draft-ietf-dnsext-rfc2538bis-08.txt   draft-ietf-dnsext-rfc2538bis-09.txt 
Network Working Group S. Josefsson Network Working Group S. Josefsson
Obsoletes: 2538 (if approved) Obsoletes: 2538 (if approved)
Expires: April 2, 2006 Expires: April 21, 2006
Storing Certificates in the Domain Name System (DNS) Storing Certificates in the Domain Name System (DNS)
draft-ietf-dnsext-rfc2538bis-08 draft-ietf-dnsext-rfc2538bis-09
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
Cryptographic public keys are frequently published and their Cryptographic public keys are frequently published and their
authenticity demonstrated by certificates. A CERT resource record authenticity demonstrated by certificates. A CERT resource record
(RR) is defined so that such certificates and related certificate (RR) is defined so that such certificates and related certificate
skipping to change at page 2, line 17 skipping to change at page 2, line 17
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The CERT Resource Record . . . . . . . . . . . . . . . . . . . 3 2. The CERT Resource Record . . . . . . . . . . . . . . . . . . . 3
2.1. Certificate Type Values . . . . . . . . . . . . . . . . . 4 2.1. Certificate Type Values . . . . . . . . . . . . . . . . . 4
2.2. Text Representation of CERT RRs . . . . . . . . . . . . . 5 2.2. Text Representation of CERT RRs . . . . . . . . . . . . . 5
2.3. X.509 OIDs . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3. X.509 OIDs . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Appropriate Owner Names for CERT RRs . . . . . . . . . . . . . 6 3. Appropriate Owner Names for CERT RRs . . . . . . . . . . . . . 6
3.1. Content-based X.509 CERT RR Names . . . . . . . . . . . . 7 3.1. Content-based X.509 CERT RR Names . . . . . . . . . . . . 7
3.2. Purpose-based X.509 CERT RR Names . . . . . . . . . . . . 8 3.2. Purpose-based X.509 CERT RR Names . . . . . . . . . . . . 8
3.3. Content-based OpenPGP CERT RR Names . . . . . . . . . . . 9 3.3. Content-based OpenPGP CERT RR Names . . . . . . . . . . . 9
3.4. Purpose-based OpenPGP CERT RR Names . . . . . . . . . . . 9 3.4. Purpose-based OpenPGP CERT RR Names . . . . . . . . . . . 9
3.5. Owner names for IPKIX, ISPKI, and IPGP . . . . . . . . . . 10 3.5. Owner names for IPKIX, ISPKI, IPGP, and IACPKIX . . . . . 10
4. Performance Considerations . . . . . . . . . . . . . . . . . . 10 4. Performance Considerations . . . . . . . . . . . . . . . . . . 10
5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 10 5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9. Changes since RFC 2538 . . . . . . . . . . . . . . . . . . . . 12 9. Changes since RFC 2538 . . . . . . . . . . . . . . . . . . . . 12
Appendix A. Copying conditions . . . . . . . . . . . . . . . . . 13 Appendix A. Copying conditions . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . . 14 10.2. Informative References . . . . . . . . . . . . . . . . . . 14
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
Intellectual Property and Copyright Statements . . . . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . . . . 17
1. Introduction 1. Introduction
Public keys are frequently published in the form of a certificate and Public keys are frequently published in the form of a certificate and
their authenticity is commonly demonstrated by certificates and their authenticity is commonly demonstrated by certificates and
related certificate revocation lists (CRLs). A certificate is a related certificate revocation lists (CRLs). A certificate is a
binding, through a cryptographic digital signature, of a public key, binding, through a cryptographic digital signature, of a public key,
a validity interval and/or conditions, and identity, authorization, a validity interval and/or conditions, and identity, authorization,
or other information. A certificate revocation list is a list of or other information. A certificate revocation list is a list of
certificates that are revoked, and incidental information, all signed certificates that are revoked, and incidental information, all signed
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certificates/revocations used by OpenPGP software. certificates/revocations used by OpenPGP software.
Section 2 below specifies a CERT resource record (RR) for the storage Section 2 below specifies a CERT resource record (RR) for the storage
of certificates in the Domain Name System [1] [2]. of certificates in the Domain Name System [1] [2].
