draft-ietf-dnsop-dnssec-operational-practices-01.txt   draft-ietf-dnsop-dnssec-operational-practices-02.txt 
DNSOP O. Kolkman DNSOP O. Kolkman
Internet-Draft RIPE NCC Internet-Draft RIPE NCC
Expires: August 30, 2004 R. Gieben Expires: April 11, 2005 R. Gieben
NLnet Labs NLnet Labs
March 2004 October 11, 2004
DNSSEC Operational Practices DNSSEC Operational Practices
draft-ietf-dnsop-dnssec-operational-practices-01.txt draft-ietf-dnsop-dnssec-operational-practices-02.txt
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Abstract Abstract
This document describes a set of practices for operating a DNSSEC This document describes a set of practices for operating a DNSSEC
aware environment. The target audience is zone administrators aware environment. The target audience is zone administrators
deploying DNSSEC that need a guide to help them chose appropriate deploying DNSSEC that need a guide to help them chose appropriate
values for DNSSEC parameters. It also discusses operational matters values for DNSSEC parameters. It also discusses operational matters
such as key rollovers, KSK and ZSK considerations and related such as key rollovers, KSK and ZSK considerations and related
matters. matters.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 The Use of the Term 'key' . . . . . . . . . . . . . . . . 3 1.1 The Use of the Term 'key' . . . . . . . . . . . . . . . . 3
1.2 Keeping the Chain of Trust Intact . . . . . . . . . . . . 3 1.2 Keeping the Chain of Trust Intact . . . . . . . . . . . . 3
2. Time in DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Time in DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Time Definitions . . . . . . . . . . . . . . . . . . . . . 4 2.1 Time Definitions . . . . . . . . . . . . . . . . . . . . . 4
2.2 Time Considerations . . . . . . . . . . . . . . . . . . . 5 2.2 Time Considerations . . . . . . . . . . . . . . . . . . . 5
3. Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Motivations for the KSK and ZSK Functions . . . . . . . . 7 3.1 Motivations for the KSK and ZSK Separation . . . . . . . . 7
3.2 Key Security Considerations . . . . . . . . . . . . . . . 8 3.2 Key Security Considerations . . . . . . . . . . . . . . . 8
3.2.1 Key Validity Period . . . . . . . . . . . . . . . . . 8 3.2.1 Key Validity Period . . . . . . . . . . . . . . . . . 8
3.2.2 Key Algorithm . . . . . . . . . . . . . . . . . . . . 8 3.2.2 Key Algorithm . . . . . . . . . . . . . . . . . . . . 8
3.2.3 Key Sizes . . . . . . . . . . . . . . . . . . . . . . 8 3.2.3 Key Sizes . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Key Rollovers . . . . . . . . . . . . . . . . . . . . . . 9 3.3 Key Rollovers . . . . . . . . . . . . . . . . . . . . . . 9
3.3.1 Zone-signing Key Rollovers . . . . . . . . . . . . . . 10 3.3.1 Difference Between ZSK and KSK Rollovers . . . . . . . 10
3.3.2 Key-signing Key Rollovers . . . . . . . . . . . . . . 13 3.3.2 Zone-signing Key Rollovers . . . . . . . . . . . . . . 10
4. Planning for Emergency Key Rollover . . . . . . . . . . . . . 14 3.3.3 Key-signing Key Rollovers . . . . . . . . . . . . . . 14
4.1 KSK Compromise . . . . . . . . . . . . . . . . . . . . . . 15 3.3.4 Automated Key Rollovers . . . . . . . . . . . . . . . 15
4.2 ZSK Compromise . . . . . . . . . . . . . . . . . . . . . . 15 4. Planning for Emergency Key Rollover . . . . . . . . . . . . . 15
4.1 KSK Compromise . . . . . . . . . . . . . . . . . . . . . . 16
4.2 ZSK Compromise . . . . . . . . . . . . . . . . . . . . . . 16
4.3 Compromises of Keys Anchored in Resolvers . . . . . . . . 16 4.3 Compromises of Keys Anchored in Resolvers . . . . . . . . 16
5. Parental Policies . . . . . . . . . . . . . . . . . . . . . . 16 5. Parental Policies . . . . . . . . . . . . . . . . . . . . . . 17
5.1 Initial Key Exchanges and Parental Policies 5.1 Initial Key Exchanges and Parental Policies
Considerations . . . . . . . . . . . . . . . . . . . . . . 16 Considerations . . . . . . . . . . . . . . . . . . . . . . 17
5.2 Storing Keys So Hashes Can Be Regenerated . . . . . . . . 16 5.2 Storing Keys So Hashes Can Be Regenerated . . . . . . . . 17
5.3 Security Lameness Checks . . . . . . . . . . . . . . . . . 17 5.3 Security Lameness Checks . . . . . . . . . . . . . . . . . 18
5.4 DS Signature Validity Period . . . . . . . . . . . . . . . 17 5.4 DS Signature Validity Period . . . . . . . . . . . . . . . 18
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 6. Security Considerations . . . . . . . . . . . . . . . . . . . 18
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.1 Normative References . . . . . . . . . . . . . . . . . . . . 18 8.1 Normative References . . . . . . . . . . . . . . . . . . . . 19
8.2 Informative References . . . . . . . . . . . . . . . . . . . 18 8.2 Informative References . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 20
A. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 19 A. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 20
B. Zone-signing Key Rollover Howto . . . . . . . . . . . . . . . 20 B. Zone-signing Key Rollover Howto . . . . . . . . . . . . . . . 21
C. Typographic Conventions . . . . . . . . . . . . . . . . . . . 20 C. Typographic Conventions . . . . . . . . . . . . . . . . . . . 22
D. Document Details and Changes . . . . . . . . . . . . . . . . . 22 D. Document Details and Changes . . . . . . . . . . . . . . . . . 23
D.1 draft-ietf-dnsop-dnssec-operational-practices-00 . . . . . 22 D.1 draft-ietf-dnsop-dnssec-operational-practices-00 . . . . . 23
D.2 draft-ietf-dnsop-dnssec-operational-practices-01 . . . . . 22 D.2 draft-ietf-dnsop-dnssec-operational-practices-01 . . . . . 23
Intellectual Property and Copyright Statements . . . . . . . . 23 Intellectual Property and Copyright Statements . . . . . . . . 25
1. Introduction 1. Introduction
During workshops and early operational deployment tests, operators During workshops and early operational deployment tests, operators
and system administrators gained experience about operating DNSSEC and system administrators gained experience about operating DNSSEC
aware DNS services. This document translates these experiences into aware DNS services. This document translates these experiences into
a set of practices for zone administrators. At the time of writing, a set of practices for zone administrators. At the time of writing,
there exists very little experience with DNSSEC in production there exists very little experience with DNSSEC in production
environments, this document should therefore explicitly not be seen environments, this document should therefore explicitly not be seen
as represented 'Best Current Practices'. as representing 'Best Current Practices'.
The procedures herein are focused on the maintenance of signed zones The procedures herein are focused on the maintenance of signed zones
(i.e. signing and publishing zones on authoritative servers). It is (i.e. signing and publishing zones on authoritative servers). It is
intended that maintenance of zones such as resigning or key rollovers intended that maintenance of zones such as resigning or key rollovers
be transparent to any verifying clients on the Internet. be transparent to any verifying clients on the Internet.
The structure of this document is as follows: It begins with The structure of this document is as follows: It begins with
discussing some of the considerations with respect to timing discussing some of the considerations with respect to timing
parameters of DNS in relation to DNSSEC (Section 2). Aspects of key parameters of DNS in relation to DNSSEC (Section 2). Aspects of key
management such as key rollover schemes are described in Section 3. management such as key rollover schemes are described in Section 3.
Emergency rollover considerations are addressed in Section 4. The Emergency rollover considerations are addressed in Section 4. The
typographic conventions used in this document are explained in typographic conventions used in this document are explained in
Appendix C. Appendix C.
Since this is a document with operational suggestions and there are Since this is a document with operational suggestions and there are
no protocol specifications, the RFC2119 [5] language does not apply. no protocol specifications, the RFC2119 [7] language does not apply.
1.1 The Use of the Term 'key' 1.1 The Use of the Term 'key'
It is assumed that the reader is familiar with the concept of It is assumed that the reader is familiar with the concept of
asymmetric keys on which DNSSEC is based (Public Key Cryptography asymmetric keys on which DNSSEC is based (Public Key Cryptography
[Ref to Schneider?]). Therefore, this document will use the term [11]). Therefore, this document will use the term 'key' rather
'key' rather loosely. Where it is written that 'a key is used to sign loosely. Where it is written that 'a key is used to sign data' it is
data' it is assumed that the reader understands that it is the assumed that the reader understands that it is the private part of
private part of the key-pair that is used for signing. It is also the key-pair that is used for signing. It is also assumed that the
assumed that the reader understands that the public part of the reader understands that the public part of the key-pair is published
key-pair is published in the DNSKEY resource record and that it is in the DNSKEY resource record and that it is the public part that is
used in key-exchanges. used in key-exchanges.
1.2 Keeping the Chain of Trust Intact 1.2 Keeping the Chain of Trust Intact
Maintaining a valid chain of trust is important because broken chains Maintaining a valid chain of trust is important because broken chains
of trust will result in data being marked as bogus, which may cause of trust will result in data being marked as bogus, which may cause
entire (sub)domains to become invisible to verifying clients. The entire (sub)domains to become invisible to verifying clients. The
administrators of secured zones have to realise that their zone is, administrators of secured zones have to realize that their zone is,
to their clients, part of a chain of trust. to their clients, part of a chain of trust.
