draft-ietf-ipsecme-rfc4307bis-03.txt   draft-ietf-ipsecme-rfc4307bis-04.txt 
Network Working Group Y. Nir Network Working Group Y. Nir
Internet-Draft Check Point Internet-Draft Check Point
Intended status: Standards Track T. Kivinen Intended status: Standards Track T. Kivinen
Expires: August 13, 2016 INSIDE Secure Expires: September 17, 2016 INSIDE Secure
P. Wouters P. Wouters
Red Hat Red Hat
D. Migault D. Migault
Ericsson Ericsson
February 10, 2016 March 16, 2016
Algorithm Implementation Requirements and Usage Guidance for IKEv2 Algorithm Implementation Requirements and Usage Guidance for IKEv2
draft-ietf-ipsecme-rfc4307bis-03 draft-ietf-ipsecme-rfc4307bis-04
Abstract Abstract
The IPsec series of protocols makes use of various cryptographic The IPsec series of protocols makes use of various cryptographic
algorithms in order to provide security services. The Internet Key algorithms in order to provide security services. The Internet Key
Exchange protocol provides a mechanism to negotiate which algorithms Exchange (IKE) protocol is used to negotiate the IPsec Security
should be used in any given Security Association. To ensure Association (IPsec SA) parameters, such as which algorithms should be
interoperability between different implementations, it is necessary used. To ensure interoperability between different implementations,
to specify a set of algorithm implementation requirements and Usage it is necessary to specify a set of algorithm implementation
guidance to ensure that there is at least one algorithm that all requirements and usage guidance to ensure that there is at least one
implementations will have available. This document defines the algorithm that all implementations support. This document defines
current algorithm implementation requirements and usage guidance of the current algorithm implementation requirements and usage guidance
IKEv2. This document does not update the algorithms used for packet for IKEv2. This document does not update the algorithms used for
encryption using IPsec Encapsulated Security Payload (ESP) packet encryption using IPsec Encapsulated Security Payload (ESP)
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 13, 2016. This Internet-Draft will expire on September 17, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
skipping to change at page 2, line 35 skipping to change at page 2, line 32
1.2. Updating Algorithm Requirement Levels . . . . . . . . . . 3 1.2. Updating Algorithm Requirement Levels . . . . . . . . . . 3
1.3. Document Audience . . . . . . . . . . . . . . . . . . . . 4 1.3. Document Audience . . . . . . . . . . . . . . . . . . . . 4
2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . 4
3. Algorithm Selection . . . . . . . . . . . . . . . . . . . . . 5 3. Algorithm Selection . . . . . . . . . . . . . . . . . . . . . 5
3.1. Type 1 - IKEv2 Encryption Algorithm Transforms . . . . . 5 3.1. Type 1 - IKEv2 Encryption Algorithm Transforms . . . . . 5
3.2. Type 2 - IKEv2 Pseudo-random Function Transforms . . . . 6 3.2. Type 2 - IKEv2 Pseudo-random Function Transforms . . . . 6
3.3. Type 3 - IKEv2 Integrity Algorithm Transforms . . . . . . 7 3.3. Type 3 - IKEv2 Integrity Algorithm Transforms . . . . . . 7
3.4. Type 4 - IKEv2 Diffie-Hellman Group Transforms . . . . . 8 3.4. Type 4 - IKEv2 Diffie-Hellman Group Transforms . . . . . 8
4. IKEv2 Authentication . . . . . . . . . . . . . . . . . . . . 10 4. IKEv2 Authentication . . . . . . . . . . . . . . . . . . . . 10
4.1. IKEv2 Authentication Method . . . . . . . . . . . . . . . 10 4.1. IKEv2 Authentication Method . . . . . . . . . . . . . . . 10
4.2. Digital Signature Recommendation . . . . . . . . . . . . 11 4.1.1. Recommendations for RSA key length . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 4.2. Digital Signature Recommendations . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
8.1. Normative References . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.2. Informative References . . . . . . . . . . . . . . . . . 13 8.1. Normative References . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 8.2. Informative References . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
The Internet Key Exchange protocol [RFC7296] is used to negotiate the The Internet Key Exchange (IKE) protocol [RFC7296] is used to
IPsec parameters, such as encryption algorithms and keys, for negotiate the parameters of the IPsec SA, such as the encryption and
protected communications between two endpoints. The IKEv2 protocol authentication algorithms and the keys for the protected
itself is also protected by encryption, which is also negotiated communications between the two endpoints. The IKE protocol itself is
between the two endpoints. Negotiation is performed by IKEv2 itself. also protected by encryption which is negotiated between the two
This document describes the encryption parameters of the IKE endpoints using IKE. Different implementations of IKE may negotiate
protocol, not the encryption parameters of the ESP (IPsec) protocol. different algorithms based on their individual local policy. To
ensure interoperability, a set of "mandatory-to-implement" IKE
encryption algorithms is defined.
