wdiff rfc9154.original rfc9154.txt

Network Working Group

Internet Engineering Task Force (IETF) J. Gould
Internet-Draft
Request for Comments: 9154 R. Wilhelm
Intended status:
Category: Standards Track VeriSign, Verisign, Inc.
Expires: 30
ISSN: 2070-1721 December 2021 28 June 2021

Extensible Provisioning Protocol (EPP) Secure Authorization Information
for Transfer
draft-ietf-regext-secure-authinfo-transfer-07

Abstract

The Extensible Provisioning Protocol (EPP), in RFC 5730, (EPP) (RFC 5730) defines the use
of authorization information to authorize a transfer of an EPP
object, such as a domain name, between clients that are referred to
as registrars. "registrars". Object-specific, password-based authorization
information (see RFC RFCs 5731 and RFC 5733) is commonly used, used but raises
issues related to the security, complexity, storage, and lifetime of
authentication information. This document defines an operational
practice, using the EPP RFCs, that leverages the use of strong random
authorization information values that are short-lived, short lived, not stored by
the client, and stored by the server using a cryptographic hash that
provides for secure authorization information that can safely be used
for object transfers.

Status of This Memo

This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."

This Internet-Draft will expire on 30 December 2021.
https://www.rfc-editor.org/info/rfc9154.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info)
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Simplified Revised BSD License.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions Used in This Document . . . . . . . . . . . . 4
2. Registrant, Registrar, Registry . . . . . . . . . . . . . . . 5
3. Signaling Client and Server Support . . . . . . . . . . . . . 6
4. Secure Authorization Information . . . . . . . . . . . . . . 7
4.1. Secure Random Authorization Information . . . . . . . . . 7
4.2. Authorization Information Time-To-Live Time To Live (TTL) . . . . . . 8
4.3. Authorization Information Storage and Transport . . . . . 8
4.4. Authorization Information Matching . . . . . . . . . . . 9
5. Create, Transfer, and Secure Authorization Information . . . 10
5.1. Create <Create> Command . . . . . . . . . . . . . . . . . . . . . 10
5.2. Update <Update> Command . . . . . . . . . . . . . . . . . . . . . 12
5.3. Info <Info> Command and Response . . . . . . . . . . . . . . . . 15
5.4. Transfer <Transfer> Request Command . . . . . . . . . . . . . . . . 17
6. Transition Considerations . . . . . . . . . . . . . . . . . . 18
6.1. Transition Phase 1 - Features . . . . . . . . . . . . . . 20
6.2. Transition Phase 2 - Storage . . . . . . . . . . . . . . 21
6.3. Transition Phase 3 - Enforcement . . . . . . . . . . . . 21
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7.1. XML Namespace . . . . . . . . . . . . . . . . . . . . . . 21
7.2. EPP Extension Registry . . . . . . . . . . . . . . . . . 22
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 22
8.1. Verisign EPP SDK . . . . . . . . . . . . . . . . . . . . 23
8.2. RegistryEngine EPP Service . . . . . . . . . . . . . . . 23
9. Security Considerations . . . . . . . . . . . . . . . . . . . 24
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24
11.
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
11.1.
9.1. Normative References . . . . . . . . . . . . . . . . . . 24
11.2.
9.2. Informative References . . . . . . . . . . . . . . . . . 25
Appendix A. Change History . . . . . . . . . . . . . . . . . . . 26
A.1. Change from 00 to 01 . . . . . . . . . . . . . . . . . . 26
A.2. Change from 01 to 02 . . . . . . . . . . . . . . . . . . 26
A.3. Change from 02 to 03 . . . . . . . . . . . . . . . . . . 26
A.4. Change from 03 to REGEXT 00 . . . . . . . . . . . . . . . 28
A.5. Change from REGEXT 00 to REGEXT 01 . . . . . . . . . . . 28
A.6. Change from REGEXT 01 to REGEXT 02 . . . . . . . . . . . 28
A.7. Change from REGEXT 02 to REGEXT 03 . . . . . . . . . . . 28
A.8. Change from REGEXT 03 to REGEXT 04 . . . . . . . . . . . 28
A.9. Change from REGEXT 04 to REGEXT 05 . . . . . . . . . . . 28
A.10. Change from REGEXT 05 to REGEXT 06 . . . . . . . . . . . 29
A.11. Change from REGEXT 06 to REGEXT 07 . . . . . . . . . . . 29
Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31

1. Introduction

The Extensible Provisioning Protocol (EPP), in [RFC5730], (EPP) [RFC5730] defines the use
of authorization information to authorize a transfer of an EPP
object, such as a domain name, between clients that are referred to
as registrars. "registrars". The authorization information is object-specific object specific
and has been defined in the EPP "Extensible Provisioning Protocol (EPP)
Domain Name Mapping, in [RFC5731], Mapping" [RFC5731] and
the EPP "Extensible Provisioning Protocol
(EPP) Contact Mapping, in [RFC5733], Mapping" [RFC5733] as password-based authorization
information. Other authorization mechanisms can be used, but in
practice the password-based authorization information has been used
at the time of object create, creation, managed with the object update, and
used to authorize an object transfer request. What has not been
considered is the security of the authorization information
that information, which
includes the complexity of the authorization information, the
time-to-live Time To
Live (TTL) of the authorization information, and where and how the
authorization information is stored.

The current/original lifecycle for authorization information involves
long-term storage of encrypted (not hashed) passwords, which presents
a significant latent risk of password compromise and is not
consistent with current best practices. The mechanisms in this
document provide a way to avoid long-term password storage entirely, entirely
and to only require the storage of hashed (not retrievable) passwords
instead of encrypted passwords.

This document defines an operational practice, using the EPP RFCs,
that leverages the use of strong, random authorization information
values that are short-lived, that are short lived, not stored by the client, and
that are stored by
the server using a cryptographic hash to provide secure authorization
information used for transfers. This operational practice can be
used to support transfers of any EPP object, where the domain name
object as defined in [RFC5731] is used in this document for
illustration purposes. Elements of the practice may be used to
support the secure use of the authorization information for purposes
other than transfer, but any other purposes and the applicable
elements are out-of-scope out of scope for this document.