Section 3 discusses appropriate owner names for CERT RRs. Section 3 discusses appropriate owner names for CERT RRs.
Sections 4, 5, and 6 below cover performance, IANA, and security Sections 4, 5, and 6 below cover performance, IANA, and security
considerations, respectively. considerations, respectively.
Section 9 explain the changes in this document compared to RFC 2538.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [3]. document are to be interpreted as described in [3].
2. The CERT Resource Record 2. The CERT Resource Record
The CERT resource record (RR) has the structure given below. Its RR The CERT resource record (RR) has the structure given below. Its RR
type code is 37. type code is 37.
1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
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| algorithm | / | algorithm | /
+---------------+ certificate or CRL / +---------------+ certificate or CRL /
/ / / /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
The type field is the certificate type as defined in section 2.1 The type field is the certificate type as defined in section 2.1
below. below.
The key tag field is the 16 bit value computed for the key embedded The key tag field is the 16 bit value computed for the key embedded
in the certificate, using the RRSIG Key Tag algorithm described in in the certificate, using the RRSIG Key Tag algorithm described in
Appendix B of [11]. This field is used as an efficiency measure to Appendix B of [12]. This field is used as an efficiency measure to
pick which CERT RRs may be applicable to a particular key. The key pick which CERT RRs may be applicable to a particular key. The key
tag can be calculated for the key in question and then only CERT RRs tag can be calculated for the key in question and then only CERT RRs
with the same key tag need be examined. Note that two different keys with the same key tag need be examined. Note that two different keys
may have the same key tag. However, the key must always be can have the same key tag. However, the key MUST be transformed to
transformed to the format it would have as the public key portion of the format it would have as the public key portion of a DNSKEY RR
a DNSKEY RR before the key tag is computed. This is only possible if before the key tag is computed. This is only possible if the key is
the key is applicable to an algorithm and complies to limits (such as applicable to an algorithm and complies to limits (such as key size)
key size) defined for DNS security. If it is not, the algorithm defined for DNS security. If it is not, the algorithm field MUST be
field MUST be zero and the tag field is meaningless and SHOULD be zero and the tag field is meaningless and SHOULD be zero.
zero.
The algorithm field has the same meaning as the algorithm field in The algorithm field has the same meaning as the algorithm field in
DNSKEY and RRSIG RRs [11], except that a zero algorithm field DNSKEY and RRSIG RRs [12], except that a zero algorithm field
indicates the algorithm is unknown to a secure DNS, which may simply indicates the algorithm is unknown to a secure DNS, which may simply
be the result of the algorithm not having been standardized for be the result of the algorithm not having been standardized for
DNSSEC [10]. DNSSEC [11].
2.1. Certificate Type Values 2.1. Certificate Type Values
The following values are defined or reserved: The following values are defined or reserved:
Value Mnemonic Certificate Type Value Mnemonic Certificate Type
----- -------- ---------------- ----- -------- ----------------
0 reserved 0 reserved
1 PKIX X.509 as per PKIX 1 PKIX X.509 as per PKIX
2 SPKI SPKI certificate 2 SPKI SPKI certificate
3 PGP OpenPGP packet 3 PGP OpenPGP packet
4 IPKIX The URL of an X.509 data object 4 IPKIX The URL of an X.509 data object
5 ISPKI The URL of an SPKI certificate 5 ISPKI The URL of an SPKI certificate
6 IPGP The URL of an OpenPGP packet 6 IPGP The URL of an OpenPGP packet
7-252 available for IANA assignment 7 ACPKIX Attribute Certificate
8 IACPKIX The URL of an Attribute Certificate
9-252 available for IANA assignment
253 URI URI private 253 URI URI private
254 OID OID private 254 OID OID private
255-65023 available for IANA assignment 255-65023 available for IANA assignment
65024-65534 experimental 65024-65534 experimental
65535 reserved 65535 reserved
These values represent the initial content of the IANA registry, see
section 8.