Different implementations of IKEv2 may negotiate different encryption This document describes the parameters of the IKE protocol. It does
algorithms based on their individual local policy. To ensure not describe the cryptographic parameters of the AH or ESP protocols.
interoperability, a set of "mandatory-to-implement" IKEv2 encryption
algorithms is defined.
1.1. Updating Algorithm Implementation Requirements and Usage Guidance 1.1. Updating Algorithm Implementation Requirements and Usage Guidance
The field of cryptography evolves continiously. New stronger The field of cryptography evolves continuously. New stronger
algorithms appear and existing algorithms are found to be less secure algorithms appear and existing algorithms are found to be less secure
then originally thought. Therefore, algorithm implementation then originally thought. Therefore, algorithm implementation
requirements and usage guidance need to be updated from time to time requirements and usage guidance need to be updated from time to time
to reflect the new reality. The choices for algorithms must be to reflect the new reality. The choices for algorithms must be
conservative to minimize the risk of algorithm compromised. conservative to minimize the risk of algorithm compromise.
Algorithms need to be suitable for a wide variety of CPU Algorithms need to be suitable for a wide variety of CPU
architectures and device deployments ranging from high end bulk architectures and device deployments ranging from high end bulk
encryption devices to small low-power IoT devices. encryption devices to small low-power IoT devices.
The algorithm implementation requirements and usage guidance may need The algorithm implementation requirements and usage guidance may need
to change over time to adapt to the changing world. For this reason, to change over time to adapt to the changing world. For this reason,
the selection of mandatory-to-implement algorithms was removed from the selection of mandatory-to-implement algorithms was removed from
the main IKEv2 specification and placed in this document. the main IKEv2 specification and placed in this document.
1.2. Updating Algorithm Requirement Levels 1.2. Updating Algorithm Requirement Levels
Ideally, the mandatory-to-implement algorithm of tomorrow should The mandatory-to-implement algorithm of tomorrow should already be
already be available in most implementations of IKE by the time it is available in most implementations of IKE by the time it is made
made mandatory. To facilitate this, this document attempts to mandatory. This document attempts to identify and introduce those
identify those algorithms for future mandatory-to-implement. There algorithms for future mandatory-to-implement status. There is no
is no guarantee that the algorithms in use today may become mandatory guarantee that the algorithms in use today may become mandatory in
in the future. Published algorithms are continiously subjected to the future. Published algorithms are continuously subjected to
cryptographic attack and may become too weak or could become cryptographic attack and may become too weak or could become
completely broken before this document is updated. completely broken before this document is updated.
This document only provides recommendations for the mandatory-to- This document only provides recommendations for the mandatory-to-
implement algorithms or algorithms too weak that are recommended not implement algorithms or algorithms too weak that are recommended not
to be implemented. As a result, any algorithm not mentioned in this to be implemented. As a result, any algorithm listed at the IKEv2
document MAY be implemented. For clarification and consistency with IANA registry not mentioned in this document MAY be implemented. For
[RFC4307] an algorithm will be set to MAY only when it has been clarification and consistency with [RFC4307] an algorithm will be set
downgraded. to MAY only when it has been downgraded.
Although this document updates the algorithms in order to keep the Although this document updates the algorithms to keep the IKEv2
IKEv2 communication secure over time, it also aims at providing communication secure over time, it also aims at providing
recommendations so that IKEv2 implementations remain interoperable. recommendations so that IKEv2 implementations remain interoperable.
IKEv2 interoperability is addressed by an incremental introduction or IKEv2 interoperability is addressed by an incremental introduction or
deprecation of algorithms. In addition, this document also considers deprecation of algorithms. In addition, this document also considers
the new use cases for IKEv2 deployment, such as Internet of Things the new use cases for IKEv2 deployment, such as Internet of Things
(IoT). (IoT).
It is expected that deprecation of an algorithm is performed It is expected that deprecation of an algorithm is performed
gradually. This provides time for various implementations to update gradually. This provides time for various implementations to update
their implemented algorithms while remaining interoperable. Unless their implemented algorithms while remaining interoperable. Unless
there are strong security reasons, an algorithm is expected to be there are strong security reasons, an algorithm is expected to be
downgraded from MUST to MUST- or SHOULD, instead of MUST NOT. downgraded from MUST to MUST- or SHOULD, instead of MUST NOT.
Similarly, an algorithm that has not been mentioned as mandatory-to- Similarly, an algorithm that has not been mentioned as mandatory-to-
implement is expected to be introduced with a SHOULD instead of a implement is expected to be introduced with a SHOULD instead of a
MUST. MUST.