As mentioned in the introduction, the procedures herein are intended As mentioned in the introduction, the procedures herein are intended
to ensure maintenance of zones, such as resigning or key rollovers, to ensure maintenance of zones, such as resigning or key rollovers,
be transparent to the verifying clients on the Internet. be transparent to the verifying clients on the Internet.
Administrators of secured zones will have to keep in mind that data Administrators of secured zones will have to keep in mind that data
published on an authoritative primary server will not be immediately published on an authoritative primary server will not be immediately
seen by verifying clients; it may take some time for the data to be seen by verifying clients; it may take some time for the data to be
transfered to other secondary authoritative nameservers, during which transfered to other secondary authoritative nameservers, during which
period clients may be fetching data from caching non-authoritative period clients may be fetching data from caching non-authoritative
servers. For the verifying clients it is important that data from servers.
secured zones can be used to build chains of trust regardless of
whether the data came directly from an authoritative server, a For the verifying clients it is important that data from secured
caching nameserver or some middle box. Only by carefully using the zones can be used to build chains of trust regardless of whether the
available timing parameters can a zone administrator assure that the data came directly from an authoritative server, a caching nameserver
data necessary for verification can be obtained. or some middle box. Only by carefully using the available timing
parameters can a zone administrator assure that the data necessary
for verification can be obtained.
The responsibility for maintaining the chain of trust is shared by The responsibility for maintaining the chain of trust is shared by
administrators of secured zones in the chain of trust. This is most administrators of secured zones in the chain of trust. This is most
obvious in the case of a 'key compromise' when a trade off between obvious in the case of a 'key compromise' when a trade off between
maintaining a valid chain of trust and the fact that the key has been maintaining a valid chain of trust and replacing the compromised keys
stolen, must be made. as soon as possible, must be made.
The zone administrator will have to make a tradeoff between keeping The zone administrator will have to make a tradeoff between keeping
the chain of trust intact -thereby allowing for attacks with the the chain of trust intact -thereby allowing for attacks with the
compromised key- or to deliberately break the chain of trust thereby compromised key - or to deliberately break the chain of trust and
making secured subdomains invisible to security aware resolvers. Also making secured sub domains invisible to security aware resolvers.
see Section 4. Also see Section 4.
2. Time in DNSSEC 2. Time in DNSSEC
Without DNSSEC all times in DNS are relative. The SOA's refresh, Without DNSSEC all times in DNS are relative. The SOA's refresh,
retry and expiration timers are counters that are used to determine retry and expiration timers are counters that are used to determine
the time elapsed after a slave server syncronised (or tried to the time elapsed after a slave server synchronized (or tried to
syncronise) with a master server. The Time to Live (TTL) value and synchronize) with a master server. The Time to Live (TTL) value and
the SOA minimum TTL parameter [6] are used to determine how long a the SOA minimum TTL parameter [8] are used to determine how long a
forwarder should cache data after it has been fetched from an forwarder should cache data after it has been fetched from an
authoritative server. DNSSEC introduces the notion of an absolute authoritative server. By using a signature validity period, DNSSEC
time in the DNS. Signatures in DNSSEC have an expiration date after introduces the notion of an absolute time in the DNS. Signatures in
which the signature is marked as invalid and the signed data is to be DNSSEC have an expiration date after which the signature is marked as
considered bogus. invalid and the signed data is to be considered bogus.
2.1 Time Definitions 2.1 Time Definitions
In this document we will be using a number of time related terms. In this document we will be using a number of time related terms.
Within the context of this document the following definitions apply: The following definitions apply:
o "Signature validity period" o "Signature validity period"
The period that a signature is valid. It starts at the time The period that a signature is valid. It starts at the time
specified in the signature inception field of the RRSIG RR and specified in the signature inception field of the RRSIG RR and
ends at the time specified in the expiration field of the RRSIG ends at the time specified in the expiration field of the RRSIG
RR. RR.
o "Signature publication period" o "Signature publication period"
Time after which a signature (made with a specific key) is Time after which a signature (made with a specific key) is
replaced with a new signature (made with the same key). This replaced with a new signature (made with the same key). This
replacement takes place by publishing the relevant RRSIG in the replacement takes place by publishing the relevant RRSIG in the
master zone file. If a signature is published at time T0 and a master zone file.
new signature is published at time T1, the signature
publication period is T1 - T0.
If all signatures are refreshed at zone (re)signing then the If all signatures are refreshed at zone (re)signing then the
signature publication period is equal signature validity signature publication period is equal to the signature validity
period. period.
o "Maximum/Minimum Zone TTL" o "Maximum/Minimum Zone TTL"
The maximum or minimum value of all the TTLs in a zone. The maximum or minimum value of the TTLs from the complete set
of RRs in a zone.
2.2 Time Considerations 2.2 Time Considerations
Because of the expiration of signatures, one should consider the Because of the expiration of signatures, one should consider the
following. following.
o The Maximum Zone TTL of your zone data should be a fraction of o We suggest the Maximum Zone TTL of your zone data to be a fraction
your signature validity period. of your signature validity period.
If the TTL would be of similar order as the signature validity If the TTL would be of similar order as the signature validity
period, then all RRsets fetched during the validity period period, then all RRsets fetched during the validity period
would be cached until the signature expiration time. As a would be cached until the signature expiration time. Section
result query load on authoritative servers would peak at 7.1 [5] suggests that "the resolver may use the time remaining
signature expiration time. before expiration of the signature validity period of a signed
RRset as an upper bound for the TTL". As a result query load
on authoritative servers would peak at signature expiration
time, as this is also the time at which records simultaneously
expire from caches.
To avoid query load peaks we suggest the TTL on all the RRs in To avoid query load peaks we suggest the TTL on all the RRs in
your zone to be at least a few times smaller than your your zone to be at least a few times smaller than your
signature validity period. signature validity period.
o The signature publication period should be at least one maximum o We suggest the signature publication period to be at least one
TTL smaller than the signature validity period. maximum TTL smaller than the signature validity period.
Resigning a zone shortly before the end of the signature Resigning a zone shortly before the end of the signature
validity period may cause simultaneous expiration of data from validity period may cause simultaneous expiration of data from
caches. This in turn may lead to peaks in the load on caches. This in turn may lead to peaks in the load on
authoritative servers. authoritative servers.
o The Minimum zone TTL should be long enough to both fetch and o We suggest the minimum zone TTL to be long enough to both fetch
verify all the RRs in the authentication chain. and verify all the RRs in the authentication chain. A low TTL can
cause two problems:
1. During validation, some data may expire before the 1. During validation, some data may expire before the
validation is complete. The validator should be able to keep validation is complete. The validator should be able to keep
all data, until is completed. This applies to all RRs needed all data, until is completed. This applies to all RRs needed
to complete the chain of trust: DSs, DNSKEYs, RRSIGs, and to complete the chain of trust: DSs, DNSKEYs, RRSIGs, and the
the final answers i.e. the RR that is returned for the final answers i.e. the RR set that is returned for the initial
initial query. query.
2. Frequent verification causes load on recursive 2. Frequent verification causes load on recursive nameservers.
nameservers. Data at delegation points, DSs, DNSKEYs and Data at delegation points, DSs, DNSKEYs and RRSIGs benefit from
RRSIGs benefit from caching. The TTL on those should be caching. The TTL on those should be relatively long.
relatively long.
We have seen events where data needed for verification of an
authentication chain had expired from caches.
We suggest the TTL on DNSKEY and DSs to be between ten minutes
and one hour. We recommend zone administrators to chose TTLs
longer than half a minute.
[Editor's Note: this observation could be implementation
specific. We are not sure if we should leave this item]
o Slave servers will need to be able to fetch newly signed zones o Slave servers will need to be able to fetch newly signed zones
well before the data expires from your zone. well before the RRSIGs in the zone server by the slave server pass
'Better no answers than bad answers.' their signature expiration time.
If a properly implemented slave server is not able to contact a When a slave server is out of sync with its master and data in
master server for an extended period the data will at some a zone is signed by expired signatures it may be better for the
point expire and the slave server will not hand out any data. slave server not to give out any answer.
Normally a slave server that is not able to contact a master
server for an extended period will expire a zone. When that
happens the zone will not respond on queries. The time of
expiration is set in the SOA record and is relative to the last
successful refresh between the master and the slave server.
There exists no coupling between the signature expiration of
RRSIGs in the zone and the expire parameter in the SOA.
If the server serves a DNSSEC zone than it may well happen that If the server serves a DNSSEC zone than it may well happen that
the signatures expire well before the SOA expiration timer the signatures expire well before the SOA expiration timer
counts down to zero. It is not possible to completely prevent counts down to zero. It is not possible to completely prevent
this from happening by tweaking the SOA parameters. However, this from happening by tweaking the SOA parameters.
the effects can be minimized where the SOA expiration time is However, the effects can be minimized where the SOA expiration
equal or smaller than the signature validity period. time is equal or smaller than the signature validity period.
The consequence of an authoritative server not being able to The consequence of an authoritative server not being able to
update a zone, whilst that zone includes expired signaturs, is update a zone, whilst that zone includes expired signatures, is
that non-secure resolvers will continue to be able to resolve that non-secure resolvers will continue to be able to resolve
data served by the particular slave servers. Security aware data served by the particular slave servers while security
resolvers will experience problems. aware resolvers will experience problems because of answers
being marked as bogus.
We suggest the SOA expiration timer being approximately one We suggest the SOA expiration timer being approximately one
third or one fourth of the signature validity period. It will third or one fourth of the signature validity period. It will
allow problems with transfers from the master server to be allow problems with transfers from the master server to be
noticed before the actual signature time out. noticed before the actual signature time out.
