RFC 4956
DNS Security (DNSSEC) Opt-In
RFC 4956: DNS Security (DNSSEC) Opt-In ✨
okay bestie, this is RFC 4956 🦋, the DNS Security (DNSSEC) Opt-In doc. The authors are R. Arends from Nominet, plus M. Kosters and D. Blacka from VeriSign, Inc. It's dated July 2007, and the category is Experimental 🧪, so this is a test run and not a standard. The title block doesn't list anything it obsoletes or updates, so it's just vibing on its own 💅
Status of This Memo ✨
This memo defines an Experimental Protocol for the Internet community. It is not an Internet standard of any kind 🙈 Discussion and suggestions for improvement are requested, so go wild. Distribution of this memo is unlimited.
Copyright Notice 📜
Copyright (C) The IETF Trust (2007).
Abstract 🌸
In the DNS security (DNSSEC) extensions, delegations to unsigned subzones are cryptographically secured. Keeping up that cryptography isn't always practical or necessary, honestly 😭 This document describes an experimental "Opt-In" model. It lets administrators skip that cryptography and cut the cost of adopting DNSSEC with large zones. It's giving budget-friendly, but make it secure 💜
Table of Contents 📑
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions and Terminology . . . . . . . . . . . . . . . . . 3
3. Experimental Status . . . . . . . . . . . . . . . . . . . . . 4
4. Protocol Additions . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Server Considerations . . . . . . . . . . . . . . . . . . 6
4.1.1. Delegations Only . . . . . . . . . . . . . . . . . . . 6
4.1.2. Insecure Delegation Responses . . . . . . . . . . . . 6
4.1.3. Dynamic Update . . . . . . . . . . . . . . . . . . . . 6
4.2. Client Considerations . . . . . . . . . . . . . . . . . . 7
4.2.1. Delegations Only . . . . . . . . . . . . . . . . . . . 7
4.2.2. Validation Process Changes . . . . . . . . . . . . . . 7
4.2.3. NSEC Record Caching . . . . . . . . . . . . . . . . . 8
4.2.4. Use of the AD bit . . . . . . . . . . . . . . . . . . 8
5. Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Transition Issues . . . . . . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . . 13
Appendix A. Implementing Opt-In Using "Views" . . . . . . . . . . 151. Overview 🎀
okay so the cost of cryptographically securing delegations to unsigned zones is high 😩 This is especially true for big delegation-centric zones and for zones where insecure delegations get updated a lot. For those zones, keeping up the NextSECure (NSEC) record chain can be extremely expensive compared to what you gain by cryptographically proving that unsecured zones exist.
This document describes an experimental way to get rid of the extra cryptography that shows up in secure delegations to unsigned zones 🦋 With "Opt-In", a zone admin can choose to take insecure delegations off the NSEC chain. The trick is extending what the NSEC record means by using a redundant bit in the type map. Iconic engineering, no cap ✨
2. Definitions and Terminology 📖
Throughout this document, you need to be familiar with the DNS system (RFC 1035 [1]), the DNS security extensions ([4], [5], and [6], referred to in this document as "standard DNSSEC"), and DNSSEC terminology (RFC 3090 [10]). It's assumed you already know this stuff, so no pressure 🙈
Here are the abbreviations and terms used in this document:
RR: a DNS resource record.
RRset: a Resource Record Set, as defined by [8]. In this document, the RRset also includes the covering RRSIG records, if any exist.
signed name: a DNS name that has, at minimum, a (signed) NSEC record.
unsigned name: a DNS name that does not (at least) have an NSEC record.
covering NSEC record/RRset: the NSEC record used to prove the (non)existence of a particular name or RRset. So for an RRset or name 'N', the covering NSEC record either has the name 'N', or has an owner name less than 'N' and a "next" name greater than 'N'. Main character energy 👑
delegation: an NS RRset with a name that's different from the current zone apex (non-zone-apex), meaning a delegation to a subzone.
secure delegation: a signed name containing a delegation (NS RRset) and a signed DS RRset, meaning a delegation to a signed subzone.
insecure delegation: a signed name containing a delegation (NS RRset) but lacking a DS RRset, meaning a delegation to an unsigned subzone.