The overall goal is to have strong, random authorization information
values,
values that are short-lived, short lived and that are either not stored or stored as a
cryptographic hash values by the non-responsible parties. In a
registrant, registrar, and registry model, the registrant registers
the object through the registrar to the registry. The registrant is
the responsible party party, and the registrar and the registry are the
non-responsible parties. EPP is a protocol between the registrar and
the registry, where the registrar is referred to as the client "client" and
the registry is referred to as the server. "server". The following are the
elements of the operational practice and how the existing features of
the EPP RFCs can be leveraged to satisfy them:

"Strong

Strong Random Authorization Information": Information: The EPP RFCs define the
password-based authorization information value using an XML
schema "normalizedString" type, so they don't restrict what can
be used in any substantial way. This operational practice
defines the recommended mechanism for creating a strong random
authorization value, value that would be generated by the client.
"Short-Lived

Short-Lived Authorization Information": Information: The EPP RFCs don't explicitly
support short-lived authorization information or a
time-to-live (TTL) TTL for
authorization information, but there are EPP RFC features that
can be leveraged to support short-lived authorization
information. All of these features are compatible with the EPP
RFCs, though not mandatory to implement. In section As stated in
Section 2.6 of [RFC5731] it states that [RFC5731], authorization information is assigned
when a domain object is created, which results in long-
lived long-lived
authorization information. This specification changes the nature
of the authorization information from long lived to be short-lived. short lived.
If authorization information is set only when there is a transfer is in
process, the server needs to support an empty authorization
information value on create, support setting and unsetting
authorization information, and support automatically unsetting
the authorization information upon a successful transfer. All of
these features can be supported by the EPP RFCs.
"Storing

Storing Authorization Information Securely": Securely: The EPP RFCs don't
specify where and how the authorization information is stored in
the client or the server, so there are no restrictions to define on
defining an operational practice for storing the authorization
information securely. The operational practice will require the
client to not store the authorization information and will
require the server to store the authorization information using a
cryptographic hash, hash with at least a 256-bit hash function, such as
SHA-256 [FIPS-180-4], and with a per-authorization information
random salt, salt with at least 128 bits. Returning the authorization
information set in an EPP info response will not be supported.

1.1. Conventions Used in This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.

XML [W3C.REC-xml-20081126] is case sensitive. Unless stated
otherwise, XML specifications and examples provided in this document
MUST be interpreted in the character case presented in order to
develop a conforming implementation.

In examples, "C:" represents lines sent by a protocol client and "S:"
represents lines returned by a protocol server. Indentation and
white
empty space in examples are provided only to illustrate element
relationships and are not a required feature of this protocol.

The examples reference XML namespace prefixes that are used for the
associated XML namespaces. Implementations MUST NOT depend on the
example XML namespaces and instead employ a proper namespace-aware
XML parser and serializer to interpret and output the XML documents.
The example namespace prefixes used and their associated XML
namespaces include:

"domain": include the following:

domain: urn:ietf:params:xml:ns:domain-1.0
"contact":

contact: urn:ietf:params:xml:ns:contact-1.0

2. Registrant, Registrar, Registry

The EPP RFCs refer to client "client" and server, "server", but when it comes to
transfers, there are three types of actors that are involved. This
document will refer to the these actors as registrant, registrar, "registrant", "registrar", and
registry.
"registry". [RFC8499] defines these terms formally for the Domain
Name System (DNS). The terms are further described below to cover
their roles as actors of using the authorization information in the
transfer process of any object in the registry, such as a domain name
or a contact:

"registrant":

Registrant: [RFC8499] defines the registrant as "an individual or
organization on whose behalf a name in a zone is registered by
the registry". registry." The registrant can be the owner of any object in
the registry, such as a domain name or a contact. The registrant
interfaces with the registrar for provisioning the objects. A
transfer is coordinated by the registrant to transfer the
sponsorship of the object from one registrar to another. The
authorization information is meant to authenticate the registrant
as the owner of the object to the non-sponsoring registrar and to
authorize the transfer.
"registrar":

Registrar: [RFC8499] defines the registrar as "a service provider
that acts as a go-between for registrants and registries". registries." The
registrar interfaces with the registrant for the provisioning of
objects, such as domain names and contacts, and with the
registries to satisfy the registrant's provisioning requests. A
registrar may (1) directly interface with the registrant or may
(2) indirectly interface with the registrant, typically through
one or more resellers. Implementing a transfer using secure
authorization information extends through the registrar's
reseller channel up to the direct interface with the registrant.
The registrar's interface with the registries uses EPP. The
registrar's interface with its reseller channel or the registrant
is registrar-specific. registrar specific. In the EPP RFCs, the registrar is
referred to as the "client", since EPP is the protocol used
between the registrar and the registry. The sponsoring registrar
is the authorized registrar to manage objects on behalf of the
registrant. A non-sponsoring registrar is not authorized to
manage objects on behalf of the registrant. A transfer of an
object's sponsorship is from one registrar, referred to as the
losing registrar,
"losing registrar", to another registrar, referred to as the
gaining registrar.
"registry":
"gaining registrar".

Registry: [RFC8499] defines the registry as "the administrative
operation of a zone that allows registration of names within the
zone". that
zone." The registry typically interfaces with the registrars
over EPP and generally does not interact directly with the
registrant. In the EPP RFCs, the registry is referred to as the
"server", since EPP is the protocol used between the registrar
and the registry. The registry has a record of the sponsoring
registrar for each object and provides the mechanism (over EPP)
to coordinate a transfer of an object's sponsorship between
registrars.

3. Signaling Client and Server Support

This document does not define a new protocol but protocol; rather, it defines an
operational practice using the existing EPP protocol, features, where the client
and the server can signal support for the operational practice using
a namespace URI in the login and greeting extension services. The
namespace URI "urn:ietf:params:xml:ns:epp:secure-authinfo-transfer-
1.0" is used to signal support for the operational practice. The
client includes the namespace URI in an <svcExtension> <extURI>
element of the [RFC5730] <login> Command. command [RFC5730]. The server includes the
namespace URI in an <svcExtension> <extURI> element of the [RFC5730]
Greeting. greeting
[RFC5730].

A client that receives the namespace URI in the server's Greeting greeting
extension services can expect the following supported behavior by the
server:

1. Support for an empty authorization information value with a create
<create> command.

2. Support for unsetting authorization information with an update <update>
command.

3. Support for validating authorization information with an info <info>
command.

4. Support for not returning an indication of whether the
authorization information is set or unset to the non-sponsoring
registrar.

5. Support for returning an empty authorization information value to
the sponsoring registrar when the authorization information is
set in an info response.

6. Support allowing for allowing the passing of a matching non-empty
authorization information value to authorize a transfer.

7. Support for automatically unsetting the authorization information
upon a successful completion of a transfer.

A server that receives the namespace URI in the client's <login>
Command
command extension services, services can expect the following supported
behavior by the client:

1. Support for the generation of authorization information using a
secure random value.

2. Support for only setting the authorization information when there is a
transfer is in process.

4. Secure Authorization Information

The authorization information in the EPP RFCs ([RFC5731] and [RFC5733]) that support transfer use password-based
authorization information ([RFC5731] to support transfer with the <domain:pw>
element [RFC5731] and [RFC5733] with the <contact:pw> element). element [RFC5733]. Other
EPP objects that support password-based authorization information for
transfer can use the
Secure Authorization Information secure authorization information as defined in this
document. For the authorization information to be secure, it must be
generated using a strong random value and have a short time-to-live (TTL). TTL. The
security of the authorization information is defined in the following
sections.