We suggest that operators of nameservers with slave zones We also suggest that operators of nameservers with slave zones
develop 'watch dogs' to spot upcoming signature expirations in develop 'watch dogs' to spot upcoming signature expirations in
slave zones, and take appropriate action. slave zones, and take appropriate action.
When determining the value for the expiration parameter one has When determining the value for the expiration parameter one has
to take the following into account: What are the chances that to take the following into account: What are the chances that
all my secondary zones expire; How quickly can I reach an all my secondary zones expire; How quickly can I reach an
administrator and load a valid zone? All these arguments are administrator and load a valid zone? All these arguments are
not DNSSEC specific. not DNSSEC specific but may influence the choice of your
signature validity intervals.
3. Keys 3. Keys
In the DNSSEC protocol there is only one type of key, the zone key. The DNSSEC validation protocol does not distinguish between DNSKEYs.
With this key, the data in a zone is signed. All DNSKEYs can be used during the validation. In practice operators
use Key Singing and Zone Signing Keys and use the so called SEP flag
to distinguish between them during operations. The dynamics and
considerations are discussed below.
To make zone re-signing and key rollovers procedures easier to To make zone re-signing and key rollovers procedures easier to
implement, it is possible to use one or more keys as Key Signing Keys implement, it is possible to use one or more keys as Key Signing Keys
(KSK) these keys will only sign the apex DNSKEY RRs in a zone. Other (KSK) these keys will only sign the apex DNSKEY RR set in a zone.
keys can be used to sign all the RRsets in a zone and are referred to Other keys can be used to sign all the RRsets in a zone and are
as Zone Signing Keys (ZSK). In this document we assume that KSKs are referred to as Zone Signing Keys (ZSK). In this document we assume
the subset of keys that are used for key exchanges with the parents that KSKs are the subset of keys that are used for key exchanges with
and potentially for configuration as trusted anchors - the so called the parent and potentially for configuration as trusted anchors - the
Secure Entry Point keys (SEP). In this document we assume a so called Secure Entry Point keys (SEP). In this document we assume
one-to-one mapping between KSK and SEP keys and we assume the SEP a one-to-one mapping between KSK and SEP keys and we assume the SEP
flag [4] to be set on KSKs. flag [4] to be set on KSKs.
3.1 Motivations for the KSK and ZSK Functions 3.1 Motivations for the KSK and ZSK Separation
Differentiating between the KSK to ZSK functions has several Differentiating between the KSK to ZSK functions has several
advantages: advantages:
o Making the KSK stronger (i.e. using more bits in the key material) o The KSK can be made stronger (i.e. using more bits in the key
has little operational impact since it is only used to sign a material). This has little operational impact since it is only
small fraction of the zone data. used to sign a small fraction of the zone data.
o As the KSK is only used to sign a keyset, which is most probably o As the KSK is only used to sign a keyset, which is most probably
updated less frequently than other data in the zone, it can be updated less frequently than other data in the zone, it can be
stored separately from (and thus in a safer location than) the stored separately from and in a safer location than the ZSK.
ZSK.
o A KSK can be used for longer periods. o A KSK can be used for longer periods.
o No parent/child interaction is required when ZSKs are updated. o No parent/child interaction is required when ZSKs are updated.
The KSK is used less than ZSK, once a keyset is signed with the KSK The KSK is used less than ZSK, once a keyset is signed with the KSK
all the keys in the keyset can be used as ZSK. If a ZSK is all the keys in the keyset can be used as ZSK. If a ZSK is
compromised, it can be simply dropped from the keyset. The new keyset compromised, it can be simply dropped from the key set. The new key
is then resigned with the KSK. set is then resigned with the KSK.
Given the assumption that for KSKs the SEP flag is set, the KSK can Given the assumption that for KSKs the SEP flag is set, the KSK can
be distinguished from a ZSK by examining the flag field in the DNSKEY be distinguished from a ZSK by examining the flag field in the DNSKEY
RR. If the flag field is an odd number it is a KSK if it is an even RR. If the flag field is an odd number it is a KSK if it is an even
number it is a ZSK e.g. a value of 256 and a key signing key has 257. number it is a ZSK.
The zone-signing key can be used to sign all the data in a zone on a The zone-signing key can be used to sign all the data in a zone on a
regular basis. When a zone-signing key is to be rolled, no regular basis. When a zone-signing key is to be rolled, no
interaction with the parent is needed. This allows for relatively interaction with the parent is needed. This allows for "Signature
short "Signature Validity Periods". That is, Signature Validity Validity Periods" in the order of days.
Periods of the order of days.
The key-signing key is only to be used to sign the Key RR set from The key-signing key is only to be used to sign the DNSKEY RRs in a
the zone apex. If a key-signing key is to be rolled over, there will zone. If a key-signing key is to be rolled over, there will be
be interactions with parties other than the zone administrator such interactions with parties other than the zone administrator. These
as the registry of the parent zone or administrators of verifying can include the registry of the parent zone or administrators of
resolvers that have the particular key configured as trusted entry verifying resolvers that have the particular key configured as
points. Hence, the "Key Usage Time" of these keys can and should be trusted entry points. Hence, the "Key Usage Time" of these keys can
made much longer. Although, given a long enough key, the "Key Usage and should be made much longer. Although, given a long enough key,
Time" can be on the order of years we suggest to plan for a "Key the "Key Usage Time" can be on the order of years we suggest to plan
Usage Time" of the order of a few months so that a key rollover for a "Key Usage Time" of the order of a few months so that a key
remains an operational routine. rollover remains an operational routine.
3.2 Key Security Considerations 3.2 Key Security Considerations
Keys in DNSSEC have a number of parameters which should all be chosen Keys in DNSSEC have a number of parameters which should all be chosen
with care, the most important once are: size, algorithm and the key with care, the most important once are: size, algorithm and the key
validity period (its lifetime). validity period (its lifetime).
3.2.1 Key Validity Period 3.2.1 Key Validity Period
RFC2541 [2] describes a number of considerations with respect to the RFC2541 [2] describes a number of considerations with respect to the
skipping to change at page 8, line 29 skipping to change at page 8, line 34
transaction keys but suggestions for key sizes are not made. transaction keys but suggestions for key sizes are not made.
If we say long-lived keys are key-signing keys and transactions keys If we say long-lived keys are key-signing keys and transactions keys
are zone-signing keys, these recommendations will lead to rollovers are zone-signing keys, these recommendations will lead to rollovers
occurring frequently enough to become part of 'operational habits'; occurring frequently enough to become part of 'operational habits';
the procedure does not have to be reinvented every time a key is the procedure does not have to be reinvented every time a key is
replaced. replaced.
3.2.2 Key Algorithm 3.2.2 Key Algorithm
We recommend you choose RSA/SHA-1 as the preferred algorithm for the There are currently three different types of algorithms that can be
key. RSA has been developed in an open and transparent manner. As the used in DNSSEC: RSA, DSA and elliptic curve cryptography. The latter
patent on RSA expired in 2001, its use is now also free. The current is fairly new and still needs to be standardized for usage in DNSSEC.
known attacks on RSA can be defeated by making your key longer. As
the MD5 hashing algorithm is showing (theoretical) cracks, we RSA has been developed in an open and transparent manner. As the
recommend the usage of SHA1. patent on RSA expired in 2000, its use is now also free.
DSA has been developed by NIST. The creation of signatures creation
is roughly the same speed as with RSA, but is 10 to 40 times as slow
for verification [11].
We suggest the use of RSA/SHA-1 as the preferred algorithm for the
key. The current known attacks on RSA can be defeated by making your
key longer. As the MD5 hashing algorithm is showing (theoretical)
cracks, we recommend the usage of SHA1.
3.2.3 Key Sizes 3.2.3 Key Sizes
When choosing key sizes, zone administrators will need to take into When choosing key sizes, zone administrators will need to take into
account how long a key will be used and how much data will be signed account how long a key will be used and how much data will be signed
during the key publication period. It is hard to give precise during the key publication period. It is hard to give precise
recommendations but Lenstra and Verheul [9] supplied the following recommendations but Lenstra and Verheul [10] supplied the following
table with lower bound estimates for cryptographic key sizes. Their table with lower bound estimates for cryptographic key sizes. Their
recommendations are based on a set of explicitly formulated parameter recommendations are based on a set of explicitly formulated parameter
settings, combined with existing data points about cryptosystems. For settings, combined with existing data points about cryptographic
details we refer to the original paper. systems. For details we refer to the original paper.
[Editor's Note: DSA???]
Year RSA Key Sizes Elliptic Curve Key Size
2000 952 132
2001 990 135
2002 1028 139
2003 1068 140
2004 1108 143
2005 1149 147
2006 1191 148
2007 1235 152
2008 1279 155
2009 1323 157
2010 1369 160 Year RSA Key Sizes Year RSA Key Sizes
2011 1416 163
2012 1464 165
2013 1513 168
2014 1562 172
2015 1613 173 2000 952 2015 1613
2016 1664 177 2001 990 2016 1664
2017 1717 180 2002 1028 2017 1717
2018 1771 181 2003 1068 2018 1771
2019 1825 185 2004 1108 2019 1825
2020 1881 188 2005 1149 2020 1881
2021 1937 190 2006 1191 2021 1937
2022 1995 193 2007 1235 2022 1995
2023 2054 197 2008 1279 2023 2054
2024 2113 198 2009 1323 2024 2113
2025 2174 202 2026 2236 2025 2174
2026 2236 205 2010 1369 2027 2299
2027 2299 207 2011 1416 2028 2362
2028 2362 210 2012 1464 2029 2427
2029 2427 213 2013 1513
2014 1562
For example, should you wish your key to last three years from 2003, For example, should you wish your key to last three years from 2003,
check the RSA keysize values for 2006 in this table. In this case check the RSA keysize values for 2006 in this table. In this case
1191. 1191.