Opt-In insecure delegation: an unsigned name containing only a delegation NS RRset. The covering NSEC record uses the Opt-In methodology described in this document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [2]. That's the official rulebook for these words, so read them carefully 🫶
3. Experimental Status 🧪
This document describes an EXPERIMENTAL extension to DNSSEC. It interoperates with non-experimental DNSSEC using the technique described in [7]. This experiment is identified with the following private algorithms (using algorithm 253):
3.optin.verisignlabs.com: an alias for DNSSEC algorithm 3, DSA.5.optin.verisignlabs.com: an alias for DNSSEC algorithm 5, RSASHA1.
Servers wishing to sign and serve zones that utilize Opt-In MUST sign the zone with only one or more of these private algorithms and MUST NOT use any other algorithms. 🚨
Resolvers MUST NOT apply the Opt-In validation rules described in this document unless a zone is signed using one or more of these private algorithms. 🚨
This experimental protocol relaxes the restriction that validators MUST ignore the setting of the NSEC bit in the type map, as specified in RFC 4035 [6] Section 5.4. Bold move, but it's for science 🔬
The rest of this document assumes that the servers and resolvers involved are aware of and are involved in this experiment 🌈
4. Protocol Additions 🍓
In DNSSEC, delegation NS RRsets aren't signed. They're instead accompanied by an NSEC RRset with the same name and (possibly) a DS record. The subzone's security status is determined by whether the DS RRset is present or absent, and the NSEC record cryptographically proves which one it is. Opt-In expands this by letting insecure delegations exist inside an otherwise signed zone without the matching NSEC record at the delegation's owner name. These insecure delegations get proven insecure by a covering NSEC record ✨
Since this changes how NSEC records are interpreted, resolvers must be able to tell standard DNSSEC NSEC records apart from Opt-In NSEC records. This is done by "tagging" the NSEC records that cover (or might cover) insecure delegation nodes. The tag is the absence of the NSEC bit in the type map. Since the NSEC bit in the type map only says the record itself exists, this bit is redundant and safe to use as a tag. Clever, right? 🧠
An Opt-In tagged NSEC record does not assert the (non)existence of the delegations it covers, except for a delegation with the same name. This lets you add or remove those delegations without recalculating or resigning records in the NSEC chain 💅 However, Opt-In tagged NSEC records do assert the (non)existence of other RRsets.
An Opt-In NSEC record MAY have the same name as an insecure delegation. In that case, the delegation is proven insecure by the lack of a DS bit in the type map, and the signed NSEC record does assert that the delegation exists.
Zones using Opt-In MAY contain a mix of Opt-In tagged NSEC records and standard DNSSEC NSEC records. If an NSEC record is not Opt-In, there MUST NOT be any insecure delegations (or any other records) between it and the RRsets indicated by the 'next domain name' in the NSEC RDATA. If it is Opt-In, there MUST only be insecure delegations between it and the next node indicated by the 'next domain name' in the NSEC RDATA. Rules are rules, bestie 🙈
In summary:
- An Opt-In NSEC type is identified by a zero-valued (or not-specified) NSEC bit in the type bit map of the NSEC record.
- A standard DNSSEC NSEC type is identified by a one-valued NSEC bit in the type bit map of the NSEC record.
and
- An Opt-In NSEC record does not assert the non-existence of a name between its owner name and "next" name, although it does assert that any name in this span MUST be an insecure delegation.
- An Opt-In NSEC record does assert the (non)existence of RRsets with the same owner name.
4.1. Server Considerations 🖥️
Opt-In adds some new requirements for authoritative DNS servers. Be ready, servers 💖
4.1.1. Delegations Only
This specification dictates that only insecure delegations may exist between the owner and "next" names of an Opt-In tagged NSEC record. Signing tools MUST NOT generate signed zones that violate this restriction. Servers MUST refuse to load and/or serve zones that violate this restriction. Servers also MUST reject AXFR or IXFR responses that violate this restriction. No loopholes, periodt 🚫
4.1.2. Insecure Delegation Responses
When returning an Opt-In insecure delegation, the server MUST return the covering NSEC RRset in the Authority section.