4.1. Secure Random Authorization Information

For authorization information to be secure, it MUST be generated
using a secure random value. The authorization information is
treated as a password, and the required length L of a password,
rounded up to the largest whole number, is based on the size N of the
set of characters and the desired entropy H, in the equation L =
ROUNDUP(H / log2 log_2 N). Given a target entropy, the required length
can be calculated after deciding on the set of characters that will
be randomized. In accordance with current best practices and noting
that the authorization information is a machine-generated value, the
implementation SHOULD use at least 128 bits of entropy as the value
of H. The lengths below are calculated using that value.

Calculation of the required length with 128 bits of entropy and with
the set of all printable ASCII characters except space (0x20), which
consists of the 94 characters 0x21-0x7E. 0x21-0x7E:

ROUNDUP(128 / log2 log_2 94) =~ ROUNDUP(128 / 6.55) =~ ROUNDUP(19.54) = 20

Calculation of the required length with 128 bits of entropy and with
the set of case insensitive case-insensitive alphanumeric characters, which consists
of 36 characters (a-z A-Z 0-9). 0-9):

ROUNDUP(128 / log2 log_2 36) =~ ROUNDUP(128 / 5.17) =~ ROUNDUP(24.76) = 25

The strength of the random authorization information is dependent on
the random number generator. Suitably strong random number
generators are available in a wide variety of implementation
environments, including the interfaces listed in Sections 7.1.2 and
7.1.3 of [RFC4086]. In environments that do not provide interfaces
to strong random number generators, the practices defined in
[RFC4086] and section Section 4.7.1 of the NIST Federal Information
Processing Standards (FIPS) Publication 140-2 [FIPS-140-2] can be
followed to produce random values that will be resistant to attack.
(Note: FIPS 140-2 has been superseded by FIPS 140-3, but FIPS 140-3
does not contain information regarding random number generators.)

4.2. Authorization Information Time-To-Live Time To Live (TTL)

The authorization information SHOULD only be set when there is a transfer is
in process. This implies that the authorization information has a Time-To-Live (TTL)
TTL by which the authorization information is cleared when the TTL
expires. The EPP RFCs have no definition of do not provide definitions for TTL, but since
the server supports the setting and unsetting of the authorization
information by the sponsoring registrar, the sponsoring registrar can
apply a TTL based on client policy. The TTL client policy may be
based on proprietary registrar-specific criteria, which provides for
a transfer-specific TTL tuned for the particular circumstances of the
transaction. The sponsoring registrar will be aware of the TTL TTL, and
the sponsoring registrar MUST inform the registrant of the TTL when
the authorization information is provided to the registrant.

4.3. Authorization Information Storage and Transport

To protect the disclosure of the authorization information, the
following requirements apply:

1. The authorization information MUST be stored by the registry
using a strong one-way cryptographic hash, hash with at least a 256-bit
hash function, such as SHA-256 [FIPS-180-4], and with a
per-authorization per-
authorization information random salt, salt with at least 128 bits.

2. Empty An empty authorization information value MUST be stored as an
undefined value that is referred to as a NULL "NULL" value. The
representation of a NULL (undefined) value is dependent on the
type of database used.

3. The authorization information MUST NOT be stored by the losing
registrar.

4. The authorization information MUST only be stored by the gaining
registrar as a "transient" value in support of the transfer
process.

5. The plain text plain-text version of the authorization information MUST NOT
be written to any logs by a registrar or the registry, nor
otherwise recorded where it will persist beyond the transfer
process.

6. All communication that includes the authorization information
MUST be over an encrypted channel, such as defined in [RFC5734] channel (for example, see [RFC5734])
for EPP.

7. The registrar's interface for communicating the authorization
information with the registrant MUST be over an authenticated and
encrypted channel.

4.4. Authorization Information Matching

To support the authorization information TTL, as defined described in
Section 4.2, the authorization information must have either a set or
unset state. Authorization information that is unset is stored with
a NULL (undefined) value. Based on the requirement to store the
authorization information using a strong one-way cryptographic hash,
as defined described in Section 4.3, authorization information that is set is
stored with a non-NULL hashed value. The empty authorization
information value is used as input in both the create <create> command
(Section 5.1) and the update <update> command (Section 5.2) to define the
unset state. The matching of the authorization information in the info
<info> command (Section 5.3) and the transfer <transfer> request command
(Section 5.4) is based on the following rules:

1. Any input authorization information value MUST NOT match an unset
authorization information value. This includes empty For example, in [RFC5731] the
input <domain:pw>2fooBAR</domain:pw> must not match an unset
authorization information, such as information value that used <domain:null/> or <domain:pw/>
in [RFC5731], and non-empty authorization information, such as
<domain:pw>2fooBAR</domain:pw> in [RFC5731].
<domain:pw/>.

2. An empty input authorization information value MUST NOT match any
set authorization information value.

3. A non-empty input authorization information value MUST be hashed
and matched against the set authorization information value,
which is stored using the same hash algorithm.

5. Create, Transfer, and Secure Authorization Information

To secure the transfer process using secure authorization
information, information
as defined described in Section 4, the client and server need to implement
steps where the authorization information is set only when a transfer
is actively in process and ensure that the authorization information
is stored securely and transported only over secure channels. The
steps in for management of the authorization information for transfers include:
include the following:

1. Registrant The registrant requests to register the object with the
registrar.
Registrar The registrar sends the create command, <create> command with an
empty authorization information value, value to the registry, as defined
described in Section 5.1.

2. Registrant The registrant requests from the losing registrar the
authorization information to provide to the gaining registrar.

3. Losing The losing registrar generates a secure random authorization
information value, value and sends it to the registry registry, as defined described in
Section 5.2, and then provides it to the registrant.

4. Registrant The registrant provides the authorization information value to
the gaining registrar.

5. Gaining The gaining registrar optionally verifies the authorization
information with the info <info> command to the registry, as defined described
in Section 5.3.

6. Gaining The gaining registrar sends the transfer request with the
authorization information to the registry, as defined described in
Section 5.4.

7. If the transfer successfully completes, completes successfully, the registry
automatically unsets the authorization information; otherwise otherwise,
the losing registrar unsets the authorization information when
the TTL expires, as defined in expires; see Section 5.2.

The following sections outline the practices of the EPP commands and
responses between the registrar and the registry that supports secure
authorization information for transfer.