3.3 Key Rollovers 3.3 Key Rollovers
Key rollovers are a fact of life when using DNSSEC. A DNSSEC key A DNSSEC key cannot be used forever (see RFC2541 [2] and Section
cannot be used forever (see RFC2541 [2] and Section 3.2 ). Zone 3.2). So key rollovers are a fact of life when using DNSSEC. Zone
administrators who are in the process of rolling their keys have to administrators who are in the process of rolling their keys have to
take into account that data published in previous versions of their take into account that data published in previous versions of their
zone still lives in caches. When deploying DNSSEC, this becomes an zone still lives in caches. When deploying DNSSEC, this becomes an
important consideration; ignoring data that may be in caches may lead important consideration; ignoring data that may be in caches may lead
to loss of service for clients. to loss of service for clients.
The most pressing example of this is when zone material signed with The most pressing example of this is when zone material signed with
an old key is being validated by a resolver which does not have the an old key is being validated by a resolver which does not have the
old zone key cached. If the old key is no longer present in the old zone key cached. If the old key is no longer present in the
current zone, this validation fails, marking the data bogus. current zone, this validation fails, marking the data bogus.
Alternatively, an attempt could be made to validate data which is Alternatively, an attempt could be made to validate data which is
signed with a new key against an old key that lives in a local cache, signed with a new key against an old key that lives in a local cache,
also resulting in data being marked bogus. also resulting in data being marked bogus.
To appreciate the situation one could think of a number of 3.3.1 Difference Between ZSK and KSK Rollovers
authoritative servers that may not be instantaneously running the
same version of a zone and a security aware non-recursive resolver
that sits behind security aware caching forwarders.
Note that KSK rollovers and ZSK rollovers are different. A zone-key Note that KSK rollovers and ZSK rollovers are different. A zone-key
rollover can be handled in two different ways: pre-publish (Section rollover can be handled in two different ways: pre-publish (Section
Section 3.3.1.1) and double signature (Section Section 3.3.1.2). The Section 3.3.2.1) and double signature (Section Section 3.3.2.2).
pre-publish technique works because the key-signing key stays the
same during this ZSK rollover. With this KSK a cache is able to
validate the new keyset of a zone. With a KSK rollover a cache can
not validate the new keyset, because it does not trust the new KSK.
[Editors note: This needs more verbose explanation, nobody will As the KSK is used to validate the key set and because the KSK is not
appreciate the situation just yet. Help with text and examples is changed during a ZSK rollover, a cache is able to validate the new
appreciated] key set of the zone. The pre-publish method does not work for a KSK
rollover. The following example demonstrates that, here rollover the
KSK from DNSKEY1 to DNSKEY2 using the NONE working pre-publish
method.
3.3.1 Zone-signing Key Rollovers normal pre-roll roll after
SOA0 SOA1 SOA2 SOA3
RRSIG10(SOA0) RRSIG10(SOA1) RRSIG11(SOA2) RRSIG11(SOA3)
DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY2
DNSKEY10 DNSKEY2 DNSKEY2 DNSKEY10
DNSKEY10 DNSKEY10
RRSIG1 (DNSKEY) RRSIG1 (DNSKEY) RRSIG2(DNSKEY) RRSIG2 (DNSKEY)
RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY)
A cache that queries the zone during the "normal" step gets back
DNSKEY1. The DS RR and the key set are cached. If the TTL of the DS
RR is large enough, the DS RR remains in the cache until the "after"
step. If in this case, the key set TTL expires, and the cache
queries for the zone again, it will get back the new key set signed
by DNSKEY2. It will then try to validate the key set with DNSKEY1
and will fail.
3.3.2 Zone-signing Key Rollovers
For zone-signing key rollovers there are two ways to make sure that For zone-signing key rollovers there are two ways to make sure that
during the rollover data still cached can be verified with the new during the rollover data still cached can be verified with the new
keysets or newly generated signatures can be verified with the keys keysets or newly generated signatures can be verified with the keys
still in caches. One schema uses double signatures, it is described still in caches. One schema uses double signatures, it is described
in Section 3.3.1.2, the other uses key pre-publication (Section in Section 3.3.2.2, the other uses key pre-publication (Section
3.3.1.1). The pros, cons and recommendations are described in Section 3.3.2.1). The pros, cons and recommendations are described in
3.3.1.3. Section 3.3.2.3.
3.3.1.1 Pre-publish Keyset Rollover 3.3.2.1 Pre-publish key set Rollover
This section shows how to perform a ZSK rollover without the need to This section shows how to perform a ZSK rollover without the need to
sign all the data in a zone twice - the so called "prepublish sign all the data in a zone twice - the so called "pre-publish
rollover". We recommend this method because it has advantages in the rollover".This method has advantages in the case of a key compromise.
case of key compromise. If the old key is compromised, the new key If the old key is compromised, the new key has already been
has already been distributed in the DNS. The zone administrator is distributed in the DNS. The zone administrator is then able to
then able to quickly switch to the new key and remove the compromised quickly switch to the new key and remove the compromised key from the
key from the zone. Another major advantage is that the zone size does zone. Another major advantage is that the zone size does not double,
not double, as is the case with the double signature ZSK rollover. A as is the case with the double signature ZSK rollover. A small
small "HOWTO" for this kind of rollover can be found in Appendix B. "HOWTO" for this kind of rollover can be found in Appendix B.
normal pre-roll roll after normal pre-roll roll after
SOA0 SOA1 SOA2 SOA3 SOA0 SOA1 SOA2 SOA3
RRSIG10(SOA0) RRSIG10(SOA1) RRSIG11(SOA2) RRSIG11(SOA3) RRSIG10(SOA0) RRSIG10(SOA1) RRSIG11(SOA2) RRSIG11(SOA3)
DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1
DNSKEY10 DNSKEY10 DNSKEY10 DNSKEY11 DNSKEY10 DNSKEY10 DNSKEY10 DNSKEY11
DNSKEY11 DNSKEY11 DNSKEY11 DNSKEY11
RRSIG1 (DNSKEY) RRSIG1 (DNSKEY) RRSIG1(DNSKEY) RRSIG1 (DNSKEY) RRSIG1 (DNSKEY) RRSIG1 (DNSKEY) RRSIG1(DNSKEY) RRSIG1 (DNSKEY)
skipping to change at page 11, line 40 skipping to change at page 12, line 4
DNSKEY 10 are removed from the zone). DNSKEY 10 remains published DNSKEY 10 are removed from the zone). DNSKEY 10 remains published
in the keyset. This way data that was loaded into caches from in the keyset. This way data that was loaded into caches from
version 1 of the zone can still be verified with key sets fetched version 1 of the zone can still be verified with key sets fetched
from version 2 of the zone. from version 2 of the zone.
The minimum time that the keyset including DNSKEY 10 is to be The minimum time that the keyset including DNSKEY 10 is to be
published is the time that it takes for zone data from the published is the time that it takes for zone data from the
previous version of the zone to expire from old caches i.e. the previous version of the zone to expire from old caches i.e. the
time it takes for this zone to propagate to all authoritative time it takes for this zone to propagate to all authoritative
servers plus the Maximum Zone TTL value of any of the data in the servers plus the Maximum Zone TTL value of any of the data in the
previous version of the zone. previous version of the zone.
after: DNSKEY 10 is removed from the zone. The keyset, now only after: DNSKEY 10 is removed from the zone. The keyset, now only
containing DNSKEY 11 is resigned with the DNSKEY 1. containing DNSKEY 11 is resigned with the DNSKEY 1.
The above scheme can be simplified by always publishing the "future" The above scheme can be simplified by always publishing the "future"
key immediately after the rollover. The scheme would look as follows key immediately after the rollover. The scheme would look as follows
(we show two rollovers); the future key is introduced in "after" as (we show two rollovers); the future key is introduced in "after" as
DNSKEY 12 and again a newer one, numbered 13, in "2nd after": DNSKEY 12 and again a newer one, numbered 13, in "2nd after":
normal roll after 2nd roll 2nd after normal roll after
SOA0 SOA2 SOA3 SOA4 SOA5 SOA0 SOA2 SOA3
RRSIG10(SOA0) RRSIG11(SOA2) RRSIG11(SOA3) RRSIG12(SOA4) RRSIG12(SOA5) RRSIG10(SOA0) RRSIG11(SOA2) RRSIG11(SOA3)
DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1
DNSKEY10 DNSKEY10 DNSKEY11 DNSKEY11 DNSKEY12 DNSKEY10 DNSKEY10 DNSKEY11
DNSKEY11 DNSKEY11 DNSKEY12 DNSKEY12 DNSKEY13 DNSKEY11 DNSKEY11 DNSKEY12
RRSIG1(DNSKEY) RRSIG1 (DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1 (DNSKEY) RRSIG1(DNSKEY)
RRSIG10(DNSKEY) RRSIG11(DNSKEY) RRSIG11(DNSKEY) RRSIG12(DNSKEY) RRSIG12(DNSKEY) RRSIG10(DNSKEY) RRSIG11(DNSKEY) RRSIG11(DNSKEY)
2nd roll 2nd after
SOA4 SOA5
RRSIG12(SOA4) RRSIG12(SOA5)
DNSKEY1 DNSKEY1
DNSKEY11 DNSKEY12
DNSKEY12 DNSKEY13
RRSIG1(DNSKEY) RRSIG1(DNSKEY)
RRSIG12(DNSKEY) RRSIG12(DNSKEY)
Note that the key introduced after the rollover is not used for Note that the key introduced after the rollover is not used for
production yet; the private key can thus be stored in a physically production yet; the private key can thus be stored in a physically
secure manner and does not need to be 'fetched' every time a zone secure manner and does not need to be 'fetched' every time a zone
needs to be signed. needs to be signed.