The current trend toward Internet of Things and its adoption of IKEv2 The current trend toward Internet of Things and its adoption of IKEv2
requires this specific use case to be taken into account as well. requires this specific use case to be taken into account as well.
IoT devices are resource constrainted devices and their choice of IoT devices are resource constrained devices and their choice of
algorithms are motivated by minimizing the fooprint of the code, the algorithms are motivated by minimizing the footprint of the code, the
computation effort and the size of the messages to send. This computation effort and the size of the messages to send. This
document indicates IoT when a specified algorithm is specifically document indicates "[IoT]" when a specified algorithm is specifically
listed for IoT devices. listed for IoT devices.
1.3. Document Audience 1.3. Document Audience
The recommendations of this document mostly target IKEv2 implementers The recommendations of this document mostly target IKEv2 implementers
as implementations needs to meet both high security expectations as as implementations need to meet both high security expectations as
well as high interoperability between various vendors and with well as high interoperability between various vendors and with
different updates. Interoperability requires a smooth move to more different versions. Interoperability requires a smooth move to more
secure cipher suites. This may differ from a user point of view that secure cipher suites. This may differ from a user point of view that
may deploy and configure IKEv2 with only the safest cipher suites. may deploy and configure IKEv2 with only the safest cipher suite. On
On the other hand, comments and recommendations are also expected to the other hand, comments and recommendations from this document are
be useful for such users. also expected to be useful for such users.
IKEv1 is out of scope of this document. IKEv1 is deprecated and the IKEv1 is out of scope of this document. IKEv1 is deprecated and the
recommendations of this document must not be considered for IKEv1. recommendations of this document must not be considered for IKEv1, as
most IKEv1 implementations have been "frozen" and will not be able to
update the list of mandatory-to-implement algorithms.
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
We define some additional terms here: We define some additional terms here:
SHOULD+ This term means the same as SHOULD. However, it is likely SHOULD+ This term means the same as SHOULD. However, it is likely
that an algorithm marked as SHOULD+ will be promoted at that an algorithm marked as SHOULD+ will be promoted at some
some future time to be a MUST. future time to be a MUST.
SHOULD- This term means the same as SHOULD. However, an algorithm SHOULD- This term means the same as SHOULD. However, an algorithm
marked as SHOULD- may be deprecated to a MAY in a future marked as SHOULD- may be deprecated to a MAY in a future
version of this document. version of this document.
MUST- This term means the same as MUST. However, we expect at MUST- This term means the same as MUST. However, we expect at some
some point that this algorithm will no longer be a MUST in point that this algorithm will no longer be a MUST in a
a future document. Although its status will be determined future document. Although its status will be determined at a
at a later time, it is reasonable to expect that if a later time, it is reasonable to expect that if a future
future revision of a document alters the status of a MUST- revision of a document alters the status of a MUST-
algorithm, it will remain at least a SHOULD or a SHOULD-. algorithm, it will remain at least a SHOULD or a SHOULD-
level.
IoT stands for Internet of Things. IoT stands for Internet of Things.
Table 1
3. Algorithm Selection 3. Algorithm Selection
3.1. Type 1 - IKEv2 Encryption Algorithm Transforms 3.1. Type 1 - IKEv2 Encryption Algorithm Transforms
The algorithms in the below table are negotiated in the SA payload The algorithms in the below table are negotiated in the SA payload
and used in the Encrypted Payload. References to the specifications and used for the Encrypted Payload. References to the specification
defining these algorithms and the ones in the following subsections defining these algorithms and the ones in the following subsections
are in the IANA registry [IKEV2-IANA]. Some of these algorithms are are in the IANA registry [IKEV2-IANA]. Some of these algorithms are
Authenticated Encryption with Associated Data (AEAD - [RFC5282]). Authenticated Encryption with Associated Data (AEAD - [RFC5282]).
Algorithms that are not AEAD MUST be used in conjunction with an Algorithms that are not AEAD MUST be used in conjunction with an
integrity algorithms in Section 3.3. integrity algorithms in Section 3.3.
+-----------------------------+----------+-------+----------+ +-----------------------------+----------+-------+----------+
| Name | Status | AEAD? | Comment | | Name | Status | AEAD? | Comment |
+-----------------------------+----------+-------+----------+ +-----------------------------+----------+-------+----------+
| ENCR_AES_CBC | MUST- | No | [1] | | ENCR_AES_CBC | MUST- | No | [1] |
skipping to change at page 5, line 46 skipping to change at page 5, line 39
| AES-GCM with a 16 octet ICV | SHOULD | Yes | [1] | | AES-GCM with a 16 octet ICV | SHOULD | Yes | [1] |
| ENCR_AES_CCM_8 | SHOULD | Yes | [1][IoT] | | ENCR_AES_CCM_8 | SHOULD | Yes | [1][IoT] |
| ENCR_3DES | MAY | No | | | ENCR_3DES | MAY | No | |
| ENCR_DES | MUST NOT | No | | | ENCR_DES | MUST NOT | No | |
+-----------------------------+----------+-------+----------+ +-----------------------------+----------+-------+----------+
[1] - This requirement level is for 128-bit keys. 256-bit keys are at [1] - This requirement level is for 128-bit keys. 256-bit keys are at
MAY. 192-bit keys can safely be ignored. [IoT] - This requirement is MAY. 192-bit keys can safely be ignored. [IoT] - This requirement is
for interoperability with IoT. for interoperability with IoT.