5.1. Create <Create> Command

For a create <create> command, the registry MUST allow for the passing of an
empty authorization information value and MAY disallow for the passing of
a non-empty authorization information value. By having an empty
authorization information value on create, the object is initially
not involved in the transfer process. Any EPP object extension that
supports setting the authorization information with a an
"eppcom:pwAuthInfoType" element can have pass an empty authorization
information value passed. value. Examples of such extensions are found in
[RFC5731] and [RFC5733].

Example of passing an empty authorization information value in an
[RFC5731] a
domain name create command: <create> command [RFC5731]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <create>
C: <domain:create
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example.com</domain:name>
C: <domain:authInfo>
C: <domain:pw/>
C: </domain:authInfo>
C: </domain:create>
C: </create>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>

Example of passing an empty authorization information value in an
[RFC5733] a
contact create command: <create> command [RFC5733]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <create>
C: <contact:create
C: xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
C: <contact:id>sh8013</contact:id>
C: <contact:postalInfo type="int">
C: <contact:name>John Doe</contact:name>
C: <contact:addr>
C: <contact:city>Dulles</contact:city>
C: <contact:cc>US</contact:cc>
C: </contact:addr>
C: </contact:postalInfo>
C: <contact:email>jdoe@example.com</contact:email>
C: <contact:authInfo>
C: <contact:pw/>
C: </contact:authInfo>
C: </contact:create>
C: </create>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>

5.2. Update <Update> Command

For an update <update> command, the registry MUST allow for the setting and
unsetting of the authorization information. The registrar sets the
authorization information by first generating a strong, random
authorization information value, based on the information provided in
Section 4.1, and setting it in the registry in the update <update> command.
The importance of generating strong authorization information values
cannot be overstated: secure transfers are very important to the
Internet to mitigate damage in the form of theft, fraud, and other
abuse. It is critical that registrars only use strong, randomly
generated authorization information values.

Because of this, registries may validate the randomness of the
authorization information based on the length and character set
required by the registry. For registry -- for example, validating that an
authorization value contains a combination of upper-case, lower-case, uppercase, lowercase,
and non-
alphanumeric characters, non-alphanumeric characters in an attempt to assess the strength
of the
value, value and return returning an EPP error result of 2202 ("Invalid
authorization information") [RFC5730] if the check fails.

Such checks are, by their nature, heuristic and imperfect, and may
identify well-chosen authorization information values as being not
sufficiently strong. Registrars, therefore, must be prepared for an
error response of 2202, "Invalid authorization information", 2202 and respond by generating a new value and
trying again, possibly more than once.

Often, the registrar has the "clientTransferProhibited" status set,
so to start the transfer process, the "clientTransferProhibited"
status needs to be removed, and the strong, random authorization
information value needs to be set. The registrar MUST define a time-
to-live (TTL), TTL,
as defined described in Section 4.2, where and if the TTL expires expires, the registrar
will unset the authorization information.

Example of removing the "clientTransferProhibited" status and setting
the authorization information in an [RFC5731] a domain name update
command: <update> command
[RFC5731]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example.com</domain:name>
C: <domain:rem>
C: <domain:status s="clientTransferProhibited"/>
C: </domain:rem>
C: <domain:chg>
C: <domain:authInfo>
C: <domain:pw>LuQ7Bu@w9?%+_HK3cayg$55$LSft3MPP
C: </domain:pw>
C: </domain:authInfo>
C: </domain:chg>
C: </domain:update>
C: </update>
C: <clTRID>ABC-12345-XYZ</clTRID>
C: </command>
C:</epp>

When the registrar-defined TTL expires, the sponsoring registrar MUST
cancel the transfer process by unsetting the authorization
information value and MAY add back statuses like the
"clientTransferProbited"
"clientTransferProhibited" status. Any EPP object extension that
supports setting the authorization information with a an
"eppcom:pwAuthInfoType" element, element can have pass an empty authorization
information value passed. value. Examples of such extensions are found in
[RFC5731] and [RFC5733]. Setting an empty authorization information
value unsets the authorization information. [RFC5731] supports an
explicit mechanism of unsetting the authorization information, by
passing the <domain:null> authorization information value. The
registry MUST support unsetting the authorization information by
accepting an empty authorization information value and accepting an
explicit unset element if it is supported by the object extension.

Example of adding the "clientTransferProhibited" status and unsetting
the authorization information explicitly in an [RFC5731] a domain name
update command: <update>
command [RFC5731]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example.com</domain:name>
C: <domain:add>
C: <domain:status s="clientTransferProhibited"/>
C: </domain:add>
C: <domain:chg>
C: <domain:authInfo>
C: <domain:null/>
C: </domain:authInfo>
C: </domain:chg>
C: </domain:update>
C: </update>
C: <clTRID>ABC-12345-XYZ</clTRID>
C: </command>
C:</epp>

Example of unsetting the authorization information with an empty
authorization information value in an [RFC5731] a domain name update
command: <update> command
[RFC5731]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <update>
C: <domain:update
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example.com</domain:name>
C: <domain:add>
C: <domain:status s="clientTransferProhibited"/>
C: </domain:add>
C: <domain:chg>
C: <domain:authInfo>
C: <domain:pw/>
C: </domain:authInfo>
C: </domain:chg>
C: </domain:update>
C: </update>
C: <clTRID>ABC-12345-XYZ</clTRID>
C: </command>
C:</epp>

Example of unsetting the authorization information with an empty
authorization information value in an [RFC5733] a contact update
command: <update> command
[RFC5733]:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <update>
C: <contact:update
C: xmlns:contact="urn:ietf:params:xml:ns:contact-1.0">
C: <contact:id>sh8013</contact:id>
C: <contact:chg>
C: <contact:authInfo>
C: <contact:pw/>
C: </contact:authInfo>
C: </contact:chg>
C: </contact:update>
C: </update>
C: <clTRID>ABC-12345-XYZ</clTRID>
C: </command>
C:</epp>

5.3. Info <Info> Command and Response

For an info <info> command, the registry MUST allow for the passing of a
non-empty non-
empty authorization information value for verification. The gaining
registrar can pre-verify the authorization information provided by
the registrant prior to submitting the transfer request with the use
of the info <info> command. The registry compares the hash of the passed
authorization information with the hashed authorization information
value stored for the object. When the authorization information is
not set or the passed authorization information does not match the
previously set value, the registry MUST return an EPP error result
code of 2202 [RFC5730].