This scheme has the benefit that the key that is intended for future 3.3.2.2 Double Signature Zone-signing Key Rollover
use: immediately during an emergency rollover assuming that the
private key was stored in a physically secure manner.
3.3.1.2 Double Signature Zone-signing Key Rollover
This section shows how to perform a ZSK key rollover using the double This section shows how to perform a ZSK key rollover using the double
zone data signature scheme, aptly named "double sig rollover". zone data signature scheme, aptly named "double sig rollover".
During the rollover stage the new version of the zone file will need During the rollover stage the new version of the zone file will need
to propagate to all authoritative servers and the data that exists in to propagate to all authoritative servers and the data that exists in
(distant) caches will need to expire, this will take at least the (distant) caches will need to expire, this will take at least the
maximum Zone TTL . maximum Zone TTL .
normal roll after normal roll after
skipping to change at page 13, line 4 skipping to change at page 13, line 21
DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1 DNSKEY1
DNSKEY10 DNSKEY10 DNSKEY11 DNSKEY10 DNSKEY10 DNSKEY11
DNSKEY11 DNSKEY11
RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY) RRSIG1(DNSKEY)
RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG11(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG11(DNSKEY)
RRSIG11(DNSKEY) RRSIG11(DNSKEY)
normal: Version 0 of the zone: DNSKEY 1 is the key-signing key. normal: Version 0 of the zone: DNSKEY 1 is the key-signing key.
DNSKEY 10 is used to sign all the data of the zone, the DNSKEY 10 is used to sign all the data of the zone, the
zone-signing key. zone-signing key.
roll: At the rollover stage (SOA serial 1) DNSKEY 11 is introduced roll: At the rollover stage (SOA serial 1) DNSKEY 11 is introduced
into the keyset and all the data in the zone is signed with DNSKEY into the key set and all the data in the zone is signed with
10 and DNSKEY 11. The rollover period will need to exist until all DNSKEY 10 and DNSKEY 11. The rollover period will need to exist
data from version 0 of the zone has expired from remote caches. until all data from version 0 of the zone has expired from remote
This will take at least the maximum Zone TTL of version 0 of the caches. This will take at least the maximum Zone TTL of version 0
zone. of the zone.
after: DNSKEY 10 is removed from the zone. All the signatures from after: DNSKEY 10 is removed from the zone. All the signatures from
DNSKEY 10 are removed from the zone. The keyset, now only DNSKEY 10 are removed from the zone. The keyset, now only
containing DNSKEY 11, is resigned with DNSKEY 1. containing DNSKEY 11, is resigned with DNSKEY 1.
At every instance the data from the previous version of the zone can At every instance the data from the previous version of the zone can
be verified with the key from the current version and vice verse. The be verified with the key from the current version and the other way
data from the current version can be verified with the data from the around. The data from the current version can be verified with the
previous version of the zone. The duration of the rollover phase and data from the previous version of the zone. The duration of the
the period between rollovers should be at least the "Maximum Zone rollover phase and the period between rollovers should be at least
TTL". the "Maximum Zone TTL".
Making sure that the rollover phase lasts until the signature Making sure that the rollover phase lasts until the signature
expiration time of the data in version 0 of the zone is recommended. expiration time of the data in version 0 of the zone is recommended.
However, this date could be considerably longer than the Maximum Zone This way all caches are cleared of the old signatures. However, this
TTL, making the rollover a lengthy procedure. date could be considerably longer than the Maximum Zone TTL, making
the rollover a lengthy procedure.
Note that in this example we assumed that the zone was not modified Note that in this example we assumed that the zone was not modified
during the rollover. New data can be introduced in the zone as long during the rollover. New data can be introduced in the zone as long
as it is signed with both keys. as it is signed with both keys.
3.3.1.3 Pros and Cons of the Schemes 3.3.2.3 Pros and Cons of the Schemes
Pre-publish-key set rollover: This rollover does not involve signing
Prepublish-keyset rollover: This rollover does not involve signing the zone data twice. Instead, just before the actual rollover,
the zone data twice. Instead, just before the actual rollover, the the new key is published in the key set and thus available for
new key is published in the keyset and thus available for cryptanalysis attacks. A small disadvantage is that this process
cryptanalysis attacks. A small disavantage is that this process requires four steps. Also the pre-publish scheme will not work
requires four steps. Also the prepublish scheme will not work for for KSKs as explained in Section 3.3.
KSKs as explained in Section 3.3.
Double signature rollover: The drawback of this signing scheme is Double signature rollover: The drawback of this signing scheme is
that during the rollover the number of signatures in your zone that during the rollover the number of signatures in your zone
doubles, this may be prohibitive if you have very big zones. An doubles, this may be prohibitive if you have very big zones. An
advantage is that it only requires three steps. advantage is that it only requires three steps.
3.3.2 Key-signing Key Rollovers 3.3.3 Key-signing Key Rollovers
For the rollover of a key-signing key the same considerations as for For the rollover of a key-signing key the same considerations as for
the rollover of a zone-signing key apply. However we can use a double the rollover of a zone-signing key apply. However we can use a
signature scheme to guarantee that old data (only the apex keyset) in double signature scheme to guarantee that old data (only the apex key
caches can be verified with a new keyset and vice versa. set) in caches can be verified with a new key set and vice versa.
Since only the keyset is signed with a KSK, zone size considerations Since only the keyset is signed with a KSK, zone size considerations
do not apply. do not apply.
normal roll after normal roll after
SOA0 SOA1 SOA2 SOA0 SOA1 SOA2
RRSIG10(SOA0) RRSIG10(SOA1) RRSIG10(SOA2) RRSIG10(SOA0) RRSIG10(SOA1) RRSIG10(SOA2)
DNSKEY1 DNSKEY1 DNSKEY2 DNSKEY1 DNSKEY1 DNSKEY2
skipping to change at page 14, line 24 skipping to change at page 14, line 44
RRSIG2 (DNSKEY) RRSIG2 (DNSKEY)
RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY) RRSIG10(DNSKEY)
normal: Version 0 of the zone. The parental DS points to DNSKEY1. normal: Version 0 of the zone. The parental DS points to DNSKEY1.
Before the rollover starts the child will have to verify what the Before the rollover starts the child will have to verify what the
TTL is of the DS RR that points to DNSKEY1 - it is needed during TTL is of the DS RR that points to DNSKEY1 - it is needed during
the rollover and we refer to the value as TTL_DS. the rollover and we refer to the value as TTL_DS.
roll: During the rollover phase the zone administrator generates a roll: During the rollover phase the zone administrator generates a
second KSK, DNSKEY2. The key is provided to the parent and the second KSK, DNSKEY2. The key is provided to the parent and the
child will have to wait until a new DS RR has been generated that child will have to wait until a new DS RR has been generated that
points to DNSKEY2. After that DS RR has been published on _all_ points to DNSKEY2. After that DS RR has been published on all
servers authoritative for the parents zone, the zone administrator servers authoritative for the parents zone, the zone administrator
has to wait at least TTL_DS to make sure that the old DS RR has has to wait at least TTL_DS to make sure that the old DS RR has
expired from distant caches. expired from caches.
after: DNSKEY1 has been removed. after: DNSKEY1 has been removed.
The scenario above puts the responsibility for maintaining a valid The scenario above puts the responsibility for maintaining a valid
chain of trust with the child. It also is based on the premises that chain of trust with the child. It also is based on the premises hat
the parent only has one DS RR (per algorithm) per zone. St John [The the parent only has one DS RR (per algorithm) per zone. An
draft has expired] proposed a mechanism where using an established alternative mechanism has been considered. Using an established
trust relation, the interaction can be performed in-band. In this trust relation, the interaction can be performed in-band, and where
mechanism there are periods where there are two DS RRs at the parent. removal of the keys by the child can be signaled by the parent. In
this mechanism there are periods where there are two DS RRs at the
parent. Since at the moment of writing the protocol for this
interaction has not been developed further discussion is out of scope
for this document.
[Editors note: We probably need to mention more] 3.3.4 Automated Key Rollovers
As keys must be renewed periodically, there are some motivation to
automate the rollover process (also see [12])
o ZSK rollovers are easy to automate as only the local zone is
involved.
o A KSK rollover needs interaction between the parent and child.
Data exchange is needed to provide the new keys to the parent,
consequently, this data must be authenticated and integrity must
be guaranteed in order to avoid attacks on the rollover.
o All time and TTL considerations presented in Section 3.3 apply to
an automated rollover.
4. Planning for Emergency Key Rollover 4. Planning for Emergency Key Rollover
This section deals with preparation for a possible key compromise. This section deals with preparation for a possible key compromise.
Our advice is to have a documented procedure ready for when a key Our advice is to have a documented procedure ready for when a key
compromise is suspected or confirmed. compromise is suspected or confirmed.
[Editors note: We are much in favor of a rollover tactic that keeps
the authentication chain intact as long as possible. This means that
one has to take all the regular rollover properties into account.]