ENCR_AES_CBC is raised from SHOULD+ in RFC4307. It is the only Table 2
shared mandatory-to-implement algorithm with RFC4307 and as a result
is necessary for interoperability with IKEv2 implementation ENCR_AES_CBC is raised from SHOULD+ in [RFC4307] to MUST. It is the
only shared mandatory-to-implement algorithm with RFC4307 and as a
result it is necessary for interoperability with IKEv2 implementation
compatible with RFC4307. compatible with RFC4307.
ENCR_CHACHA20_POLY1305 was not ready to be considered at the time of ENCR_CHACHA20_POLY1305 was not ready to be considered at the time of
RFC4307. It has been recommended by the CRFG and others as an RFC4307. It has been recommended by the CRFG and others as an
alternative to AES and AES-GCM. It is also being standarized for alternative to AES-CBC and AES-GCM. It is also being standardized
IPsec for the same reasons. At the time of writing, there were not for IPsec for the same reasons. At the time of writing, there were
enough IKEv2 implementations of ENCR_CHACHA20_POLY1305 to be able to not enough IKEv2 implementations supporting ENCR_CHACHA20_POLY1305 to
introduce it at the SHOULD+ level. be able to introduce it at the SHOULD+ level.
AES-GCM with a 16 octet ICV was not considered as in RFC4307. At the AES-GCM with a 16 octet ICV was not considered as in RFC4307. At the
time RFC4307 was written, AES-GCM was not defined in an IETF time RFC4307 was written, AES-GCM was not defined in an IETF
document. AES-GCM was defined for ESP in [RFC4106] and later for document. AES-GCM was defined for ESP in [RFC4106] and later for
IKEv2 in [RFC5282]. The main motivation for adopting AES-GCM for ESP IKEv2 in [RFC5282]. The main motivation for adopting AES-GCM for ESP
is encryption performance as well as key longevity - compared to AES- is encryption performance and key longevity compared to AES-CBC.
CBC for example. This resulted in AES-GCM widely implemented for This resulted in AES-GCM being widely implemented for ESP. As the
ESP. As the load of IKEv2 is expected to remain relatively small, computation load of IKEv2 is relatively small compared to ESP, many
many IKEv2 implementations do not include AES-GCM. In addition to IKEv2 implementations have not implemented AES-GCM. For this reason,
its former MAY, this document does not promote AES-GCM to a greater AES-GCM is not promoted to a greater status than SHOULD. The reason
status than SHOULD so to preserve interoperability between IKEv2 for promotion from MAY to SHOULD is to promote the slightly more
implementations. [PAUL: I dont follow the reasoning, as we could secure AEAD method over the traditional encrypt+auth method. Its
have AES and AES-GCM at MUST level] This document considers AES-GCM status is expected to be raised once widely implemented. As the
as mandatory to implement to promote the slightly more secure AEAD advantage of the shorter (and weaker) ICVs is minimal, the 8 and 12
method over the traditional encrypt+auth method. Its status is octet ICV's remain at the MAY level.
expected to be raised once widely deployed.
ENCR_AES_CCM_8 was not considered in RFC4307. This document ENCR_AES_CCM_8 was not considered in RFC4307. This document
considers it SHOULD be implemented in order to be able to interact considers it as SHOULD be implemented in order to be able to interact
with Internet of Things devices. As this case is not a general use with Internet of Things devices. As this case is not a general use
case for VPNs, its status is expected to remain to SHOULD. The size case for non-IoT VPNs, its status is expected to remain as SHOULD.
of the ICV is expected to be sufficient for most use cases of IKEv2, The 8 octet size of the ICV is expected to be sufficient for most use
as far less packets are exchanged on the IKE_SA compared to the IPsec cases of IKEv2, as far less packets are exchanged on the IKE SA
SA. When implemented, ENCR_AES_CCM_8 MUST be implemented for key compared to the IPsec SA. When implemented, ENCR_AES_CCM_8 MUST be
length 128 and MAY be implemented for key length 256. implemented for key length 128 and MAY be implemented for key length
256.