Example of passing a non-empty authorization information value in an
[RFC5731] a
domain name info <info> command [RFC5731] to verify the authorization
information value:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <info>
C: <domain:info
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example.com</domain:name>
C: <domain:authInfo>
C: <domain:pw>LuQ7Bu@w9?%+_HK3cayg$55$LSft3MPP
C: </domain:pw>
C: </domain:authInfo>
C: </domain:info>
C: </info>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>

The info response in object extensions, such as those defined in
[RFC5731] and [RFC5733], MUST NOT include the optional authorization
information element with a non-empty authorization value. The
authorization information is stored as a hash in the registry, so
returning the
plain text plain-text authorization information is not possible,
unless a valid
plain text plain-text authorization information is passed in the info
<info> command. The registry MUST NOT return any indication of
whether the authorization information is set or unset to the non-sponsoring non-
sponsoring registrar by not returning the authorization information
element in the response. The registry MAY return an indication to
the sponsoring registrar that the authorization information is set by
using an empty authorization information value. The registry MAY
return an indication to the sponsoring registrar that the
authorization information is unset by not returning the authorization
information element.

Example of returning an empty authorization information value in an
[RFC5731] a
domain name info response [RFC5731] to indicate to the sponsoring
registrar that the authorization information is set:

S:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
S:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
S: <response>
S: <result code="1000">
S: <msg>Command completed successfully</msg>
S: </result>
S: <resData>
S: <domain:infData
S: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
S: <domain:name>example.com</domain:name>
S: <domain:roid>EXAMPLE1-REP</domain:roid>
S: <domain:status s="ok"/>
S: <domain:clID>ClientX</domain:clID>
S: <domain:authInfo>
S: <domain:pw/>
S: </domain:authInfo>
S: </domain:infData>
S: </resData>
S: <trID>
S: <clTRID>ABC-12345</clTRID>
S: <svTRID>54322-XYZ</svTRID>
S: </trID>
S: </response>
S:</epp>

5.4. Transfer <Transfer> Request Command

For a Transfer Request Command, <transfer> request command, the registry MUST allow for the passing
of a non-empty authorization information value to authorize a
transfer. The registry compares the hash of the passed authorization
information with the hashed authorization information value stored
for the object. When the authorization information is not set or the
passed authorization information does not match the previously set
value, the registry MUST return an EPP error result code of 2202
[RFC5730]. Whether the transfer occurs immediately or is pending is
up to server policy. When the transfer occurs immediately, the
registry MUST return the EPP success result code of 1000 ("Command
completed successfully") [RFC5730], and when the transfer is pending,
the registry MUST return the EPP success result code of 1001. 1001
("Command completed successfully; action pending"). The losing
registrar MUST be informed of a successful transfer request using an
EPP poll <poll> message.

Example of passing a non-empty authorization information value in an
[RFC5731] a
domain name transfer <transfer> request command [RFC5731] to authorize the
transfer:

C:<?xml version="1.0" encoding="UTF-8" standalone="no"?>
C:<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
C: <command>
C: <transfer op="request">
C: <domain:transfer
C: xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
C: <domain:name>example1.com</domain:name>
C: <domain:authInfo>
C: <domain:pw>LuQ7Bu@w9?%+_HK3cayg$55$LSft3MPP
C: </domain:pw>
C: </domain:authInfo>
C: </domain:transfer>
C: </transfer>
C: <clTRID>ABC-12345</clTRID>
C: </command>
C:</epp>

Upon successful completion of the transfer, the registry MUST
automatically unset the authorization information. If the transfer
request is not submitted within the time-to-live (TTL) TTL (Section 4.2) or the transfer
is cancelled canceled or rejected, the registrar MUST unset the authorization information
information, as defined described in Section 5.2.

6. Transition Considerations

The goal of the transition considerations to the practice defined in
this document, referred to as the Secure Authorization Information
Model, is to minimize the impact
to the registrars in supporting the Secure Authorization Information
Model defined in this document by supporting incremental steps of adoption. transition
steps. The transition steps are dependent on the starting point of
the registry. Registries may have different starting points, since
some of the elements of the Secure Authorization Information Model
may have already been implemented. The considerations assume a
starting point, referred to as the
Classic "Classic Authorization Information Model, that have
Model", which incorporates the following steps in the for management of the
authorization information for transfers:

1. Registrant The registrant requests to register the object with the
registrar.
Registrar The registrar sends the create <create> command, with a non-empty non-
empty authorization information value, to the registry. The
registry stores the authorization information as an encrypted
value and requires a non-empty authorization information value
for the life of the object. The registrar may store the long-lived long-
lived authorization information.

2. At the time of transfer, Registrant the registrant requests from the losing
registrar the authorization information to provide to the gaining
registrar.

3. Losing The losing registrar retrieves the locally stored authorization
information or queries the registry for authorization information
using the info <info> command, and provides it to the registrant. If
the registry is queried, the authorization information is
decrypted and the plain text plain-text authorization information is
returned in the info response to the registrar.

4. Registrant The registrant provides the authorization information value to
the gaining registrar.

5. Gaining The gaining registrar optionally verifies the authorization
information with the info <info> command to the registry, by passing
the authorization information in the info <info> command to the
registry.

6. Gaining The gaining registrar sends the transfer request with the
authorization information to the registry. The registry will
decrypt the stored authorization information to compare to the
passed authorization information.

7. If the transfer successfully completes, completes successfully, the authorization
information is not touched by the registry and may be updated by
the gaining registrar using the update <update> command. If the
transfer is cancelled canceled or rejected, the losing registrar may reset
the authorization information using the update <update> command.

The gaps between the Classic Authorization Information Model and the
Secure Authorization Information Model include: include the following:

1. Registry requirement for a non-empty authorization information
value on create and for the life of the object versus the
authorization information not being set on create and only being
set when a transfer is in process.

2. Registry not allowing the authorization information to be unset
versus supporting providing support for unsetting the authorization to be unset
information in the update <update> command.

3. Registry storing the authorization information as an encrypted
value versus as a hashed value.

4. Registry support for returning the authorization information
versus not returning the authorization information in the info
response.

5. Registry not touching the authorization information versus the
registry automatically unsetting the authorization information
upon a successful transfer.

6. Registry may validate possibly validating a shorter authorization information
value using password complexity rules versus validating the
randomness of a longer authorization information value that meets
the required bits of entropy.

The transition can be handled in the three phases defined in the sub-
sections Section
Sections 6.1, Section 6.2, Section and 6.3.

6.1. Transition Phase 1 - Features

The goal of the "Transition Phase 1 - Features" is to implement the
needed features in EPP so that the registrar can optionally implement
the Secure Authorization Information Model. The features to
implement are broken out by the command commands and responses below:

Create

<Create> Command: Change the create <create> command to make the
authorization information optional, by allowing both a non-empty
value and an empty value. This enables a registrar to optionally
create objects without an authorization information value, as defined
described in Section 5.1.
Update

<Update> Command: Change the update <update> command to allow unsetting the
authorization information, as defined described in Section 5.2. This
enables the registrar to optionally unset the authorization
information when the TTL expires or when the transfer is cancelled canceled
or rejected.