When the private material of one of your keys is compromised it can When the private material of one of your keys is compromised it can
be used for as long as a valid authentication chain exists. An be used for as long as a valid authentication chain exists. An
authentication chain remains intact for: authentication chain remains intact for:
o as long as a signature over the compromised key in the o as long as a signature over the compromised key in the
authentication chain is valid, authentication chain is valid,
o as long as a parental DS RR (and signature) points to the o as long as a parental DS RR (and signature) points to the
compromised key, compromised key,
o as long as the key is anchored in a resolver and is used as a o as long as the key is anchored in a resolver and is used as a
starting point for validation. (This is the hardest to update.) starting point for validation. (This is the hardest to update.)
While an authentication chain to your compromised key exists, your While an authentication chain to your compromised key exists, your
name-space is vulnerable to abuse by the malicious key holder (i.e. name-space is vulnerable to abuse by the malicious key holder (i.e.
the owner of the compromised key). Zone operators have to make a the owner of the compromised key). Zone operators have to make a
trade off if the abuse of the compromised key is worse than having trade off if the abuse of the compromised key is worse than having
data in caches that cannot be validated. If the zone operator chooses data in caches that cannot be validated. If the zone operator
to break the authentication chain to the compromised key, data in chooses to break the authentication chain to the compromised key,
caches signed with this key cannot be validated. However, if the zone data in caches signed with this key cannot be validated. However, if
administrator chooses to take the path of a regular roll-over, the the zone administrator chooses to take the path of a regular
malicious key holder can spoof data so that it appears to be valid, roll-over, the malicious key holder can spoof data so that it appears
note that this kind of attack will usually be localised in the to be valid. Note that this kind of attack is more likely to occur
Internet topology. in a localized part of the network topology i.e. downstream from
where the spoof takes place.
4.1 KSK Compromise 4.1 KSK Compromise
When the KSK has been compromised the parent must be notified as soon When the KSK has been compromised the parent must be notified as soon
as possible using secure means. The keyset of the zone should be as possible using secure means. The keyset of the zone should be
resigned as soon as possible. Care must be taken to not break the resigned as soon as possible. Care must be taken to not break the
authentication chain. The local zone can only be resigned with the authentication chain. The local zone can only be resigned with the
new KSK after the parent's zone has been updated with the new KSK. new KSK after the parent's zone has created and reloaded its zone
Before this update takes place it would be best to drop the security with the DS created from the new KSK. Before this update takes place
status of a zone all together: the parent removes the DS of the child it would be best to drop the security status of a zone all together:
at the next zone update. After that the child can be made secure the parent removes the DS of the child at the next zone update.
again. After that the child can be made secure again.
An additional danger of a key compromise is that the compromised key An additional danger of a key compromise is that the compromised key
can be used to facilitate a legitimate DNSKEY/DS and/or nameserver can be used to facilitate a legitimate DNSKEY/DS and/or nameserver
rollover at the parent. When that happens the domain can be in rollover at the parent. When that happens the domain can be in
dispute. An out of band and secure notify mechanism to contact a dispute. An out of band and secure notify mechanism to contact a
parent is needed in this case. parent is needed in this case.
4.2 ZSK Compromise 4.2 ZSK Compromise
Primarily because there is no parental interaction required when a Primarily because there is no parental interaction required when a
ZSK is compromised, the situation is less severe than with with a KSK ZSK is compromised, the situation is less severe than with with a KSK
compromise. The zone must still be resigned with a new ZSK as soon compromise. The zone must still be resigned with a new ZSK as soon
as possible. As this is a local operation and requires no as possible. As this is a local operation and requires no
communication between the parent and child this can be achieved communication between the parent and child this can be achieved
fairly quickly. However, one has to take into account that just as fairly quickly. However, one has to take into account that just as
with a normal rollover the immediate disappearance from the old with a normal rollover the immediate disappearance from the old
compromised key may lead to verification problems. The compromised key may lead to verification problems. The
pre-publication scheme as discussed above minimises such problems. pre-publication scheme as discussed above minimizes such problems.
4.3 Compromises of Keys Anchored in Resolvers 4.3 Compromises of Keys Anchored in Resolvers
A key can also be pre-configured in resolvers. If DNSSEC is rolled A key can also be pre-configured in resolvers. For instance, if
out as planned the root key should be pre-configured in every secure DNSSEC is successfully deployed the root key will be pre-configured
aware resolver on the planet. [Editors Note: add more about in most security aware resolvers.
authentication of a newly received resolver key]
If trust-anchor keys are compromised, the resolvers using these keys If trust-anchor keys are compromised, the resolvers using these keys
should be notified of this fact. Zone administrators may consider should be notified of this fact. Zone administrators may consider
setting up a mailing list to communicate the fact that a SEP key is setting up a mailing list to communicate the fact that a SEP key is
about to be rolled over. This communication will of course need to be about to be rolled over. This communication will of course need to
authenticated e.g. by using digital signatures. be authenticated e.g. by using digital signatures.
End-user faced with the task of updating anchored key should always
validate the new key. New keys should be authenticated out of the
DNS, for example, looking them up on an x.509 secured announcement
website.
5. Parental Policies 5. Parental Policies
5.1 Initial Key Exchanges and Parental Policies Considerations 5.1 Initial Key Exchanges and Parental Policies Considerations
The initial key exchange is always subject to the policies set by the The initial key exchange is always subject to the policies set by the
parent (or its registry). When designing a key exchange policy one parent (or its registry). When designing a key exchange policy one
should take into account that the authentication and authorisation should take into account that the authentication and authorization
mechanisms used during a key exchange should be as strong as the mechanisms used during a key exchange should be as strong as the
authentication and authorisation mechanisms used for the exchange of authentication and authorization mechanisms used for the exchange of
delegation information between parent and child. delegation information between parent and child. I.e. there is no
implicit need in DNSSEC to make the authentication process stronger
than it was in DNS.
Using the DNS itself as the source for the actual DNSKEY material, Using the DNS itself as the source for the actual DNSKEY material,
with an off-band check on the validity of the DNSKEY, has the benefit with an off-band check on the validity of the DNSKEY, has the benefit
that it reduces the chances of user error. A parental DNSKEY download that it reduces the chances of user error. A parental DNSKEY
tool can make use of the SEP bit [4] to select the proper key from a download tool can make use of the SEP bit [4] to select the proper
DNSSEC keyset; thereby reducing the chance that the wrong DNSKEY is key from a DNSSEC key set; thereby reducing the chance that the wrong
sent. It can validate the self-signature over a key; thereby DNSKEY is sent. It can validate the self-signature over a key;
verifying the ownership of the private key material. Fetching the thereby verifying the ownership of the private key material.
DNSKEY from the DNS ensures that the child will not become bogus once Fetching the DNSKEY from the DNS ensures that the child will not
the parent publishes the DS RR indicating the child is secure. become bogus once the parent publishes the DS RR indicating the child
is secure.
Note: the off-band verification is still needed when the key-material Note: the off-band verification is still needed when the key-material
is fetched by a tool. The parent can not be sure whether the DNSKEY is fetched via the DNS. The parent can never be sure whether the
RRs have been spoofed. DNSKEY RRs have been spoofed or not.
5.2 Storing Keys So Hashes Can Be Regenerated 5.2 Storing Keys So Hashes Can Be Regenerated
When designing a registry system one should consider if the DNSKEYs When designing a registry system one should consider if the DNSKEYs
and/or the corresponding DSs are stored. Storing DNSKEYs will help and/or the corresponding DSs are stored. Storing DNSKEYs will help
during troubleshooting while the overhead of calculating DS records during troubleshooting while the overhead of calculating DS records
from them is minimal. from them is minimal.
Having an out-of-band mechanism, such as a Whois database, to find Having an out-of-band mechanism, such as a Whois database, to find
out which keys are used to generate DS Resource Records for specific out which keys are used to generate DS Resource Records for specific
owners may also help with troubleshooting. owners and/or zones may also help with troubleshooting.
5.3 Security Lameness Checks 5.3 Security Lameness Checks
Security Lameness is defined as what happens when a parent has a DS Security Lameness is defined as what happens when a parent has a DS
Resource Record pointing to a non-existing DNSKEY RR. During key RR pointing to a non-existing DNSKEY RR. During key exchange a
exchange a parent should make sure that the child's key is actually parent should make sure that the child's key is actually configured
configured in the DNS before publishing a DS RR in its zone. Failure in the DNS before publishing a DS RR in its zone. Failure to do so
to do so would render the child's zone being marked as bogus. would render the child's zone being marked as bogus.
Child zones should be very careful removing DNSKEY material, Child zones should be very careful removing DNSKEY material,
specifically SEP keys, for which a DS RR exists. specifically SEP keys, for which a DS RR exists.
Once a zone is "security lame" a fix (e.g. by removing a DS RR) will Once a zone is "security lame" a fix (e.g. by removing a DS RR) will
take time to propagate through the DNS. take time to propagate through the DNS.
5.4 DS Signature Validity Period 5.4 DS Signature Validity Period
Since the DS can be replayed as long as it has a valid signature a Since the DS can be replayed as long as it has a valid signature a
short signature validity period over the DS minimises the time a short signature validity period over the DS minimizes the time a
child is vulnerable in the case of a compromise of the child's child is vulnerable in the case of a compromise of the child's
KSK(s). A signature validity period that is too short introduces the KSK(s). A signature validity period that is too short introduces the
possibility that a zone is marked bogus in case of a configuration possibility that a zone is marked bogus in case of a configuration
error in the signer; there may not be enough time to fix the problems error in the signer. There may not be enough time to fix the
before signatures expire. Something as mundane as operator problems before signatures expire. Something as mundane as operator
unavailability during weekends shows the need for DS signature unavailability during weekends shows the need for DS signature
lifetimes longer than 2 days. We recommend the minimum for a DS lifetimes longer than 2 days. We recommend the minimum for a DS
signature validity period to be a few days. signature validity period to be a few days.
