户可能有一个带有OpenPGP公钥的本地密钥存储。未经用户明确确认,支持使用OPENPGPKEY DNS记录的应用程序不得修改本地密钥存储,因为应用程序不知道用户添加、删除或更新其本地密钥存储的个人策略。如果OPENPGPKEY记录与本地密钥存储中的OpenPGP公钥不匹配,应用程序可能会警告用户。

Applications that cannot interact with users, such as daemon processes, SHOULD store OpenPGP public keys obtained via OPENPGPKEY up to their DNS TTL value. This avoids repeated DNS lookups that third parties could monitor to determine when an email is being sent to a particular user.

无法与用户交互的应用程序(如守护进程)应将通过OPENPGPKEY获得的OpenPGP公钥存储到其DNS TTL值。这避免了第三方可以监视的重复DNS查找,以确定电子邮件何时发送给特定用户。

7.6. Security of OpenPGP versus DNSSEC
7.6. OpenPGP与DNSSEC的安全性

Anyone who can obtain a DNSSEC private key of a domain name via coercion, theft, or brute-force calculations, can replace any OPENPGPKEY record in that zone and all of the delegated child zones. Any future messages encrypted with the malicious OpenPGP key could then be read.

任何可以通过强制、盗窃或暴力计算获得域名DNSSEC私钥的人都可以替换该区域和所有委托子区域中的任何OPENPGPKEY记录。任何使用恶意OpenPGP密钥加密的未来消息都可能被读取。

Therefore, an OpenPGP key obtained via a DNSSEC-validated OPENPGPKEY record can only be trusted as much as the DNS domain can be trusted, and is no substitute for in-person OpenPGP key verification or additional OpenPGP verification via "web of trust" signatures present on the OpenPGP in question.

因此,通过DNSSEC验证的OPENPGPKEY记录获得的OpenPGP密钥只能在DNS域可信任的范围内被信任,并且不能替代当面OpenPGP密钥验证或通过相关OpenPGP上存在的“信任网”签名进行的额外OpenPGP验证。

8. IANA Considerations
8. IANA考虑
8.1. OPENPGPKEY RRtype
8.1. OPENPGPKEY RRtype

This document uses a new DNS RR type, OPENPGPKEY, whose value 61 has been allocated by IANA from the "Resource Record (RR) TYPEs" subregistry of the "Domain Name System (DNS) Parameters" registry.

本文档使用新的DNS RR类型OPENPGPKEY,其值61已由IANA从“域名系统(DNS)参数”注册表的“资源记录(RR)类型”子区分配。

The IANA template for OPENPGPKEY is listed in Appendix B. It was submitted to IANA for review on July 23, 2014 and approved on August 12, 2014.

附录B中列出了OPENPGPKEY的IANA模板。该模板于2014年7月23日提交给IANA审查,并于2014年8月12日获得批准。

9. References
9. 工具书类
9.1. Normative References
9.1. 规范性引用文件

[RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, November 1987, <http://www.rfc-editor.org/info/rfc1035>.

[RFC1035]Mockapetris,P.,“域名-实现和规范”,STD 13,RFC 1035,DOI 10.17487/RFC1035,1987年11月<http://www.rfc-editor.org/info/rfc1035>.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://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<http://www.rfc-editor.org/info/rfc2119>.

[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, <http://www.rfc-editor.org/info/rfc2181>.

[RFC2181]Elz,R.和R.Bush,“DNS规范的澄清”,RFC 2181,DOI 10.17487/RFC2181,1997年7月<http://www.rfc-editor.org/info/rfc2181>.

[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, DOI 10.17487/RFC4033, March 2005, <http://www.rfc-editor.org/info/rfc4033>.

[RFC4033]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全介绍和要求”,RFC 4033,DOI 10.17487/RFC4033,2005年3月<http://www.rfc-editor.org/info/rfc4033>.

[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, DOI 10.17487/RFC4034, March 2005, <http://www.rfc-editor.org/info/rfc4034>.