Transfer Approve Command and Transfer Auto-Approve: Change the
transfer approve command and the transfer auto-approve to
automatically unset the authorization information. This sets the
default state of the object to not have the authorization
information set. The registrar implementing the Secure
Authorization Information Model will not set the authorization
information for an inbound transfer transfer, and the registrar
implementing the Classic Authorization Information Model will set
the new authorization information upon the a successful transfer.

Info Response: Change the info <info> command to not return the
authorization information in the info response, as defined described in
Section 5.3. This sets up the implementation of "Transition Phase
2 - Storage", Storage" (Section 6.2), since the dependency in on returning the
authorization information in the info response will be removed.
This feature is the only one that is not an optional change to the registrar that
has the potential of breaking
registrar, and this change could potentially break the client, so
it's recommended that the registry provide notice of the change.
Info

<Info> Command and Transfer Request: Change the info <info> command and
the transfer request to ensure that a registrar cannot get an
indication that the authorization information is set or not set by
returning the EPP error result code of 2202 when comparing a
passed authorization to a non-matching set authorization
information value or an unset value.

6.2. Transition Phase 2 - Storage

The goal of the "Transition Phase 2 - Storage" is to transition the
registry to use hashed authorization information instead of encrypted
authorization information. There is no direct impact to on the
registrars, since the only visible indication that the authorization
information has been hashed is by not returning that the set authorization information
is not returned in the info response, which is as addressed in Transition "Transition
Phase 1 - Features Features" (Section 6.1). There are three steps to
transition Transitioning the authorization
information storage, which includes: storage includes the following three steps:

Hash New Authorization Information Values: Change the create <create>
command and the update <update> command to hash instead of encrypting rather than encrypt the
authorization information.
Supporting Comparing Against

Support Comparison against Encrypted and or Hashed Authorization
Information: Change the info <info> command and the transfer <transfer> request
command to be able to compare a passed authorization information
value with either a hashed or encrypted authorization information
value. This requires that the stored values are be self-identifying
as being in hashed or encrypted form.

Hash Existing Encrypted Authorization Information Values: Convert
the encrypted authorization information values stored in the
registry database to hashed values. The This update is will not a be
visible
change to the registrar. The conversion can be done over a
period of time time, depending on registry policy.

6.3. Transition Phase 3 - Enforcement

The goal of the "Transition Phase 3 - Enforcement" is to complete the
implementation of the "Secure Secure Authorization Information Model", Model, by
enforcing the following:

Disallow Authorization Information on Create <Create> Command: Change the
create
<create> command to not allow for the passing of a non-empty
authorization information value. This behavior has the potential
of breaking could potentially
break the client, so it's recommended that the registry provide
notice of the this change.

Validate the Strong Random Authorization Information: Change the
validation of the authorization information in the update <update>
command to ensure at least 128 bits of entropy.

7. IANA Considerations

7.1. XML Namespace

This document uses URNs to describe XML namespaces conforming to a the
registry mechanism described in [RFC3688]. The IANA has assigned the
following URI
assignment is requested of IANA:

Registration request for in the "ns" subregistry within the "IETF XML Registry"
for secure authorization information for the transfer namespace:

URI: urn:ietf:params:xml:ns:epp:secure-authinfo-transfer-1.0
Registrant Contact: IESG
XML: None. Namespace URIs do not represent an XML specification.

7.2. EPP Extension Registry

The

IANA has registered the EPP operational practice described in this
document should be
registered by the IANA in the EPP Extension Registry described "Extensions for the Extensible Provisioning Protocol
(EPP)" registry as defined in [RFC7451]. The details of the
registration are as follows:

Name of Extension: "Extensible Provisioning Protocol (EPP) Secure
Authorization Information for Transfer"
Document status: Standards Track
Reference: (insert reference to RFC version of this document) 9154
Registrant Name and Email Address: IESG, <iesg@ietf.org> IESG (iesg@ietf.org)
TLDs: Any
IPR Disclosure: None
Status: Active
Notes: None

8. Implementation Status

Note to RFC Editor: Please remove this section and the reference to
RFC 7942 [RFC7942] before publication.

This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
[RFC7942]. The description of implementations in this section is
intended to assist the IETF in its decision processes in progressing
drafts to RFCs. Please note that the listing of any individual
implementation here does not imply endorsement by the IETF.
Furthermore, no effort has been spent to verify the information
presented here that was supplied by IETF contributors. This is not
intended as, and must not be construed to be, a catalog of available
implementations or their features. Readers are advised to note that
other implementations may exist.

According to RFC 7942 [RFC7942], "this will allow reviewers and
working groups to assign due consideration to documents that have the
benefit of running code, which may serve as evidence of valuable
experimentation and feedback that have made the implemented protocols
more mature. It is up to the individual working groups to use this
information as they see fit".

8.1. Verisign EPP SDK

Organization: Verisign Inc.

Name: Verisign EPP SDK

Description: The Verisign EPP SDK includes both a full client
implementation and a full server stub implementation of draft-ietf-
regext-secure-authinfo-transfer.

Level of maturity: Development

Coverage: All aspects of the protocol are implemented.

Licensing: GNU Lesser General Public License

Contact: jgould@verisign.com

URL: https://www.verisign.com/en_US/channel-resources/domain-
registry-products/epp-sdks

8.2. RegistryEngine EPP Service

Organization: CentralNic

Name: RegistryEngine EPP Service

Description: Generic high-volume EPP service for gTLDs, ccTLDs and
SLDs

Level of maturity: Deployed in CentralNic's production environment as
well as two other gTLD registry systems, and two ccTLD registry
systems.

Coverage: Authorization Information is "write only" in that the
registrars can set the Authorization Information, but not get the
Authorization Information in the Info Response.

Licensing: Proprietary In-House software

Contact: epp@centralnic.com
URL: https://www.centralnic.com

9. Security Considerations

Section 4.1 defines the use of a secure random value for the
generation of the authorization information. The client SHOULD choose a
length and set of characters that results result in at least 128 bits of
entropy.

Section 4.2 defines the use of an authorization information Time-To-
Live (TTL). TTL. The
registrar SHOULD only set the authorization information during the
transfer process by the server support for setting the authorization information at the
start of the transfer process and unsetting the authorization information.
information at the end of the transfer process. The TTL value is
left up to registrar policy policy, and the sponsoring registrar MUST inform
the registrant of the TTL when providing the authorization
information to the registrant.

Section 4.3 defines the storage and transport of authorization
information. The losing registrar MUST NOT store the authorization
information and the gaining registrar MUST only store the
authorization information as a "transient" value during the transfer
process, where the authorization information MUST NOT be stored after
the end of the transfer process. The registry MUST store the
authorization information using a one-way cryptographic hash of at
least 256 bits and with a per-authorization information random salt, salt
with at least 128 bits. All communication that includes the
authorization information MUST be over an encrypted channel. The
plain text
plain-text authorization information MUST NOT be written to any logs
by the registrar or the registry.