The maximum signature lifetime of the DS record depends on how long The maximum signature lifetime of the DS record depends on how long
child zones are willing to be vulnerable after a key compromise. We child zones are willing to be vulnerable after a key compromise.
consider a signature validity period of around one week to be a good Other considerations, such as how often the zone is (re)signed can
compromise between the operational constraints of the parent and also be taken into account.
minimising damage for the child.
We consider a signature validity period of around one week to be a
good compromise between the operational constraints of the parent and
minimizing damage for the child.
6. Security Considerations 6. Security Considerations
DNSSEC adds data integrity to the DNS. This document tries to assess DNSSEC adds data integrity to the DNS. This document tries to assess
considerations to operate a stable and secure DNSSEC service. Not considerations to operate a stable and secure DNSSEC service. Not
taking into account the 'data propagation' properties in the DNS will taking into account the 'data propagation' properties in the DNS will
cause validation failures and may make secured zones unavailable to cause validation failures and may make secured zones unavailable to
security aware resolvers. security aware resolvers.
7. Acknowledgments 7. Acknowledgments
We, the folk mentioned as authors, only acted as editors. Most of the We, the folk mentioned as authors, only acted as editors. Most of
ideas in this draft were the result of collective efforts during the ideas in this draft were the result of collective efforts during
workshops, discussions and try outs. workshops, discussions and try outs.
At the risk of forgetting individuals who where the original At the risk of forgetting individuals who where the original
contributors of the ideas we would like to acknowledge people who contributors of the ideas we would like to acknowledge people who
where actively involved in the compilation of this document. In where actively involved in the compilation of this document. In
random order: Olafur Gudmundsson, Wesley Griffin, Michael Richardson, random order: Olafur Gudmundsson, Wesley Griffin, Michael Richardson,
Scott Rose, Rick van Rein, Tim McGinnis, Gilles Guette and Olivier Scott Rose, Rick van Rein, Tim McGinnis, Gilles Guette and Olivier
Courtay, Sam Weiler. Courtay, Sam Weiler, Jelte Jansen.
Mike StJohns designed the key exchange between parent and child
mentioned in the last paragraph of Section 3.3.3
Section 3.3.4 was supplied by G. Guette and O. Courtay.
Emma Bretherick and Adrian Bedford corrected many of the spelling and Emma Bretherick and Adrian Bedford corrected many of the spelling and
style issues. style issues.
Kolkman and Gieben take the blame for introducing all miscakes(SIC). Kolkman and Gieben take the blame for introducing all miscakes(SIC).
8. References 8. References
8.1 Normative References 8.1 Normative References
skipping to change at page 18, line 32 skipping to change at page 19, line 40
[2] Eastlake, D., "DNS Security Operational Considerations", RFC [2] Eastlake, D., "DNS Security Operational Considerations", RFC
2541, March 1999. 2541, March 1999.
[3] Lewis, E., "DNS Security Extension Clarification on Zone [3] Lewis, E., "DNS Security Extension Clarification on Zone
Status", RFC 3090, March 2001. Status", RFC 3090, March 2001.
[4] Lewis, E., Kolkman, O. and J. Schlyter, "KEY RR Key-Signing Key [4] Lewis, E., Kolkman, O. and J. Schlyter, "KEY RR Key-Signing Key
(KSK) Flag", draft-ietf-dnsext-keyrr-key-signing-flag-06 (work (KSK) Flag", draft-ietf-dnsext-keyrr-key-signing-flag-06 (work
in progress), February 2003. in progress), February 2003.
[5] Arends, R., "DNS Security Introduction and Requirements",
draft-ietf-dnsext-dnssec-intro-11 (work in progress), March
2003.
[6] Arends, R., "Protocol Modifications for the DNS Security
Extensions", draft-ietf-dnsext-dnssec-protocol-07 (work in
progress), March 2003.
8.2 Informative References 8.2 Informative References
[5] Bradner, S., "Key words for use in RFCs to Indicate Requirement [7] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[6] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)", RFC [8] Andrews, M., "Negative Caching of DNS Queries (DNS NCACHE)",
2308, March 1998. RFC 2308, March 1998.
[7] Gudmundsson, O., "Delegation Signer Resource Record", [9] Gudmundsson, O., "Delegation Signer (DS) Resource Record (RR)",
draft-ietf-dnsext-delegation-signer-13 (work in progress), March RFC 3658, December 2003.
2003.
[8] Arends, R., "Protocol Modifications for the DNS Security [10] Lenstra, A. and E. Verheul, "Selecting Cryptographic Key
Extensions", draft-ietf-dnsext-dnssec-protocol-01 (work in Sizes", The Journal of Cryptology 14 (255-293), 2001.
progress), March 2003.
[9] Lenstra, A. and E. Verheul, "Selecting Cryptographic Key Sizes", [11] Schneier, B., "Applied Cryptography: Protocols, Algorithms, and
The Journal of Cryptology 14 (255-293), 2001. Source Code in C", 1996.
[12] Guette, G., "Requirements for Automated Key Rollover in
DNSsec", draft-ietf-dnsop-key-rollover-requirements-01 (work in
progress), August 2004.
Authors' Addresses Authors' Addresses
Olaf M. Kolkman Olaf M. Kolkman
RIPE NCC RIPE NCC
Singel 256 Singel 256
Amsterdam 1016 AB Amsterdam 1016 AB
The Netherlands The Netherlands
Phone: +31 20 535 4444 Phone: +31 20 535 4444
skipping to change at page 19, line 38 skipping to change at page 21, line 9
In this document there is some jargon used that is defined in other In this document there is some jargon used that is defined in other
documents. In most cases we have not copied the text from the documents. In most cases we have not copied the text from the
documents defining the terms but given a more elaborate explanation documents defining the terms but given a more elaborate explanation
of the meaning. Note that these explanations should not be seen as of the meaning. Note that these explanations should not be seen as
authoritative. authoritative.
Private and Public Keys: DNSSEC secures the DNS through the use of Private and Public Keys: DNSSEC secures the DNS through the use of
public key cryptography. Public key cryptography is based on the public key cryptography. Public key cryptography is based on the
existence of two keys, a public key and a private key. The public existence of two keys, a public key and a private key. The public
keys are published in the DNS by use of the DNSKEY Resource Record keys are published in the DNS by use of the DNSKEY Resource Record
(DNSKEY RR). Private keys should remain private i.e. should not be (DNSKEY RR). Private keys should remain private.
exposed to parties not-authorised to do the actual signing.
Signer: The system that has access to the private key material and Signer: The system that has access to the private key material and
signs the Resource Record sets in a zone. A signer may be signs the Resource Record sets in a zone. A signer may be
configured to sign only parts of the zone e.g. only those RRsets configured to sign only parts of the zone e.g. only those RRsets
for which existing signatures are about to expire. for which existing signatures are about to expire.
KSK: A Key-Signing Key (KSK) is a key that is used exclusively for KSK: A Key-Signing Key (KSK) is a key that is used exclusively for
signing the apex keyset. The fact that a key is a KSK is only signing the apex keyset. The fact that a key is a KSK is only
relevant to the signing tool. relevant to the signing tool.
ZSK: A Zone Signing Key (ZSK) is a key that is used for signing all ZSK: A Zone Signing Key (ZSK) is a key that is used for signing all
data in a zone. The fact that a key is a ZSK is only relevant to data in a zone. The fact that a key is a ZSK is only relevant to
the signing tool. the signing tool.
skipping to change at page 20, line 4 skipping to change at page 21, line 20
Signer: The system that has access to the private key material and Signer: The system that has access to the private key material and
signs the Resource Record sets in a zone. A signer may be signs the Resource Record sets in a zone. A signer may be
configured to sign only parts of the zone e.g. only those RRsets configured to sign only parts of the zone e.g. only those RRsets
for which existing signatures are about to expire. for which existing signatures are about to expire.
KSK: A Key-Signing Key (KSK) is a key that is used exclusively for KSK: A Key-Signing Key (KSK) is a key that is used exclusively for
signing the apex keyset. The fact that a key is a KSK is only signing the apex keyset. The fact that a key is a KSK is only
relevant to the signing tool. relevant to the signing tool.
ZSK: A Zone Signing Key (ZSK) is a key that is used for signing all ZSK: A Zone Signing Key (ZSK) is a key that is used for signing all
data in a zone. The fact that a key is a ZSK is only relevant to data in a zone. The fact that a key is a ZSK is only relevant to
the signing tool. the signing tool.
SEP Key: A KSK that has a parental DS record pointing to it. Note: SEP Key: A KSK that has a parental DS record pointing to it. Note:
this is not enforced in the protocol. A SEP Key with no parental this is not enforced in the protocol. A SEP Key with no parental
DS is security lame. DS is security lame.
Anchored Key: A DNSKEY configured in resolvers around the globe. This Anchored Key: A DNSKEY configured in resolvers around the globe.
Key is hard to update, hence the term anchored. This key is hard to update, hence the term anchored.
Bogus: [Editors Note: a reference here] An RRset in DNSSEC is marked Bogus: Also see Section 5 of [5]. An RRset in DNSSEC is marked
"Bogus" when a signature of a RRset does not validate against the "Bogus" when a signature of a RRset does not validate against a
DNSKEY. Even if the key itself was not marked Bogus. A cache may DNSKEY.
choose to cache Bogus data for various reasons.