In standard DNSSEC, NSEC records already have to be returned along with the insecure delegation. The main difference this proposal brings is that the Opt-In tagged NSEC record will have a different owner name from the delegation RRset. This may require implementations to search for the covering NSEC RRset 🔍
4.1.3. Dynamic Update
Opt-In changes the semantics of Secure DNS Dynamic Update [9]. In particular, it creates the need for rules that describe when to add or remove a delegation name from the NSEC chain. This document does not attempt to define these rules 🙃 Until those rules are defined, servers MUST NOT process DNS Dynamic Update requests against zones that use Opt-In NSEC records. Servers SHOULD return responses to update requests with RCODE=REFUSED. Not today, updates 💀
4.2. Client Considerations 💜
Opt-In adds some new requirements for security-aware resolvers, whether they're caching or otherwise 🫶
4.2.1. Delegations Only
As stated in Section 4.1 above, this specification restricts the namespace covered by Opt-In tagged NSEC records to insecure delegations only. Clients are not expected to take any special measures to enforce this restriction. Instead, it's an underlying assumption that clients may rely on 🧚
4.2.2. Validation Process Changes 🔐
This specification does not change the resolver's resolution algorithm. However, it does change the DNSSEC validation process. So the lookup flow stays the same, but the checking part gets a glow-up ✨
Part 1 ends here, and the rest of this slay is coming up next 🌈💖
4.2.2.1. Referrals ✨
Okay so resolvers MUST be able to use Opt-In tagged NSEC records to cryptographically prove the validity and security status (as insecure) of a referral 💅 Here's how resolvers figure out the security status of the referred-to zone:
- Bestie, in standard DNSSEC, the security status gets proven by whether a DS RRset exists at the same name as the delegation 🔐. If the DS RRset is there, the referred-to zone is signed. If it's missing, you prove that with a verified NSEC record of the same name that does not have the DS bit set in the type map. That NSEC record MAY also be tagged as Opt-In 🌸
- With Opt-In, the security status is proven by a DS record (for signed) or by a verified Opt-In tagged NSEC record that covers the delegation name 🦋. That means the NSEC record does not have the NSEC bit set in the type map, and the delegation name falls between the NSEC's owner and "next" name.
Using Opt-In does not substantially change how referrals work in DNSSEC, and it's giving main character energy 💖. At every delegation point, the resolver will have cryptographic proof that the referred-to subzone is signed or unsigned ✨.
4.2.2.2. Queries for DS Resource Records 🎀
Since queries for DS records are directed to the parent side of a zone cut (see [5], Section 5), negative responses to these queries may be covered by an Opt-In flagged NSEC record 🧚.
Resolvers MUST be able to use Opt-In tagged NSEC records to cryptographically prove the validity and security status of negative responses to queries for DS records 🔥. In particular, a NOERROR/NODATA (i.e., RCODE=3, but the answer section is empty) response to a DS query may be proven by an Opt-In flagged covering NSEC record, rather than an NSEC record matching the query name 💅.
4.2.3. NSEC Record Caching 🍓
Caching resolvers MUST be able to retrieve the appropriate covering Opt-In NSEC record when returning referrals that need them 🫶. This is where it gets different from standard DNSSEC: the covering NSEC will not have the same owner name as the delegation. Some implementations may have to use new methods for finding these NSEC records 👑.
4.2.4. Use of the AD bit 🙈
The AD bit, as defined by [3] and [6], MUST NOT be set when:
- sending a Name Error (
RCODE=3) response where the covering NSEC is tagged as Opt-In. - sending an Opt-In insecure delegation response, unless the covering (Opt-In) NSEC record's owner name equals the delegation name.
- sending a
NOERROR/NODATAresponse when query type is DS and the covering NSEC is tagged as Opt-In, unless NSEC record's owner name matches the query name.
This rule is based on what the Opt-In NSEC record actually proves 🤓. For names that exist between the Opt-In NSEC record's owner and "next" names, the Opt-In NSEC record cannot prove the non-existence or existence of the name. So not all data in the response has been cryptographically verified, which means the AD bit cannot be set 💀.
5. Benefits 💜
Using Opt-In lets administrators of large and/or changing delegation-centric zones keep the overhead of maintaining the security of the zone way lower 🧁.