[RFC4034]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全扩展的资源记录”,RFC 4034,DOI 10.17487/RFC4034,2005年3月<http://www.rfc-editor.org/info/rfc4034>.

[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, <http://www.rfc-editor.org/info/rfc4035>.

[RFC4035]Arends,R.,Austein,R.,Larson,M.,Massey,D.,和S.Rose,“DNS安全扩展的协议修改”,RFC 4035,DOI 10.17487/RFC4035,2005年3月<http://www.rfc-editor.org/info/rfc4035>.

[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, <http://www.rfc-editor.org/info/rfc4648>.

[RFC4648]Josefsson,S.,“Base16、Base32和Base64数据编码”,RFC 4648,DOI 10.17487/RFC4648,2006年10月<http://www.rfc-editor.org/info/rfc4648>.

[RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. Thayer, "OpenPGP Message Format", RFC 4880, DOI 10.17487/RFC4880, November 2007, <http://www.rfc-editor.org/info/rfc4880>.

[RFC4880]Callas,J.,Donnerhacke,L.,Finney,H.,Shaw,D.,和R.Thayer,“OpenPGP消息格式”,RFC 4880,DOI 10.17487/RFC4880,2007年11月<http://www.rfc-editor.org/info/rfc4880>.

[RFC5754] Turner, S., "Using SHA2 Algorithms with Cryptographic Message Syntax", RFC 5754, DOI 10.17487/RFC5754, January 2010, <http://www.rfc-editor.org/info/rfc5754>.

[RFC5754]Turner,S.,“使用具有加密消息语法的SHA2算法”,RFC 5754,DOI 10.17487/RFC5754,2010年1月<http://www.rfc-editor.org/info/rfc5754>.

9.2. Informative References
9.2. 资料性引用

[HKP] Shaw, D., "The OpenPGP HTTP Keyserver Protocol (HKP)", Work in Progress, draft-shaw-openpgp-hkp-00, March 2003.

[HKP]Shaw,D.,“OpenPGP HTTP密钥服务器协议(HKP)”,正在进行的工作,草稿-Shaw-OpenPGP-HKP-00,2003年3月。

[MAILBOX] Levine, J., "Encoding mailbox local-parts in the DNS", Work in Progress, draft-levine-dns-mailbox-01, September 2015.

[邮箱]Levine,J.,“在DNS中编码邮箱本地部分”,正在进行的工作,草稿-Levine-DNS-MAILBOX-012015年9月。

[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record (RR) Types", RFC 3597, DOI 10.17487/RFC3597, September 2003, <http://www.rfc-editor.org/info/rfc3597>.

[RFC3597]Gustafsson,A.,“未知DNS资源记录(RR)类型的处理”,RFC 3597,DOI 10.17487/RFC3597,2003年9月<http://www.rfc-editor.org/info/rfc3597>.

[RFC4255] Schlyter, J. and W. Griffin, "Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints", RFC 4255, DOI 10.17487/RFC4255, January 2006, <http://www.rfc-editor.org/info/rfc4255>.

[RFC4255]Schlyter,J.和W.Griffin,“使用DNS安全发布安全外壳(SSH)密钥指纹”,RFC 4255,DOI 10.17487/RFC4255,2006年1月<http://www.rfc-editor.org/info/rfc4255>.

[RFC4398] Josefsson, S., "Storing Certificates in the Domain Name System (DNS)", RFC 4398, DOI 10.17487/RFC4398, March 2006, <http://www.rfc-editor.org/info/rfc4398>.

[RFC4398]Josefsson,S.,“在域名系统(DNS)中存储证书”,RFC 4398,DOI 10.17487/RFC4398,2006年3月<http://www.rfc-editor.org/info/rfc4398>.

[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, DOI 10.17487/RFC5321, October 2008, <http://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<http://www.rfc-editor.org/info/rfc5321>.

[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, DOI 10.17487/RFC5322, October 2008, <http://www.rfc-editor.org/info/rfc5322>.