The PKIX type is reserved to indicate an X.509 certificate conforming The PKIX type is reserved to indicate an X.509 certificate conforming
to the profile defined by the IETF PKIX working group [9]. The to the profile defined by the IETF PKIX working group [9]. The
certificate section will start with a one-byte unsigned OID length certificate section will start with a one-octet unsigned OID length
and then an X.500 OID indicating the nature of the remainder of the and then an X.500 OID indicating the nature of the remainder of the
certificate section (see 2.3 below). (NOTE: X.509 certificates do certificate section (see 2.3 below). (NOTE: X.509 certificates do
not include their X.500 directory type designating OID as a prefix.) not include their X.500 directory type designating OID as a prefix.)
The SPKI type is reserved to indicate the SPKI certificate format The SPKI type is reserved to indicate the SPKI certificate format
[14], for use when the SPKI documents are moved from experimental [15], for use when the SPKI documents are moved from experimental
status. status.
The PGP type indicates an OpenPGP packet as described in [6] and its The PGP type indicates an OpenPGP packet as described in [6] and its
extensions and successors. Two uses are to transfer public key extensions and successors. Two uses are to transfer public key
material and revocation signatures. The data is binary, and MUST NOT material and revocation signatures. The data is binary, and MUST NOT
be encoded into an ASCII armor. An implementation SHOULD process be encoded into an ASCII armor. An implementation SHOULD process
transferable public keys as described in section 10.1 of [6], but it transferable public keys as described in section 10.1 of [6], but it
MAY handle additional OpenPGP packets. MAY handle additional OpenPGP packets.
The IPKIX, ISPKI and IPGP types indicate a URL which will serve the The ACPKIX type indicate an Attribute Certificate format [10].
content that would have been in the "certificate, CRL or URL" field
of the corresponding types; PKIX, SPKI or PGP, respectively. The The IPKIX, ISPKI, IPGP, IACPKIX types indicate a URL which will serve
IPKIX, ISPKI and IPGP types are known as "indirect". These types the content that would have been in the "certificate, CRL or URL"
MUST be used when the content is too large to fit in the CERT RR, and field of the corresponding types; PKIX, SPKI, PGP, or ACPKIX
MAY be used at the implementer's discretion. They SHOULD NOT be used respectively. The IPKIX, ISPKI, IPGP and IACPKIX types are known as
where the DNS message is 512 bytes or smaller, and could thus be "indirect". These types MUST be used when the content is too large
expected to fit a UDP packet. to fit in the CERT RR, and MAY be used at the implementer's
discretion. They SHOULD NOT be used where the DNS message is 512
octets or smaller, and could thus be expected to fit a UDP packet.
The URI private type indicates a certificate format defined by an The URI private type indicates a certificate format defined by an
absolute URI. The certificate portion of the CERT RR MUST begin with absolute URI. The certificate portion of the CERT RR MUST begin with
a null terminated URI [5] and the data after the null is the private a null terminated URI [5] and the data after the null is the private
format certificate itself. The URI SHOULD be such that a retrieval format certificate itself. The URI SHOULD be such that a retrieval
from it will lead to documentation on the format of the certificate. from it will lead to documentation on the format of the certificate.
Recognition of private certificate types need not be based on URI Recognition of private certificate types need not be based on URI
equality but can use various forms of pattern matching so that, for equality but can use various forms of pattern matching so that, for
example, subtype or version information can also be encoded into the example, subtype or version information can also be encoded into the
URI. URI.
The OID private type indicates a private format certificate specified The OID private type indicates a private format certificate specified
by an ISO OID prefix. The certificate section will start with a one- by an ISO OID prefix. The certificate section will start with a one-
byte unsigned OID length and then a BER encoded OID indicating the octet unsigned OID length and then a BER encoded OID indicating the
nature of the remainder of the certificate section. This can be an nature of the remainder of the certificate section. This can be an
X.509 certificate format or some other format. X.509 certificates X.509 certificate format or some other format. X.509 certificates
that conform to the IETF PKIX profile SHOULD be indicated by the PKIX that conform to the IETF PKIX profile SHOULD be indicated by the PKIX
type, not the OID private type. Recognition of private certificate type, not the OID private type. Recognition of private certificate
types need not be based on OID equality but can use various forms of types need not be based on OID equality but can use various forms of
pattern matching such as OID prefix. pattern matching such as OID prefix.