ENCR_3DES has been downgraded from RFC4307 MUST-. All IKEv2 ENCR_3DES has been downgraded from RFC4307 MUST- to SHOULD NOT. All
implementation already implement ENCR_AES_CBC, so there is no need to IKEv2 implementation already implement ENCR_AES_CBC, so there is no
keep ENCR_3DES. In addition, ENCR_CHACHA20_POLY1305 provides a more need to keep support for the much slower ENCR_3DES. In addition,
modern alternative to AES. [PAUL: removed 'efficient' as we said ENCR_CHACHA20_POLY1305 provides a more modern alternative to AES.
above encryption efficiency at the IKE level hardly matters]
ENCR_DES can be brute-forced using of-the-shelves hardware. It ENCR_DES can be brute-forced using of-the-shelves hardware. It
provides no meaningful security whatsoever and therefor MUST NOT be provides no meaningful security whatsoever and therefor MUST NOT be
implemented. implemented.
3.2. Type 2 - IKEv2 Pseudo-random Function Transforms 3.2. Type 2 - IKEv2 Pseudo-random Function Transforms
Transform Type 2 Algorithms are pseudo-random functions used to Transform Type 2 Algorithms are pseudo-random functions used to
generate random values when needed. generate random values when needed.
In general, if you can trust an algorithm as INTEG algorithm, you can If an algorithm is selected as the integrity algorithm, it SHOULD
and should also use it as the PRF. When using an AEAD cipher, the also be used as the PRF. When using an AEAD cipher, a choice of PRF
choice is PRF is open, and picking one of the SHA2 variants is needs to be made. The table below lists the recommended algorithms.
recommended.
+-------------------+---------+---------+ +-------------------+----------+---------+
| Name | Status | Comment | | Name | Status | Comment |
+-------------------+---------+---------+ +-------------------+----------+---------+
| PRF_HMAC_SHA2_256 | MUST | | | PRF_HMAC_SHA2_256 | MUST | |
| PRF_HMAC_SHA2_512 | SHOULD+ | | | PRF_HMAC_SHA2_512 | SHOULD+ | |
| PRF_HMAC_SHA1 | MUST- | [1] | | PRF_HMAC_SHA1 | MUST- | |
| PRF_AES128_CBC | SHOULD | [IoT] | | PRF_AES128_CBC | SHOULD | [IoT] |
+-------------------+---------+---------+ | PRF_HMAC_MD5 | MUST NOT | |
+-------------------+----------+---------+
[IoT] - This requirement is for interoperability with IoT [IoT] - This requirement is for interoperability with IoT
Table 3
PRF_HMAC_SHA2_256 was not mentioned in RFC4307, as no SHA2 based PRF_HMAC_SHA2_256 was not mentioned in RFC4307, as no SHA2 based
authentication was mentioned. PRF_HMAC_SHA2_256 MUST be implemented authentication was mentioned. PRF_HMAC_SHA2_256 MUST be implemented
in order to replace SHA1 and PRF_HMAC_SHA1. in order to replace SHA1 and PRF_HMAC_SHA1.
PRF_HMAC_SHA2_512 SHOULD be implemented as as a future replacement of PRF_HMAC_SHA2_512 SHOULD be implemented as a future replacement for
SHA2_256 or when stronger security is required. PRF_HMAC_SHA2_512 is PRF_HMAC_SHA2_256 or for when stronger security is required.
preferred over PRF_HMAC_SHA2_384, as the overhead of PRF_HMAC_SHA2_512 is preferred over PRF_HMAC_SHA2_384, as the
PRF_HMAC_SHA2_512 is negligible. additional overhead of PRF_HMAC_SHA2_512 is negligible.
PRF_HMAC_SHA1_96 has been downgraded from MUST in RFC4307. There is PRF_HMAC_SHA1 has been downgraded from MUST in RFC4307 to MUST- as
an industry-wide trend to deprecate its usage. their is an industry-wide trend to deprecate its usage.
PRF_AES128_CBC is only recommended in the scope of IoT, as Internet PRF_AES128_CBC is only recommended in the scope of IoT, as Internet
of Things deployments tend to prefer AES based pseudo-random of Things deployments tend to prefer AES based pseudo-random
functions in order to avoid implementing SHA2. For the wide VPN functions in order to avoid implementing SHA2. For the non-IoT VPN
deployment, as it has not been widely adopted, it has been downgraded deployment it has been downgraded from SHOULD in RFC4307 to MAY as it
from SHOULD in RFC4307 to MAY. has not seen wide adoption.
PRF_HMAC_MD5 has been downgraded from MAY in RFC4307 to MUST NOT.
There is an industry-wide trend to deprecate its usage as MD5 support
is being removed from cryptographic libraries in general because its
non-HMAC use is known to be subject to collision attacks, for example
as mentioned in [TRANSCRIPTION].