Opt-In does this by getting rid of the need for NSEC records for insecure delegations. In a zone with a huge number of delegations to unsigned subzones, that can lead to substantial space savings (both in memory and on disk) 🤑. Opt-In also lets you add or remove insecure delegations without touching the NSEC record chain. Zones that update insecure delegations all the time (e.g., Top-Level Domains (TLDs)) can skip the substantial overhead of modifying and resigning the affected NSEC records 🌈.
6. Example 🦋
Consider the zone EXAMPLE shown below. This is a zone where all of the NSEC records are tagged as Opt-In 💅.
Example A: Fully Opt-In Zone.
EXAMPLE. SOA ...
EXAMPLE. RRSIG SOA ...
EXAMPLE. NS FIRST-SECURE.EXAMPLE.
EXAMPLE. RRSIG NS ...
EXAMPLE. DNSKEY ...
EXAMPLE. RRSIG DNSKEY ...
EXAMPLE. NSEC FIRST-SECURE.EXAMPLE. (
SOA NS RRSIG DNSKEY )
EXAMPLE. RRSIG NSEC ...
FIRST-SECURE.EXAMPLE. A ...
FIRST-SECURE.EXAMPLE. RRSIG A ...
FIRST-SECURE.EXAMPLE. NSEC NOT-SECURE-2.EXAMPLE. A RRSIG
FIRST-SECURE.EXAMPLE. RRSIG NSEC ...
NOT-SECURE.EXAMPLE. NS NS.NOT-SECURE.EXAMPLE.
NS.NOT-SECURE.EXAMPLE. A ...
NOT-SECURE-2.EXAMPLE. NS NS.NOT-SECURE.EXAMPLE.
NOT-SECURE-2.EXAMPLE NSEC SECOND-SECURE.EXAMPLE NS RRSIG
NOT-SECURE-2.EXAMPLE RRSIG NSEC ...
SECOND-SECURE.EXAMPLE. NS NS.ELSEWHERE.
SECOND-SECURE.EXAMPLE. DS ...
SECOND-SECURE.EXAMPLE. RRSIG DS ...
SECOND-SECURE.EXAMPLE. NSEC EXAMPLE. NS RRSIG DNSKEY
SECOND-SECURE.EXAMPLE. RRSIG NSEC ...
UNSIGNED.EXAMPLE. NS NS.UNSIGNED.EXAMPLE.
NS.UNSIGNED.EXAMPLE. A ...
Example A.In this example, a query for a signed RRset (e.g., "FIRST-SECURE.EXAMPLE A") or a secure delegation ("WWW.SECOND-SECURE.EXAMPLE A") will result in a standard DNSSEC response 🎀.
A query for a nonexistent RRset will result in a response that differs from standard DNSSEC in these ways: the NSEC record will be tagged as Opt-In, there may be no NSEC record proving the non-existence of a matching wildcard record, and the AD bit will not be set 🙈.
A query for an insecure delegation RRset (or a referral) will return both the answer (in the Authority section) and the corresponding Opt-In NSEC record to prove that it is not secure 🔐.
Example A.1: Response to query for WWW.UNSIGNED.EXAMPLE. A
RCODE=NOERROR, AD=0
Answer Section:
Authority Section:
UNSIGNED.EXAMPLE. NS NS.UNSIGNED.EXAMPLE
SECOND-SECURE.EXAMPLE. NSEC EXAMPLE. NS RRSIG DS
SECOND-SECURE.EXAMPLE. RRSIG NSEC ...
Additional Section:
NS.UNSIGNED.EXAMPLE. A ...
Example A.1In the Example A.1 zone, the EXAMPLE. node MAY use either style of NSEC record, because there are no insecure delegations between it and the next node, FIRST-SECURE.EXAMPLE. 🌸 In other words, Example A would still be a valid zone if the NSEC record for EXAMPLE. was changed to the following RR:
EXAMPLE. NSEC FIRST-SECURE.EXAMPLE. (SOA NS
RRSIG DNSKEY NSEC )However, the other NSEC records (FIRST-SECURE.EXAMPLE. and SECOND-SECURE.EXAMPLE.) MUST be tagged as Opt-In because there are insecure delegations in the range they define (NOT-SECURE.EXAMPLE. and UNSIGNED.EXAMPLE., respectively) 🧚.