[RFC5322]Resnick,P.,Ed.,“互联网信息格式”,RFC 5322,DOI 10.17487/RFC5322,2008年10月<http://www.rfc-editor.org/info/rfc5322>.

[RFC6530] Klensin, J. and Y. Ko, "Overview and Framework for Internationalized Email", RFC 6530, DOI 10.17487/RFC6530, February 2012, <http://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<http://www.rfc-editor.org/info/rfc6530>.

[RFC6672] Rose, S. and W. Wijngaards, "DNAME Redirection in the DNS", RFC 6672, DOI 10.17487/RFC6672, June 2012, <http://www.rfc-editor.org/info/rfc6672>.

[RFC6672]Rose,S.和W.Wijngaards,“DNS中的DNAME重定向”,RFC 6672,DOI 10.17487/RFC6672,2012年6月<http://www.rfc-editor.org/info/rfc6672>.

[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August 2012, <http://www.rfc-editor.org/info/rfc6698>.

[RFC6698]Hoffman,P.和J.Schlyter,“基于DNS的命名实体认证(DANE)传输层安全(TLS)协议:TLSA”,RFC 6698,DOI 10.17487/RFC6698,2012年8月<http://www.rfc-editor.org/info/rfc6698>.

[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May 2014, <http://www.rfc-editor.org/info/rfc7258>.

[RFC7258]Farrell,S.和H.Tschofenig,“普遍监控是一种攻击”,BCP 188,RFC 7258,DOI 10.17487/RFC7258,2014年5月<http://www.rfc-editor.org/info/rfc7258>.

[RFC7816] Bortzmeyer, S., "DNS Query Name Minimisation to Improve Privacy", RFC 7816, DOI 10.17487/RFC7816, March 2016, <http://www.rfc-editor.org/info/rfc7816>.

[RFC7816]Bortzmeyer,S.,“DNS查询名称最小化以改善隐私”,RFC 7816,DOI 10.17487/RFC7816,2016年3月<http://www.rfc-editor.org/info/rfc7816>.

[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., and P. Hoffman, "Specification for DNS over Transport Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 2016, <http://www.rfc-editor.org/info/rfc7858>.

[RFC7858]Hu,Z.,Zhu,L.,Heidemann,J.,Mankin,A.,Wessels,D.,和P.Hoffman,“DNS传输层安全规范(TLS)”,RFC 7858,DOI 10.17487/RFC7858,2016年5月<http://www.rfc-editor.org/info/rfc7858>.

[RFC7873] Eastlake 3rd, D. and M. Andrews, "Domain Name System (DNS) Cookies", RFC 7873, DOI 10.17487/RFC7873, May 2016, <http://www.rfc-editor.org/info/rfc7873>.

[RFC7873]Eastlake 3rd,D.和M.Andrews,“域名系统(DNS)Cookies”,RFC 7873,DOI 10.17487/RFC7873,2016年5月<http://www.rfc-editor.org/info/rfc7873>.

[SMIME] Hoffman, P. and J. Schlyter, "Using Secure DNS to Associate Certificates with Domain Names For S/MIME", Work in Progress, draft-ietf-dane-smime-12, July 2016.

[SMIME]Hoffman,P.和J.Schlyter,“使用安全DNS将证书与S/MIME域名关联”,正在进行的工作,草稿-ietf-dane-SMIME-12,2016年7月。

[Unicode90] The Unicode Consortium, "The Unicode Standard, Version 9.0.0", (Mountain View, CA: The Unicode Consortium, 2016. ISBN 978-1-936213-13-9), <http://www.unicode.org/versions/Unicode9.0.0/>.

[Unicode 90]Unicode联盟,“Unicode标准,9.0.0版”(加利福尼亚州山景城:Unicode联盟,2016年,ISBN 978-1-936213-13-9)<http://www.unicode.org/versions/Unicode9.0.0/>.