2.2. Text Representation of CERT RRs 2.2. Text Representation of CERT RRs
The RDATA portion of a CERT RR has the type field as an unsigned The RDATA portion of a CERT RR has the type field as an unsigned
decimal integer or as a mnemonic symbol as listed in section 2.1 decimal integer or as a mnemonic symbol as listed in section 2.1
above. above.
The key tag field is represented as an unsigned decimal integer. The key tag field is represented as an unsigned decimal integer.
The algorithm field is represented as an unsigned decimal integer or The algorithm field is represented as an unsigned decimal integer or
a mnemonic symbol as listed in [11]. a mnemonic symbol as listed in [12].
The certificate / CRL portion is represented in base 64 [15] and may The certificate / CRL portion is represented in base 64 [16] and may
be divided up into any number of white space separated substrings, be divided up into any number of white space separated substrings,
down to single base 64 digits, which are concatenated to obtain the down to single base 64 digits, which are concatenated to obtain the
full signature. These substrings can span lines using the standard full signature. These substrings can span lines using the standard
parenthesis. parenthesis.
Note that the certificate / CRL portion may have internal sub-fields, Note that the certificate / CRL portion may have internal sub-fields,
but these do not appear in the master file representation. For but these do not appear in the master file representation. For
example, with type 254, there will be an OID size, an OID, and then example, with type 254, there will be an OID size, an OID, and then
the certificate / CRL proper. But only a single logical base 64 the certificate / CRL proper. But only a single logical base 64
string will appear in the text representation. string will appear in the text representation.
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2. 201.13.251.10.in-addr.arpa, and 2. 201.13.251.10.in-addr.arpa, and
3. hacker.mail.widget.foo.example. 3. hacker.mail.widget.foo.example.
3.2. Purpose-based X.509 CERT RR Names 3.2. Purpose-based X.509 CERT RR Names
Due to the difficulty for clients that do not already possess a Due to the difficulty for clients that do not already possess a
certificate to reconstruct the content-based owner name, purpose- certificate to reconstruct the content-based owner name, purpose-
based owner names are recommended in this section. Recommendations based owner names are recommended in this section. Recommendations
for purpose-based owner names vary per scenario. The following table for purpose-based owner names vary per scenario. The following table
summarizes the purpose-based X.509 CERT RR owner name guidelines for summarizes the purpose-based X.509 CERT RR owner name guidelines for
use with S/MIME [16], SSL/TLS [12], and IPSEC [13]: use with S/MIME [17], SSL/TLS [13], and IPsec [14]:
Scenario Owner name Scenario Owner name
------------------ ---------------------------------------------- ------------------ ----------------------------------------------
S/MIME Certificate Standard translation of an RFC 2822 email S/MIME Certificate Standard translation of an RFC 2822 email
address. Example: An S/MIME certificate for address. Example: An S/MIME certificate for
"postmaster@example.org" will use a standard "postmaster@example.org" will use a standard
hostname translation of the owner name, hostname translation of the owner name,
"postmaster.example.org". "postmaster.example.org".
TLS Certificate Hostname of the TLS server. TLS Certificate Hostname of the TLS server.
IPSEC Certificate Hostname of the IPSEC machine and/or, for IPv4 IPsec Certificate Hostname of the IPsec machine and/or, for IPv4
or IPv6 addresses, the fully qualified domain or IPv6 addresses, the fully qualified domain
name in the appropriate reverse domain. name in the appropriate reverse domain.
An alternate approach for IPSEC is to store raw public keys [17]. An alternate approach for IPsec is to store raw public keys [18].