3.3. Type 3 - IKEv2 Integrity Algorithm Transforms 3.3. Type 3 - IKEv2 Integrity Algorithm Transforms
The algorithms in the below table are negotiated in the SA payload The algorithms in the below table are negotiated in the SA payload
and used in the ENCR payload. References to the specifications and used for the Encrypted Payload. References to the specification
defining these algorithms are in the IANA registry. When an AEAD defining these algorithms are in the IANA registry. When an AEAD
algorithm (see Section 3.1) is proposed, this algorithm transform algorithm (see Section 3.1) is proposed, this algorithm transform
type is not in use. type is not in use.
+------------------------+--------+---------+ +------------------------+----------+---------+
| Name | Status | Comment | | Name | Status | Comment |
+------------------------+--------+---------+ +------------------------+----------+---------+
| AUTH_HMAC_SHA2_256_128 | MUST | | | AUTH_HMAC_SHA2_256_128 | MUST | |
| AUTH_HMAC_SHA2_512_256 | SHOULD | | | AUTH_HMAC_SHA2_512_256 | SHOULD | |
| AUTH_HMAC_SHA1_96 | SHOULD | | | AUTH_HMAC_SHA1_96 | MUST- | |
| AUTH_AES_XCBC_96 | SHOULD | [IoT] | | AUTH_AES_XCBC_96 | SHOULD | [IoT] |
+------------------------+--------+---------+ | AUTH_HMAC_MD5_96 | MUST NOT | |
| AUTH_DES_MAC | MUST NOT | |
| AUTH_KPDK_MD5 | MUST NOT | |
+------------------------+----------+---------+
[IoT] - This requirement is for interoperability with IoT [IoT] - This requirement is for interoperability with IoT
Table 4
AUTH_HMAC_SHA2_256_128 was not mentioned in RFC4307, as no SHA2 based AUTH_HMAC_SHA2_256_128 was not mentioned in RFC4307, as no SHA2 based
authentication was mentioned. AUTH_HMAC_SHA2_256_128 MUST be authentication was mentioned. AUTH_HMAC_SHA2_256_128 MUST be
implemented in order to replace AUTH_HMAC_SHA1_96. implemented in order to replace AUTH_HMAC_SHA1_96.
AUTH_HMAC_SHA2_512_256 SHOULD be implemented as as a future AUTH_HMAC_SHA2_512_256 SHOULD be implemented as a future replacement
replacement of AUTH_HMAC_SHA2_256_128 or when stronger security is of AUTH_HMAC_SHA2_256_128 or for when stronger security is required.
required. This value has been preferred to AUTH_HMAC_SHA2_384, as This value has been preferred over AUTH_HMAC_SHA2_384, as the
the overhead of AUTH_HMAC_SHA2_512 is negligible. additional overhead of AUTH_HMAC_SHA2_512 is negligible.
AUTH_HMAC_SHA1_96 has been downgraded from MUST in RFC4307. There is AUTH_HMAC_SHA1_96 has been downgraded from MUST in RFC4307 to MUST-
an industry-wide trend to deprecate its usage. as there is an industry-wide trend to deprecate its usage.
AUTH_AES-XCBC is only recommended in the scope of IoT, as Internet of AUTH_AES-XCBC is only recommended in the scope of IoT, as Internet of
Things deployments tend to prefer AES based pseudo-random functions Things deployments tend to prefer AES based pseudo-random functions
in order to avoid implementing SHA2. For the wide VPN deployment, as in order to avoid implementing SHA2. For the non-IoT VPN deployment,
it has not been widely adopted, it has been downgraded from SHOULD in it has been downgraded from SHOULD in RFC4307 to MAY as it has not
RFC4307 to MAY. been widely adopted.
3.4. Type 4 - IKEv2 Diffie-Hellman Group Transforms AUTH_HMAC_MD5_96, AUTH_DES_MAC and AUTH_KPDK_MD5 were not mentioned
in RFC4307 so its default status was MAY. It has been downgraded to
MUST NOT. There is an industry-wide trend to deprecate its usage.
MD5 support is being removed from cryptographic libraries in general
because its non-HMAC use is known to be subject to collision attacks,
for example as mentioned in [TRANSCRIPTION].
3.4. Type 4 - IKEv2 Diffie-Hellman Group Transforms
There are several Modular Exponential (MODP) groups and several There are several Modular Exponential (MODP) groups and several
Elliptic Curve groups (ECC) that are defined for use in IKEv2. They Elliptic Curve groups (ECC) that are defined for use in IKEv2. These
are defined in both the [IKEv2] base document and in extensions groups are defined in both the [IKEv2] base document and in
documents. They are identified by group number. extensions documents and are identified by group number. Note that
it is critical to enforce a secure Diffie Hellman exchange as this
exchange provides encryption for the session. If an attacker can
retrieve the private numbers (for example a, b) (and? or?) the public
values (for example g**a, g**b), then the attacker can compute the
secret and the keys used and decrypt the exchange. Such an attack
can be performed off-line on a previously recorded communication,
years after the communication happened. This differs from attacks
that need to be executed during the authentication which must be
performed online and in near real-time.