NOT-SECURE-2.EXAMPLE. is an example of an insecure delegation that is part of the NSEC chain and also covered by an Opt-In tagged NSEC record. Because NOT-SECURE-2.EXAMPLE. is a signed name, it cannot be removed from the zone without modifying and resigning the prior NSEC record. Delegations with names that fall between NOT-SECURE-2.EXAMPLE. and SECOND-SECURE.EXAMPLE. may be added or removed without resigning any NSEC records 🫶.
7. Transition Issues 🌈
Opt-In is not backwards compatible with standard DNSSEC and is considered experimental 🧪. Standard DNSSEC-compliant implementations would not recognize Opt-In tagged NSEC records as different from standard NSEC records. Because of this, standard DNSSEC implementations, if they were to validate Opt-In style responses, would reject all Opt-In insecure delegations within a zone as invalid 💀. However, by only signing with private algorithms, standard DNSSEC implementations will treat Opt-In responses as unsigned 🌸.
It should be noted that all elements in the resolution path between (and including) the validator and the authoritative name server must be aware of the Opt-In experiment and implement the Opt-In semantics for successful validation to be possible 👑. This especially includes any caching middleboxes between the validator and authoritative name server 📦.
8. Security Considerations 🚨
Opt-In allows for unsigned names, in the form of delegations to unsigned subzones, to exist within an otherwise signed zone. All unsigned names are, by definition, insecure, and their validity or existence cannot be cryptographically proven 😭.
In general:
- Records with unsigned names (whether or not existing) suffer from the same vulnerabilities as records in an unsigned zone. These vulnerabilities are described in more detail in [12] (note in particular Sections 2.3, "Name Games" and 2.6, "Authenticated Denial").
- Records with signed names have the same security whether or not Opt-In is used.
Note that with or without Opt-In, an insecure delegation may have its contents undetectably altered by an attacker 🕵️♀️. Because of this, the primary difference in security that Opt-In introduces is the loss of the ability to prove the existence or nonexistence of an insecure delegation within the span of an Opt-In NSEC record.
In particular, this means that a malicious entity may be able to insert or delete records with unsigned names. These records are normally NS records, but this also includes signed wildcard expansions (while the wildcard record itself is signed, its expanded name is an unsigned name), which can be undetectably removed or used to replace an existing unsigned delegation 🥀.
For example, if a resolver received the following response from the example zone above:
Example S.1: Response to query for WWW.DOES-NOT-EXIST.EXAMPLE. A
RCODE=NOERROR
Answer Section:
Authority Section:
DOES-NOT-EXIST.EXAMPLE. NS NS.FORGED.
EXAMPLE. NSEC FIRST-SECURE.EXAMPLE. SOA NS \
RRSIG DNSKEY
EXAMPLE. RRSIG NSEC ...
Additional Section:
Attacker has forged a nameThe resolver would have no choice but to believe that the referral to NS.FORGED. is valid. If a wildcard existed that would have been expanded to cover "WWW.DOES-NOT-EXIST.EXAMPLE.", an attacker could have undetectably removed it and replaced it with the forged delegation 😱.
Note that being able to add a delegation is functionally equivalent to being able to add any record type: an attacker merely has to forge a delegation to the nameserver under his/her control and place whatever records are needed at the subzone apex 🚩.
While in particular cases, this issue may not present a significant security problem, in general it should not be lightly dismissed. Therefore, it is strongly RECOMMENDED that Opt-In be used sparingly. In particular, zone signing tools SHOULD NOT default to Opt-In, and MAY choose not to support Opt-In at all 🛑.
9. Acknowledgments 🫶
The contributions, suggestions, and remarks of the following persons (in alphabetic order) to this document are acknowledged 💖:
Mats Kolkman, Edward Lewis, Ted Lindgreen, Rip Loomis, Bill Manning, Dan Massey, Scott Rose, Mike Schiraldi, Jakob Schlyter, Brian Wellington.