3.3. Content-based OpenPGP CERT RR Names 3.3. Content-based OpenPGP CERT RR Names
OpenPGP signed keys (certificates) use a general character string OpenPGP signed keys (certificates) use a general character string
User ID [6]. However, it is recommended by OpenPGP that such names User ID [6]. However, it is recommended by OpenPGP that such names
include the RFC 2822 [8] email address of the party, as in "Leslie include the RFC 2822 [8] email address of the party, as in "Leslie
Example <Leslie@host.example>". If such a format is used, the CERT Example <Leslie@host.example>". If such a format is used, the CERT
ought to be under the standard translation of the email address into ought to be under the standard translation of the email address into
a domain name, which would be leslie.host.example in this case. If a domain name, which would be leslie.host.example in this case. If
no RFC 2822 name can be extracted from the string name, no specific no RFC 2822 name can be extracted from the string name, no specific
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3.4. Purpose-based OpenPGP CERT RR Names 3.4. Purpose-based OpenPGP CERT RR Names
Applications that receive an OpenPGP packet containing encrypted or Applications that receive an OpenPGP packet containing encrypted or
signed data but do not know the email address of the sender will have signed data but do not know the email address of the sender will have
difficulties constructing the correct owner name and cannot use the difficulties constructing the correct owner name and cannot use the
content-based owner name guidelines. However, these clients commonly content-based owner name guidelines. However, these clients commonly
know the key fingerprint or the Key ID. The key ID is found in know the key fingerprint or the Key ID. The key ID is found in
OpenPGP packets, and the key fingerprint is commonly found in OpenPGP packets, and the key fingerprint is commonly found in
auxiliary data that may be available. In this case, use of an owner auxiliary data that may be available. In this case, use of an owner
name identical to the key fingerprint and the key ID expressed in name identical to the key fingerprint and the key ID expressed in
hexadecimal [15] is recommended. Example: hexadecimal [16] is recommended. Example:
$ORIGIN example.org. $ORIGIN example.org.
0424D4EE81A0E3D119C6F835EDA21E94B565716F IN CERT PGP ... 0424D4EE81A0E3D119C6F835EDA21E94B565716F IN CERT PGP ...
F835EDA21E94B565716F IN CERT PGP ... F835EDA21E94B565716F IN CERT PGP ...
B565716F IN CERT PGP ... B565716F IN CERT PGP ...
If the same key material is stored for several owner names, the use If the same key material is stored for several owner names, the use
of CNAME may help to avoid data duplication. Note that CNAME is not of CNAME may help to avoid data duplication. Note that CNAME is not
always applicable, because it maps one owner name to the other for always applicable, because it maps one owner name to the other for
all purposes, which may be sub-optimal when two keys with the same all purposes, which may be sub-optimal when two keys with the same
Key ID are stored. Key ID are stored.
3.5. Owner names for IPKIX, ISPKI, and IPGP 3.5. Owner names for IPKIX, ISPKI, IPGP, and IACPKIX
These types are stored under the same owner names, both purpose- and These types are stored under the same owner names, both purpose- and
content-based, as the PKIX, SPKI and PGP types. content-based, as the PKIX, SPKI, PGP and ACPKIX types.
4. Performance Considerations 4. Performance Considerations
The Domain Name System (DNS) protocol was designed for small The Domain Name System (DNS) protocol was designed for small
transfers, typically below 512 bytes. While larger transfers will transfers, typically below 512 octets. While larger transfers will
perform correctly and work is underway to make larger transfers more perform correctly and work is underway to make larger transfers more
efficient, it is still advisable at this time to make every efficient, it is still advisable at this time to make every
reasonable effort to minimize the size of certificates stored within reasonable effort to minimize the size of certificates stored within
the DNS. Steps that can be taken may include using the fewest the DNS. Steps that can be taken may include using the fewest
possible optional or extension fields and using short field values possible optional or extension fields and using short field values
for necessary variable length fields. for necessary variable length fields.
The RDATA field in the DNS protocol may only hold data of size 65535 The RDATA field in the DNS protocol may only hold data of size 65535
octets (64kb) or less. This means that each CERT RR MUST NOT contain octets (64kb) or less. This means that each CERT RR MUST NOT contain
more than 64kb of payload, even if the corresponding certificate or more than 64kb of payload, even if the corresponding certificate or
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The majority of this document is copied verbatim from RFC 2538, by The majority of this document is copied verbatim from RFC 2538, by
Donald Eastlake 3rd and Olafur Gudmundsson. Donald Eastlake 3rd and Olafur Gudmundsson.
6. Acknowledgements 6. Acknowledgements
Thanks to David Shaw and Michael Graff for their contributions to Thanks to David Shaw and Michael Graff for their contributions to
earlier works that motivated, and served as inspiration for, this earlier works that motivated, and served as inspiration for, this
document. document.