Section 4.4 defines the matching of the authorization information
values. The registry stores an unset authorization information value
as a NULL (undefined) value to ensure that an empty input
authorization information value never matches it. The method used to
define a NULL (undefined) value is database specific.

10. Acknowledgements

The authors wish to thank the following persons for their feedback
and suggestions: Michael Bauland, Martin Casanova, Scott Hollenbeck,
Benjamin Kaduk, Jody Kolker, Barry Leiba, Patrick Mevzek, Matthew
Pozun, Srikanth Veeramachaneni, and Ulrich Wisser.

11.

9. References

11.1.

9.1. Normative References

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

[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.

[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<https://www.rfc-editor.org/info/rfc4086>.

[RFC5730] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
<https://www.rfc-editor.org/info/rfc5730>.

[RFC5731] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
Domain Name Mapping", STD 69, RFC 5731,
DOI 10.17487/RFC5731, August 2009,
<https://www.rfc-editor.org/info/rfc5731>.

[RFC5733] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
Contact Mapping", STD 69, RFC 5733, DOI 10.17487/RFC5733,
August 2009, <https://www.rfc-editor.org/info/rfc5733>.

[RFC5734] Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
Transport over TCP", STD 69, RFC 5734,
DOI 10.17487/RFC5734, August 2009,
<https://www.rfc-editor.org/info/rfc5734>.

[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.

[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.

[RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/info/rfc8499>.

11.2.

[W3C.REC-xml-20081126]
Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", World Wide Web Consortium Recommendation REC-
xml-20081126, November 2008,
<https://www.w3.org/TR/2008/REC-xml-20081126>.

9.2. Informative References

[FIPS-140-2]
National Institute of Standards and Technology, U.S.
Department of Commerce, "NIST Federal Information
Processing Standards (FIPS) Publication 140-2",
DOI 10.6028/NIST.FIPS.140-2, May 2001,
<https://csrc.nist.gov/publications/detail/fips/140/2/
final>.

[FIPS-180-4]
National Institute of Standards and Technology, U.S.
Department of Commerce, "Secure Hash Standard, NIST
Federal Information Processing Standards (FIPS)
Publication 180-4", DOI 10.6028/NIST.FIPS.180-4, August
2015,
<https://csrc.nist.gov/publications/detail/fips/180/4/
final>.

[RFC7451] Hollenbeck, S., "Extension Registry for the Extensible
Provisioning Protocol", RFC 7451, DOI 10.17487/RFC7451,
February 2015, <https://www.rfc-editor.org/info/rfc7451>.

Appendix A. Change History

A.1. Change from 00 to 01

1. Filled in the "Implementation Status" section with the inclusion
of the "Verisign EPP SDK" and "RegistryEngine EPP Service"
implementations.
2. Made small wording corrections based on private feedback.
3. Added content to the "Acknowledgements" section.

A.2. Change from 01

Acknowledgements

The authors wish to 02

1. Revised thank the language used following persons for the storage of the authorization
information based on the feedback from Patrick Mevzek and Jody
Kolker.

A.3. Change from 02 to 03

1. Updates based on the their feedback from the interim REGEXT meeting
held at ICANN-66:
1. Section 3.3, include a reference to the hash algorithm to
use. Broke the requirements into a list
and included a the
reference the text ', with at least a 256-bit hash function,
such as SHA-256'.
2. Add a Transition Considerations section to cover the
transition from the classic authorization information
security model in the EPP RFCs to the model defined in the
document.

3. Add a statement to the Introduction that elements of the
practice can be used for purposes other than transfer, but
with a caveat.
2. Updates based on the review by suggestions: Michael Bauland, that include:
1. In section 2, change 'there are three actors' to 'there are
three types of actors' to cover the case with transfers that
has two registrar actors (losing and gaining).
2. In section 3.1, change the equations equals to be
approximately equal by using '=~' instead of '=', where
applicable.
3. In section 3.3, change 'MUST be over an encrypted channel,
such as RFC5734' to 'MUST be over an encrypted channel, such
as defined in RFC5734'.
4. In section 4.1, remove the optional RFC 5733 elements from
the contact create, which includes the <contact:voice>,
<contact:fax>, <contact:disclose>, <contact:org>,
<contact:street>, <contact:sp>, and <contact:cc> elements.
5. In section 4.2, changed 'Example of unsetting the
authorization information explicitly in an [RFC5731] domain
name update command.' to 'Example of adding the
"clientTransferProhibited" status and unsetting the
authorization information explicitly in an [RFC5731] domain
name update command.'
6. In section 4.3, cover a corner case of the ability to return
the authorization information when it's passed in the info
command.
7. In section 4.4, change 'If the transfer does not complete
within the time-to-live (TTL)' to 'If the transfer is not
initiated within the time-to-live (TTL)', since the TTL is
the time between setting the authorization information and
when it's successfully used in a transfer request. Added the
case of unsetting the authorization information when the
transfer is cancelled or rejected.
3. Updates based on the authorization information messages by Martin
Casanova on the REGEXT mailing list, that include:
1. Added section 3.4 'Authorization Information Matching' to
clarify how the authorization information is matched, when
there is set and unset authorization information in the
database and empty and non-empty authorization information
passed in the info and transfer commands.
2. Added support for signaling that the authorization
information is set or unset to the sponsoring registrar with
the inclusion of an empty authorization information element
in the response to indicate that the authorization
information is set and the exclusion of the authorization
information element in the response to indicate that the
authorization information is unset.

4. Made the capitalization of command and response references
consistent by uppercasing section and item titles and lowercasing
references elsewhere.

A.4. Change from 03 to REGEXT 00

1. Changed to regext working group draft by changing draft-gould-
regext-secure-authinfo-transfer to draft-ietf-regext-secure-
authinfo-transfer.

A.5. Change from REGEXT 00 to REGEXT 01

1. Added the "Signaling Client and Server Support" section to
describe the mechanism to signal support for the BCP by the
client and the server.
2. Added the "IANA Considerations" section with the registration of
the secure authorization for transfer XML namespace and the
registration of the EPP Best Current Practice (BCP) in the EPP
Extension Registry.

A.6. Change from REGEXT 01 to REGEXT 02

1. Added inclusion of random salt for the hashed authorization
information, based on feedback from Ulrich Wisser.
2. Added clarification that the representation of a NULL (undefined)
value is dependent on the type of database, based on feedback
from Patrick Mevzek.
3. Filled in the Security Considerations section.