10. References 📚
10.1. Normative References ✨
okay so these are the must-read docs 📚 you need in your back pocket before any of this makes sense. no cap, skipping them is a whole mood-killer 💀
[1] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[3] Wellington, B. and O. Gudmundsson, "Redefinition of DNS Authenticated Data (AD) bit", RFC 3655, November 2003.
[4] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "DNS Security Introduction and Requirements", RFC 4033, March 2005.
[5] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005.
[6] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005.
[7] Blacka, D., "DNSSEC Experiments", RFC 4955, July 2007.
10.2. Informative References 🦋
these ones are the extra reading that adds the context 🌸 nice to have, not required
[8] Elz, R. and R. Bush, "Clarifications to the DNS Specification", RFC 2181, July 1997.
[9] Wellington, B., "Secure Domain Name System (DNS) Dynamic Update", RFC 3007, November 2000.
[10] Lewis, E., "DNS Security Extension Clarification on Zone Status", RFC 3090, March 2001.
[11] Conrad, D., "Indicating Resolver Support of DNSSEC", RFC 3225, December 2001.
[12] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name System (DNS)", RFC 3833, August 2004.
Appendix A. Implementing Opt-In Using "Views" 🧚
okay this appendix is giving clever 🙈 sometimes it's convenient to build an Opt-In zone by mashing two separately kept "views" of a zone together at request time. and "view" here just means a particular version of a zone, not some special DNS implementation feature. no cap, it's not a fancy new thing, just a version 💅
so you've got two views. the secure view is a fully signed zone that uses Opt-In tagged NSEC records. the insecure (or legacy) view has zero DNSSEC info in it. it's helpful (not strictly necessary tho ✨) if the secure view is a subset of the insecure view, minus the DNSSEC records.
the only RRsets that may solely exist in the insecure view are non-zone-apex NS RRsets. so everything else, meaning all non-NS RRsets and the zone apex NS RRset, MUST be signed and in the secure view. periodt 🔥
these two views get combined at request time to act like one virtual Opt-In zone. the algorithm below runs for each query:
V_A is the secure view as described above.
V_B is the insecure view as described above.
R_A is a response generated from V_A, following standard DNSSEC.
R_B is a response generated from V_B, following DNS resolution as
per RFC 1035 [1].
R_C is the response generated by combining R_A with R_B, as
described below.
A query is DNSSEC-aware if it either has the DO bit [11] turned on
or is for a DNSSEC-specific record type.
1. If V_A is a subset of V_B and the query is not DNSSEC-aware,
generate and return R_B, otherwise
2. Generate R_A.
3. If R_A's RCODE != NXDOMAIN, return R_A, otherwise
4. Generate R_B and combine it with R_A to form R_C:
For each section (ANSWER, AUTHORITY, ADDITIONAL), copy the
records from R_A into R_B, EXCEPT the AUTHORITY section SOA
record, if R_B's RCODE = NOERROR.
5. Return R_C.Authors' Addresses 💌
meet the people who wrote this whole thing 🫶
Roy Arends
Nominet
Sandford Gate
Sandy Lane West
Oxford OX4 6LB
UNITED KINGDOM
Phone: +44 1865 332211
EMail: roy@nominet.org.uk
Mark Kosters
VeriSign, Inc.
21355 Ridgetop Circle
Dulles, VA 20166
US
Phone: +1 703 948 3200
EMail: mkosters@verisign.com
URI: http://www.verisignlabs.com
David Blacka
VeriSign, Inc.
21355 Ridgetop Circle
Dulles, VA 20166
US
Phone: +1 703 948 3200
EMail: davidb@verisign.com
URI: http://www.verisignlabs.comFull Copyright Statement 💖
the legal bit, but make it cute ✨ the document is Copyright (C) The IETF Trust (2007). it's covered by the rights, licenses and restrictions in BCP 78, and apart from what's set out there, the authors keep all their rights.
this document and the info in it are provided on an "AS IS" basis, and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property 🔥
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copies of IPR disclosures sent to the IETF Secretariat, any assurances of licenses, or the results of an attempt to get a general license or permission for implementers or users are all listed in the IETF's online IPR repository at http://www.ietf.org/ipr.
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Acknowledgement 🫶
funding for the RFC Editor function is currently provided by the Internet Society 🌈
📦 where this page comes from
- ietf: rfc4956 2007-07
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