Singing the Zone File: The term used for the event where an Singing the Zone File: The term used for the event where an
administrator joyfully signs its zone file while producing melodic administrator joyfully signs its zone file while producing melodic
sound patterns. sound patterns.
Zone Administrator: The 'role' that is responsible for signing a zone Zone Administrator: The 'role' that is responsible for signing a zone
and publishing it on the primary authoritative server. and publishing it on the primary authoritative server.
Appendix B. Zone-signing Key Rollover Howto Appendix B. Zone-signing Key Rollover Howto
Using the pre-published signature scheme and the most conservative Using the pre-published signature scheme and the most conservative
method to assure oneself that data does not live in distant caches method to assure oneself that data does not live in caches here
here follows the "HOWTO". [WES: has some comments about this] follows the "HOWTO".
Key notation: Key notation:
Step 0: The preparation: Create two keys and publish both in your Step 0: The preparation: Create two keys and publish both in your key
keyset. Mark one of the keys as "active" and the other as set. Mark one of the keys as "active" and the other as
"published". Use the "active" key for signing your zone data. "published". Use the "active" key for signing your zone data.
Store the private part of the "published" key, preferably Store the private part of the "published" key, preferably
off-line. off-line.
Step 1: Determine expiration: At the beginning of the rollover make a Step 1: Determine expiration: At the beginning of the rollover make a
note of the highest expiration time of signatures in your zone note of the highest expiration time of signatures in your zone
file created with the current key marked as "active". file created with the current key marked as "active".
Wait until the expiration time marked in Step 1 has passed Wait until the expiration time marked in Step 1 has passed
Step 2: Then start using the key that was marked as "published" to Step 2: Then start using the key that was marked as "published" to
sign your data i.e. mark it as "active". Stop using the key that sign your data i.e. mark it as "active". Stop using the key that
was marked as "active", mark it as "rolled". was marked as "active", mark it as "rolled".
skipping to change at page 20, line 48 skipping to change at page 22, line 15
Step 3: It is safe to engage in a new rollover (Step 1) after at Step 3: It is safe to engage in a new rollover (Step 1) after at
least one "signature validity period". least one "signature validity period".
Appendix C. Typographic Conventions Appendix C. Typographic Conventions
The following typographic conventions are used in this document: The following typographic conventions are used in this document:
Key notation: A key is denoted by KEYx, where x is a number, x could Key notation: A key is denoted by KEYx, where x is a number, x could
be thought of as the key id. be thought of as the key id.
RRset notations: RRs are only denoted by the type. All other RRset notations: RRs are only denoted by the type. All other
information - owner, class, rdata and TTL - is left out. Thus: information - owner, class, rdata and TTL - is left out. Thus:
example.com 3600 IN A 192.168.1.1 is reduced to: A. RRsets are a "example.com 3600 IN A 192.168.1.1" is reduced to "A". RRsets are
list of RRs. A example of this would be: A1,A2, specifying the a list of RRs. A example of this would be: "A1,A2", specifying
RRset containing two A records. This could again be abbreviated to the RRset containing two "A" records. This could again be
just: A. abbreviated to just "A".
Signature notation: Signatures are denoted as RRSIGx(RRset), which Signature notation: Signatures are denoted as RRSIGx(RRset), which
means that RRset is signed with DNSKEYx. means that RRset is signed with DNSKEYx.
Zone representation: Using the above notation we have simplified the Zone representation: Using the above notation we have simplified the
representation of a signed zone by leaving out all unnecessary representation of a signed zone by leaving out all unnecessary
details such as the names and by representing all data by "SOAx" details such as the names and by representing all data by "SOAx"
SOA representation: SOA's are represented as SOAx, where x is the SOA representation: SOA's are represented as SOAx, where x is the
serial number. serial number.
Using this notation the following zone : Using this notation the following zone :
example.net. 600 IN SOA ns.example.net. ernie.example.net. ( example.net. 600 IN SOA ns.example.net. bert.example.net. (
10 ; serial 10 ; serial
450 ; refresh (7 minutes 30 seconds) 450 ; refresh (7 minutes 30 seconds)
600 ; retry (10 minutes) 600 ; retry (10 minutes)
345600 ; expire (4 days) 345600 ; expire (4 days)
300 ; minimum (5 minutes) 300 ; minimum (5 minutes)
) )
600 RRSIG SOA 5 2 600 20130522213204 ( 600 RRSIG SOA 5 2 600 20130522213204 (
20130422213204 14 example.net. 20130422213204 14 example.net.
cmL62SI6iAX46xGNQAdQ... ) cmL62SI6iAX46xGNQAdQ... )
600 NS a.iana-servers.net. 600 NS a.iana-servers.net.
skipping to change at page 21, line 41 skipping to change at page 23, line 7
) ; key id = 14 ) ; key id = 14
3600 DNSKEY 256 3 5 ( 3600 DNSKEY 256 3 5 (
gsPW/Yy19GzYIY+Gnr8HABU... gsPW/Yy19GzYIY+Gnr8HABU...
) ; key id = 15 ) ; key id = 15
3600 RRSIG DNSKEY 5 2 3600 20130522213204 ( 3600 RRSIG DNSKEY 5 2 3600 20130522213204 (
20130422213204 14 example.net. 20130422213204 14 example.net.
J4zCe8QX4tXVGjV4e1r9... ) J4zCe8QX4tXVGjV4e1r9... )
3600 RRSIG DNSKEY 5 2 3600 20130522213204 ( 3600 RRSIG DNSKEY 5 2 3600 20130522213204 (
20130422213204 15 example.net. 20130422213204 15 example.net.
keVDCOpsSeDReyV6O... ) keVDCOpsSeDReyV6O... )
600 NSEC a.example.net. NS SOA TXT RRSIG DNSKEY NSEC
600 RRSIG NSEC 5 2 600 20130507213204 ( 600 RRSIG NSEC 5 2 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
obj3HEp1GjnmhRjX... ) obj3HEp1GjnmhRjX... )
a.example.net. 600 IN TXT "A label" a.example.net. 600 IN TXT "A label"
600 RRSIG TXT 5 3 600 20130507213204 ( 600 RRSIG TXT 5 3 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
IkDMlRdYLmXH7QJnuF3v... ) IkDMlRdYLmXH7QJnuF3v... )
600 NSEC b.example.com. TXT RRSIG NSEC 600 NSEC b.example.com. TXT RRSIG NSEC
600 RRSIG NSEC 5 3 600 20130507213204 ( 600 RRSIG NSEC 5 3 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
skipping to change at page 22, line 4 skipping to change at page 23, line 17
600 RRSIG NSEC 5 2 600 20130507213204 ( 600 RRSIG NSEC 5 2 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
obj3HEp1GjnmhRjX... ) obj3HEp1GjnmhRjX... )
a.example.net. 600 IN TXT "A label" a.example.net. 600 IN TXT "A label"
600 RRSIG TXT 5 3 600 20130507213204 ( 600 RRSIG TXT 5 3 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
IkDMlRdYLmXH7QJnuF3v... ) IkDMlRdYLmXH7QJnuF3v... )
600 NSEC b.example.com. TXT RRSIG NSEC 600 NSEC b.example.com. TXT RRSIG NSEC
600 RRSIG NSEC 5 3 600 20130507213204 ( 600 RRSIG NSEC 5 3 600 20130507213204 (
20130407213204 14 example.net. 20130407213204 14 example.net.
bZMjoZ3bHjnEz0nIsPMM... ) bZMjoZ3bHjnEz0nIsPMM... )
... ...
is reduced to the following represenation: is reduced to the following representation:
SOA10 SOA10
RRSIG14(SOA10) RRSIG14(SOA10)
DNSKEY14 DNSKEY14
DNSKEY15 DNSKEY15
RRSIG14(KEY) RRSIG14(KEY)
RRSIG15(KEY) RRSIG15(KEY)
The rest of the zone data has the same signature as the SOA record, The rest of the zone data has the same signature as the SOA record,
i.e a RRSIG created with DNSKEY 14. i.e a RRSIG created with DNSKEY 14.
Appendix D. Document Details and Changes Appendix D. Document Details and Changes
This section is to be removed by the RFC editor if and when the This section is to be removed by the RFC editor if and when the
document is published. document is published.
$Header: /var/cvs/dnssec-key/ $Id: draft-ietf-dnsop-dnssec-operational-practices.xml,v 1.29 2004/
draft-ietf-dnsop-dnssec-operational-practices.xml,v 1.22 2004/05/12 10/11 11:27:10 dnssec Exp $
08:29:11 dnssec Exp $
D.1 draft-ietf-dnsop-dnssec-operational-practices-00 D.1 draft-ietf-dnsop-dnssec-operational-practices-00
Submission as working group document. This document is a modified and Submission as working group document. This document is a modified
updated version of draft-kolkman-dnssec-operational-practices-00. and updated version of draft-kolkman-dnssec-operational-practices-00.
D.2 draft-ietf-dnsop-dnssec-operational-practices-01 D.2 draft-ietf-dnsop-dnssec-operational-practices-01
changed the definition of "Bogus" to reflect the one in the protocol changed the definition of "Bogus" to reflect the one in the protocol
draft. draft.
Bad to Bogus Bad to Bogus
Style and spelling corrections Style and spelling corrections
KSK - SEP mapping made explicit. KSK - SEP mapping made explicit.
Updates from Sam Weiler added Updates from Sam Weiler added
Intellectual Property Statement Intellectual Property Statement
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intellectual property or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
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standards-related documentation can be found in BCP-11. Copies of found in BCP 78 and BCP 79.
claims of rights made available for publication and any assurances of
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