+--------+----------------------------------------------+-----------+ +------------+----------------------------------------+-------------+
| Number | Description | Status | | Number | Description | Status |
+--------+----------------------------------------------+-----------+ +------------+----------------------------------------+-------------+
| 14 | 2048-bit MODP Group | MUST | | 14 | 2048-bit MODP Group | MUST |
| 19 | 256-bit random ECP group | SHOULD | | 19 | 256-bit random ECP group | SHOULD |
| 5 | 1536-bit MODP Group | SHOULD | | 5 | 1536-bit MODP Group | SHOULD NOT |
| | | NOT | | 2 | 1024-bit MODP Group | SHOULD NOT |
| 2 | 1024-bit MODP Group | SHOULD | | 1 | 768-bit MODP Group | MUST NOT |
| | | NOT | | 22 | 1024-bit MODP Group with 160-bit Prime | SHOULD NOT |
| 1 | 768-bit MODP Group | MUST NOT | | | Order Subgroup | |
| 22 | 1024-bit MODP Group with 160-bit Prime Order | MUST NOT | | 23 | 2048-bit MODP Group with 224-bit Prime | SHOULD NOT |
| | Subgroup | | | | Order Subgroup | |
| 23 | 1024-bit MODP Group with 224-bit Prime Order | MUST NOT | | 24 | 2048-bit MODP Group with 256-bit Prime | SHOULD NOT |
| | Subgroup | | | | Order Subgroup | |
| 24 | 1024-bit MODP Group with 256-bit Prime Order | MUST NOT | +------------+----------------------------------------+-------------+
| | Subgroup | |
+--------+----------------------------------------------+-----------+ Table 5
Group 14 or 2048-bit MODP Group is raised from SHOULD+ in RFC4307 as Group 14 or 2048-bit MODP Group is raised from SHOULD+ in RFC4307 as
a replacement for 1024-bit MODP Group. Group 14 is widely a replacement for 1024-bit MODP Group. Group 14 is widely
implemented and considered secure implemented and considered secure.
Group 19 or 256-bit random ECP group was not specified in RFC4307.
Group 19 is widely implemented and considered secure
Group 5 or 1536-bit MODP Group is downgrade from MUST- to SHOULD NOT. Group 19 or 256-bit random ECP group was not specified in RFC4307, as
It was specified earlier, but now considered to be vulnerable to be this group were not specified at that time. Group 19 is widely
broken within the next few years by a nation state level attack, so implemented and considered secure.
its security margin is considered too narrow.
Group 2 or 1024-bit MODP Group is downgrade from MUST- to SHOULD NOT. Group 5 or 1536-bit MODP Group has been downgraded from MAY in
It was specified earlier, but now it is known to be weak against RFC4307 to SHOULD NOT. It was specified earlier, but is now
sufficiently funded attackers using commercially available mass- considered to be vulnerable to be broken within the next few years by
computing resources, so its security margin is considered too narrow. a nation state level attack, so its security margin is considered too
It is expected in the near future to be downgraded to MUST NOT. narrow.
Group 1 or 768-bit MODP Group can be broken within hours using cheap Group 2 or 1024-bit MODP Group has been downgraded from MUST- in
of-the-shelves hardware. It provides no security whatsoever. RFC4307 to SHOULD NOT. It is known to be weak against sufficiently
funded attackers using commercially available mass-computing
resources, so its security margin is considered too narrow. It is
expected in the near future to be downgraded to MUST NOT.
Curve25519 has been designed with performance and security in mind Group 1 or 768-bit MODP Group was not mentioned in RFC4307 and so its
and have been recommended by CFRG. At the time of writing, the IKEv2 status was MAY. It can be broken within hours using cheap of-the-
specification is still at the draft status. This document specifies shelves hardware. It provides no security whatsoever.
it as to encourage its implementation and deployment. If it gets
widely implemented then it most likely will be upgraded to SHOULD or
even MUST in the future.
Group 22-24 or 1024-bit MODP Group with 160-bit and 2048-bit MODP Group 22, 23 and 24 or 1024-bit MODP Group with 160-bit, and 2048-bit
Group with 224-256-bit Prime Order Subgroup are exposed to MODP Group with 224-bit and 256-bit Prime Order Subgroup have small
synchronization or transcription attacks. subgroups, which means that checks specified in the "Additional
Diffie-Hellman Test for the IKEv2" [RFC6989] section 2.2 first bullet
point MUST be done when these groups are used. These groups are also
not safe-primes. The seeds for these groups have not been publicly
released, resulting in reduced trust in these groups. These groups
were proposed as alternatives for group 2 and 14 but never saw wide
deployment. It is expected in the near future to be further
downgraded to MUST NOT.