Appendix A. Generating OPENPGPKEY Records
附录A.生成OPENPGPKEY记录

The commonly available GnuPG software can be used to generate a minimum Transferable Public Key for the RRdata portion of an OPENPGPKEY record:

常用的GnuPG软件可用于为OPENPGPKEY记录的RRdata部分生成最小可转移公钥:

gpg --export --export-options export-minimal,no-export-attributes \ hugh@example.com | base64

gpg--导出--导出选项导出最小值,无导出属性\hugh@example.com| base64

The --armor or -a option of the gpg command should not be used, as it adds additional markers around the armored key.

不应使用gpg命令的--armor或-a选项,因为它会在铠装键周围添加额外的标记。

When DNS software reading or signing of the zone file does not yet support the OPENPGPKEY RRtype, the Generic Record Syntax of [RFC3597] can be used to generate the RDATA. One needs to calculate the number of octets and the actual data in hexadecimal:

当区域文件的DNS软件读取或签名尚不支持OPENPGPKEY RRtype时,可使用[RFC3597]的通用记录语法生成RDATA。需要计算八位字节数和十六进制的实际数据:

   gpg --export --export-options export-minimal,no-export-attributes \
       hugh@example.com | wc -c
   gpg --export --export-options export-minimal,no-export-attributes \
       hugh@example.com | hexdump -e \
          '"\t" /1 "%.2x"' -e '/32 "\n"'
        
   gpg --export --export-options export-minimal,no-export-attributes \
       hugh@example.com | wc -c
   gpg --export --export-options export-minimal,no-export-attributes \
       hugh@example.com | hexdump -e \
          '"\t" /1 "%.2x"' -e '/32 "\n"'
        

These values can then be used to generate a generic record (line break has been added for formatting):

然后可以使用这些值生成一般记录(已添加换行符以进行格式化):

   <SHA2-256-trunc(hugh)>._openpgpkey.example.com. IN TYPE61 \# \
       <numOctets> <keydata in hex>
        
   <SHA2-256-trunc(hugh)>._openpgpkey.example.com. IN TYPE61 \# \
       <numOctets> <keydata in hex>
        

The openpgpkey command in the hash-slinger software can be used to generate complete OPENPGPKEY records

hash-slinger软件中的openpgpkey命令可用于生成完整的openpgpkey记录

   ~> openpgpkey --output rfc hugh@example.com
   c9[..]d6._openpgpkey.example.com. IN OPENPGPKEY mQCNAzIG[...]
        
   ~> openpgpkey --output rfc hugh@example.com
   c9[..]d6._openpgpkey.example.com. IN OPENPGPKEY mQCNAzIG[...]
        
   ~> openpgpkey --output generic hugh@example.com
   c9[..]d6._openpgpkey.example.com. IN TYPE61 \# 2313 99008d03[...]
        
   ~> openpgpkey --output generic hugh@example.com
   c9[..]d6._openpgpkey.example.com. IN TYPE61 \# 2313 99008d03[...]
        
Appendix B. OPENPGPKEY IANA Template
附录B.OPENPGPKEY IANA模板

This is a copy of the original registration template submitted to IANA; the text (including the references) has not been updated.

这是提交给IANA的原始注册模板的副本;文本(包括参考文献)尚未更新。

A. Submission Date: 23-07-2014

A.提交日期:2014年7月23日

B.1 Submission Type: [x] New RRTYPE [ ] Modification to RRTYPE B.2 Kind of RR: [x] Data RR [ ] Meta-RR

B.1提交类型:[x]新RRTYPE[]对RRTYPE B的修改。2 RR类型:[x]数据RR[]元RR

  C. Contact Information for submitter (will be publicly posted):
     Name: Paul Wouters         Email Address: pwouters@redhat.com
     International telephone number: +1-647-896-3464
     Other contact handles: paul@nohats.ca
        
  C. Contact Information for submitter (will be publicly posted):
     Name: Paul Wouters         Email Address: pwouters@redhat.com
     International telephone number: +1-647-896-3464
     Other contact handles: paul@nohats.ca
        

D. Motivation for the new RRTYPE application.

D.新RRTYPE应用的动机。

Publishing RFC-4880 OpenPGP formatted keys in DNS with DNSSEC protection to faciliate automatic encryption of emails in defense against pervasive monitoring.