This document was improved by suggestions and comments from Olivier This document was improved by suggestions and comments from Olivier
Dubuisson, Peter Koch, Olaf M. Kolkman, Ben Laurie, Edward Lewis, Dubuisson, Scott Hollenbeck, Russ Housley, Peter Koch, Olaf M.
Kolkman, Ben Laurie, Edward Lewis, John Loughney, Allison Mankin,
Douglas Otis, Marcos Sanz, Pekka Savola, Jason Sloderbeck, Samuel Douglas Otis, Marcos Sanz, Pekka Savola, Jason Sloderbeck, Samuel
Weiler, and Florian Weimer. No doubt the list is incomplete. We Weiler, and Florian Weimer. No doubt the list is incomplete. We
apologize to anyone we left out. apologize to anyone we left out.
7. Security Considerations 7. Security Considerations
By definition, certificates contain their own authenticating By definition, certificates contain their own authenticating
signature. Thus, it is reasonable to store certificates in non- signature. Thus, it is reasonable to store certificates in non-
secure DNS zones or to retrieve certificates from DNS with DNS secure DNS zones or to retrieve certificates from DNS with DNS
security checking not implemented or deferred for efficiency. The security checking not implemented or deferred for efficiency. The
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Decimal Type Meaning Reference Decimal Type Meaning Reference
------- ---- ------- --------- ------- ---- ------- ---------
0 Reserved RFC xxxx 0 Reserved RFC xxxx
1 PKIX X.509 as per PKIX RFC xxxx 1 PKIX X.509 as per PKIX RFC xxxx
2 SPKI SPKI certificate RFC xxxx 2 SPKI SPKI certificate RFC xxxx
3 PGP OpenPGP packet RFC xxxx 3 PGP OpenPGP packet RFC xxxx
4 IPKIX The URL of an X.509 data object RFC xxxx 4 IPKIX The URL of an X.509 data object RFC xxxx
5 ISPKI The URL of an SPKI certificate RFC xxxx 5 ISPKI The URL of an SPKI certificate RFC xxxx
6 IPGP The URL of an OpenPGP packet RFC xxxx 6 IPGP The URL of an OpenPGP packet RFC xxxx
7-252 Available for IANA assignment 7 ACPKIX Attribute Certificate RFC xxxx
8 IACPKIX The URL of an Attribute Certificate RFC xxxx
9-252 Available for IANA assignment
by IETF Standards action by IETF Standards action
253 URI URI private RFC xxxx 253 URI URI private RFC xxxx
254 OID OID private RFC xxxx 254 OID OID private RFC xxxx
255-65023 Available for IANA assignment 255-65023 Available for IANA assignment
by IETF Consensus by IETF Consensus
65024-65534 Experimental RFC xxxx 65024-65534 Experimental RFC xxxx
65535 Reserved RFC xxxx 65535 Reserved RFC xxxx
Certificate types 0x0000 through 0x00FF and 0xFF00 through 0xFFFF can Certificate types 0x0000 through 0x00FF and 0xFF00 through 0xFFFF can
only be assigned by an IETF standards action [7]. This document only be assigned by an IETF standards action [7]. This document
assigns 0x0001 through 0x0006 and 0x00FD and 0x00FE. Certificate assigns 0x0001 through 0x0008 and 0x00FD and 0x00FE. Certificate
types 0x0100 through 0xFEFF are assigned through IETF Consensus [7] types 0x0100 through 0xFEFF are assigned through IETF Consensus [7]
based on RFC documentation of the certificate type. The availability based on RFC documentation of the certificate type. The availability
of private types under 0x00FD and 0x00FE ought to satisfy most of private types under 0x00FD and 0x00FE ought to satisfy most
requirements for proprietary or private types. requirements for proprietary or private types.
The CERT RR reuses the DNS Security Algorithm Numbers registry. In The CERT RR reuses the DNS Security Algorithm Numbers registry. In
particular, the CERT RR requires that algorithm number 0 remain particular, the CERT RR requires that algorithm number 0 remain
reserved, as described in Section 2. The IANA is directed to reserved, as described in Section 2. The IANA is directed to
reference the CERT RR as a user of this registry and value 0, in reference the CERT RR as a user of this registry and value 0, in
particular. particular.
skipping to change at page 13, line 17 skipping to change at page 13, line 26
terminology. Improve reference for Key Tag Algorithm terminology. Improve reference for Key Tag Algorithm
calculations. calculations.