A.7. Change from REGEXT 02 to REGEXT 03

1. Updated the XML namespace to urn:ietf:params:xml:ns:epp:secure-
authinfo-transfer-1.0, which removed bcp from the namespace and
bumped the version from 0.1 and 1.0. Inclusion of bcp in the XML
namespace was discussed at the REGEXT interim meeting.
2. Replaced Auhtorization with Authorization based on a review by Casanova, Scott Hollenbeck,
Benjamin Kaduk, Jody Kolker.

A.8. Change from REGEXT 03 to REGEXT 04

1. Converted from xml2rfc v2 to v3.
2. Updated Acknowledgements to match the approach taken by the RFC
Editor with draft-ietf-regext-login-security.
3. Changed from Best Current Practice (BCP) to Standards Track based
on mailing list discussion.

A.9. Change from REGEXT 04 to REGEXT 05
1. Fixed IDNITS issues, including moving RFC7451 to Informative
References section.

A.10. Change from REGEXT 05 to REGEXT 06

Updates based on the Barry Leiba (AD) feedback:

1. Simplified the abstract based on the proposal provided.
2. In the Introduction, split the first paragraph by starting a new
paragraph at "This document".
3. In section 1.1, updated to use the new BCP 14 boilerplate and
add a normative reference to RFC 8174.
4. In section 4, Updated the phrasing to "For the authorization
information to be secure it must be generated using a strong
random value and have a short time-to-live (TTL).".
5. In section 4.1, removed the first two unnecessary calculations
and condensed the introduction of the section.
6. In section 4.1, added the use of the normative SHOULD for use of
at least 128 bits of entropy.
7. Added an informative reference to FIPS 180-4 for the SHA-256
references.
8. Normalized the way that the "empty and non-empty authorization
information values" are referenced, which a few exceptions.
9. In section 4, revised the first sentence to explicitly reference
the use of the <domain:pw> and <contact:pw> elements for
password-based authorization information.
10. In section 4.4, revised the language associated with the storage
of the authorization information to be cleaner.
11. In section 4.4, added "set" in the sentence "An empty input
authorization information value MUST NOT match any set
authorization information value."
12. In section 5.1 and 5.2, clarified the references to RFC5731 and
RFC5733 as examples of object extensions that use the
"eppcom:pwAuthInfoType" element.
13. In section 5.2, updated language for the validation of the
randomness of the authorization information, based on an offline
review by Kolker, Barry Leiba, Benjamin Kaduk, and Roman Danyliw.
14. In section 9, changed "49 bits of entropy" to "128 bits of
entropy".

In section 3, replaced the reference to BCP with operational
practice, since the draft is not defined as a BCP.

A.11. Change from REGEXT 06 to REGEXT 07

1. Updates based on the Lars Eggert feedback:

1. Updated Section 1, Paragraph 4 to read "The operational
practice will require the client to not store the
authorization information and".
2. Updated each of the example references to end with a colon
instead of a period.
3. Updated Section 1, Paragraph 3 to read "provide secure
authorization information used for transfers."
4. Updated Section 3, Paragraph 3 to read "extension services
can expect".
5. Updated Section 4, Paragraph 2 to read "authorization
information to be secure, it must".
6. Updated Section 4.2, Paragraph 2 to read "authorization
information by the sponsoring registrar, the".
7. Updated Section 4.2, Paragraph 2 to read "proprietary
registrar-specific criteria, which".
8. Updated Section 4.3, Paragraph 3 to read "256-bit hash
function, such as SHA-256".
9. Updated Section 4.3, Paragraph 3 to read "a NULL (undefined)
value".
10. Updated Section 5, Paragraph 2 to read "To secure the
transfer process using secure authorization".
11. Updated Section 5.2, Paragraph 6 to read "Often, the
registrar has the "clientTransferProhibited" status set".
12. Updated Section 5.2, Paragraph 9 to read "MUST cancel cancel
the transfer process by unsetting the authorization
information value and MAY add back statuses".
13. Updated Section 5.2, Paragraph 9 to read
""eppcom:pwAuthInfoType" element can have".

2. Updated the first sentence of the abstract and introduction based
on the Rob Wilton feedback to help non-EPP readers on the what
and the who for transfers.

3. Removed the duplicate first paragraph of section 5.2 based on
feedback from Francesca Palombini.

4. Updates based on the Benjamin Kaduk feedback:

1. Added the second paragraph in the Introduction to provide
high-level motivation for the work.
2. Updated Section 1, changed "in any way" to "in any
substantial way".
3. Updated Section 1 by adding the sentence "All of these
features are compatible with the EPP RFCs, though not
mandatory to implement." for the "Short-Lived Authorization
Information".

4. Updated the description of "Short-Lived Authorization
Information" in Section 1 to reference section 2.6 of
RFC5731 and change in nature of the authorization
information.
5. Updated Section 4.1, Paragraph 1 and 2 were merged with
modified language proposed by Benjamin Kaduk, which included
removing the reference to RFC4086 for length and entropy.
6. Updated rule #1 of Section 4.1 to add a second clarifying
sentence for what is meant by input authorization
information.
7. Updated Section 4.1 by replacing the last paragraph "The
strength of the random..." with a revised version.
8. Updated "retrieves the stored authorization information
locally" with "retrieves the locally stored authorization
information".
9. Updated Section 6.1 to include the recommendation that the
registry provide notice of the Info Response change.
10. Updated Section 6.2 to include the sentence "This requires
that the stored values are self-identifying as being in
hashed or encrypted form" for the "Supporting Comparing
Against Encrypted and Hashed Authorization Information"
step.
11. Updated Section 6.3 to include the recommendation that the
registry provide notice of the Create Command change.
12. Updated "written to any logs by the registrar or the
registry" to "written to any logs by a registrar or the
registry" to cover both the losing and the gaining
registrar.
13. Updated references to "with a random salt" to "with a per-
authorization information random salt, with at least 128
bits" to address sharing of salts and the size of the salts.
14. Updated the first paragraph of Section 9 to remove the
reference to defining a server policy for the length Patrick Mevzek, Matthew
Pozun, Srikanth Veeramachaneni, and set
of characters that are included in the randomization to
target the target entropy level.
15. Updated Section 9 by removing the sentence "A random number
generator (RNG) is preferable over the use of a pseudorandom
number generator (PRNG) when creating the authorization
information value."
16. Changed FIPS-140-2 from a normative reference to an
informative reference. Ulrich Wisser.

Authors' Addresses

James Gould
VeriSign,
Verisign, Inc.
12061 Bluemont Way
Reston, VA 20190
United States of America

Email: jgould@verisign.com
URI: http://www.verisign.com https://www.verisign.com

Richard Wilhelm
VeriSign,
Verisign, Inc.
12061 Bluemont Way
Reston, VA 20190
United States of America

Email: rwilhelm@verisign.com 4rickwilhelm@gmail.com
URI: http://www.verisign.com https://www.verisign.com