在具有DNSSEC保护的DNS中发布RFC-4880 OpenPGP格式的密钥,以方便电子邮件的自动加密,从而抵御无处不在的监视。

E. Description of the proposed RR type.

E.建议RR类型的说明。

  http://tools.ietf.org/html/draft-ietf-dane-openpgpkey-00#section-2
        
  http://tools.ietf.org/html/draft-ietf-dane-openpgpkey-00#section-2
        

F. What existing RRTYPE or RRTYPEs come closest to filling that need and why are they unsatisfactory?

F.哪些现有的RRTYPE或RRTYPE最接近满足该需求,为什么它们不令人满意?

The CERT RRtype is the closest match. It unfortunately depends on subtyping, and its use in general is no longer recommended. It also has no human usable presentation format. Some usage types of CERT require external URI's which complicates the security model. This was discussed in the dane working group.

证书RRtype是最接近的匹配项。不幸的是,它依赖于子类型,一般不再推荐使用它。它也没有人类可用的表示格式。证书的某些使用类型需要外部URI,这使安全模型复杂化。丹麦工作组对此进行了讨论。

G. What mnemonic is requested for the new RRTYPE (optional)?

G.新RRTYPE需要什么助记符(可选)?

OPENPGPKEY

OPENPGPKEY

H. Does the requested RRTYPE make use of any existing IANA registry or require the creation of a new IANA subregistry in DNS Parameters? If so, please indicate which registry is to be used or created. If a new subregistry is needed, specify the allocation policy for it and its initial contents. Also include what the modification procedures will be.

H.请求的RRTYPE是否使用任何现有的IANA注册表或要求在DNS参数中创建新的IANA子域?如果是,请说明将使用或创建哪个注册表。如果需要新的子省,请指定其分配策略及其初始内容。还包括修改程序。

     The RDATA part uses the key format specified in RFC-4880, which
     itself use
     https://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtm
        
     The RDATA part uses the key format specified in RFC-4880, which
     itself use
     https://www.iana.org/assignments/pgp-parameters/pgp-parameters.xhtm
        

This RRcode just uses the formats specified in those registries for its RRdata part.

此RRcode仅使用这些注册表中为其RRdata部分指定的格式。

I. Does the proposal require/expect any changes in DNS servers/resolvers that prevent the new type from being processed as an unknown RRTYPE (see [RFC3597])?

I.提案是否要求/预期DNS服务器/解析程序中的任何更改,以防止将新类型作为未知RRTYPE处理(请参见[RFC3597])?

No.

J. Comments:

J.评论:

Currently, three software implementations of draft-ietf-dane-openpgpkey are using a private number.

目前,ietf草案dane openpgpkey的三个软件实现都使用一个专用号码。

Acknowledgments

致谢

This document is based on [RFC4255] and [SMIME] whose authors are Paul Hoffman, Jakob Schlyter, and W. Griffin. Olafur Gudmundsson provided feedback and suggested various improvements. Willem Toorop contributed the gpg and hexdump command options. Daniel Kahn Gillmor provided the text describing the OpenPGP packet formats and filtering options. Edwin Taylor contributed language improvements for various iterations of this document. Text regarding email mappings was taken from [MAILBOX] whose author is John Levine.

本文档基于[RFC4255]和[SMIME],其作者是Paul Hoffman、Jakob Schlyter和W.Griffin。Olafur Gudmundsson提供了反馈并提出了各种改进建议。Willem Toorop提供了gpg和hexdump命令选项。Daniel Kahn Gillmor提供了描述OpenPGP数据包格式和过滤选项的文本。Edwin Taylor为本文档的各种迭代提供了语言改进。有关电子邮件映射的文本取自[MAILBOX],其作者是John Levine。

Author's Address

作者地址

Paul Wouters Red Hat

保罗·沃特斯红帽

   Email: pwouters@redhat.com
        
   Email: pwouters@redhat.com