6. Add examples that suggest use of CNAME to reduce bandwidth. 6. Add examples that suggest use of CNAME to reduce bandwidth.
7. In section 3, appended the last paragraphs that discuss 7. In section 3, appended the last paragraphs that discuss
"content-based" vs "purpose-based" owner names. Add section 3.2 "content-based" vs "purpose-based" owner names. Add section 3.2
for purpose-based X.509 CERT owner names, and section 3.4 for for purpose-based X.509 CERT owner names, and section 3.4 for
purpose-based OpenPGP CERT owner names. purpose-based OpenPGP CERT owner names.
8. Added size considerations. 8. Added size considerations.
9. The SPKI types has been reserved, until RFC 2692/2693 is moved 9. The SPKI types has been reserved, until RFC 2692/2693 is moved
from the experimental status. from the experimental status.
10. Added indirect types IPKIX, ISPKI, and IPGP. 10. Added indirect types IPKIX, ISPKI, IPGP, and IACPKIX.
11. An IANA registry of CERT type values was created.
Appendix A. Copying conditions Appendix A. Copying conditions
Regarding the portion of this document that was written by Simon Regarding the portion of this document that was written by Simon
Josefsson ("the author", for the remainder of this section), the Josefsson ("the author", for the remainder of this section), the
author makes no guarantees and is not responsible for any damage author makes no guarantees and is not responsible for any damage
resulting from its use. The author grants irrevocable permission to resulting from its use. The author grants irrevocable permission to
anyone to use, modify, and distribute it in any way that does not anyone to use, modify, and distribute it in any way that does not
diminish the rights of anyone else to use, modify, and distribute it, diminish the rights of anyone else to use, modify, and distribute it,
provided that redistributed derivative works do not contain provided that redistributed derivative works do not contain
skipping to change at page 14, line 18 skipping to change at page 14, line 29
[7] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [7] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 1998.
[8] Resnick, P., "Internet Message Format", RFC 2822, April 2001. [8] Resnick, P., "Internet Message Format", RFC 2822, April 2001.
[9] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 [9] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509
Public Key Infrastructure Certificate and Certificate Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile", RFC 3280, April 2002. Revocation List (CRL) Profile", RFC 3280, April 2002.
[10] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, [10] Farrell, S. and R. Housley, "An Internet Attribute Certificate
Profile for Authorization", RFC 3281, April 2002.
[11] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"DNS Security Introduction and Requirements", RFC 4033, "DNS Security Introduction and Requirements", RFC 4033,
March 2005. March 2005.
[11] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, [12] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"Resource Records for the DNS Security Extensions", RFC 4034, "Resource Records for the DNS Security Extensions", RFC 4034,
March 2005. March 2005.
10.2. Informative References 10.2. Informative References
[12] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", [13] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999. RFC 2246, January 1999.
[13] Kent, S. and R. Atkinson, "Security Architecture for the [14] Kent, S. and R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998. Internet Protocol", RFC 2401, November 1998.
[14] Ellison, C., Frantz, B., Lampson, B., Rivest, R., Thomas, B., [15] Ellison, C., Frantz, B., Lampson, B., Rivest, R., Thomas, B.,
and T. Ylonen, "SPKI Certificate Theory", RFC 2693, and T. Ylonen, "SPKI Certificate Theory", RFC 2693,
September 1999. September 1999.
[15] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", [16] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings",
RFC 3548, July 2003. RFC 3548, July 2003.
[16] Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions [17] Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions
(S/MIME) Version 3.1 Message Specification", RFC 3851, (S/MIME) Version 3.1 Message Specification", RFC 3851,
July 2004. July 2004.
[17] Richardson, M., "A Method for Storing IPsec Keying Material in [18] Richardson, M., "A Method for Storing IPsec Keying Material in
DNS", RFC 4025, March 2005. DNS", RFC 4025, March 2005.
Author's Address Author's Address
Simon Josefsson Simon Josefsson
Email: simon@josefsson.org Email: simon@josefsson.org
Intellectual Property Statement Intellectual Property Statement
 End of changes. 

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