4. IKEv2 Authentication 4. IKEv2 Authentication
IKEv2 authentication may involve a signatures verification. IKEv2 authentication may involve a signatures verification.
Signatures may be used to validate a certificate or to check the Signatures may be used to validate a certificate or to check the
signature of the AUTH value. Cryptographic recommendations regarding signature of the AUTH value. Cryptographic recommendations regarding
certificate validation are out of scope of this document as what certificate validation are out of scope of this document. What is
mandatory implementations are provided by the PKIX WG. This document mandatory to implement is provided by the PKIX Community. This
is mostly concerned on signature verification and generation for the document is mostly concerned on signature verification and generation
authentication. for the authentication.
4.1. IKEv2 Authentication Method 4.1. IKEv2 Authentication Method
+--------+-------------------------+--------+-----------------------+ +--------+---------------------------------------+------------+
| Number | Description | Status | Comment | | Number | Description | Status |
+--------+-------------------------+--------+-----------------------+ +--------+---------------------------------------+------------+
| 1 | RSA Digital Signature | MUST | With keys length 2048 | | 1 | RSA Digital Signature | MUST |
| 1 | RSA Digital Signature | SHOULD | With keys length | | 3 | DSS Digital Signature | SHOULD NOT |
| | | | 3072/4096 | | 9 | ECDSA with SHA-256 on the P-256 curve | SHOULD |
| 1 | RSA Digital Signature | MUST | With keys length | | 10 | ECDSA with SHA-384 on the P-384 curve | SHOULD |
| | | NOT | lower than 2048 | | 11 | ECDSA with SHA-512 on the P-521 curve | SHOULD |
| 3 | DSS Digital Signature | MAY | | | 14 | Digital Signature | SHOULD |
| 9 | ECDSA with SHA-256 on | SHOULD | | +--------+---------------------------------------+------------+
| | the P-256 curve | | |
| 10 | ECDSA with SHA-384 on | SHOULD | |
| | the P-384 curve | | |
| 11 | ECDSA with SHA-512 on | SHOULD | |
| | the P-521 curve | | |
| 14 | Digital Signature | SHOULD | |
+--------+-------------------------+--------+-----------------------+
RSA Digital Signature is mostly kept for interoperability. It is Table 6
expected to be downgraded in the future as signatures are based on
RSASSA-PKCS1-v1.5, not any more recommemded. Instead, more robust RSA Digital Signature is widely deployed and therefor kept for
use of RSA is expected to be performed via the Digital Signature interoperability. It is expected to be downgraded in the future as
its signatures are based on the older RSASSA-PKCS1-v1.5 which is no
longer recommended. RSA authentication, as well as other specific
Authentication Methods, are expected to be replaced with the generic
Digital Signature method of [RFC7427]. RSA Digital Signature is not
recommended for keys smaller then 2048, but since these signatures
only have value in real-time, and need no future protection, smaller
keys was kept at SHOULD NOT instead of MUST NOT.
ECDSA based Authentication Methods are also expected to be downgraded
as it does not provide hash function agility. Instead, ECDSA (like
RSA) is expected to be performed using the generic Digital Signature
method. method.
ECDSA family are also expected to be downgraded as it does not DSS Digital Signature is bound to SHA-1 and has the same level of
provide hash function agility. Instead ECDSA is expected to be security as 1024-bit RSA. It is expected to be downgraded to MUST
performed using the generic Digital Signature method. NOT in the future.
DSS Digital Signature is bound to SHA-1 and thus is expected to be Digital Signature [RFC7427] is expected to be promoted as it provides
downgraded to MUST NOT in the future. hash function, signature format and algorithm agility.
Digital Signature is expected to be promoted as it provides hash 4.1.1. Recommendations for RSA key length
function, signature format and algorithm agility.
[MGLT: Do we have any recommendation for the authentication based on +-------------------------------------------+------------+
PSK?] | Description | Status |
+-------------------------------------------+------------+
| RSA with key length 2048 | MUST |
| RSA with key length 3072 and 4096 | SHOULD |
| RSA with key length between 2049 and 4095 | MAY |
| RSA with key length smaler than 2048 | SHOULD NOT |
+-------------------------------------------+------------+
4.2. Digital Signature Recommendation Table 7
Here are the recommendations for the authentication methods. 4.2. Digital Signature Recommendations
+--------+-------------+----------+---------------------------------+ Recommendations for when a hash function is involved in a signature:
| Number | Description | Status | Comment |
+--------+-------------+----------+---------------------------------+
| OID | RSA | MUST | With keys length 2048 |
| OID | RSA | SHOULD | With keys length 3072/4096 |
| OID | RSA | MUST NOT | With keys length lower than |
| | | | 2048 |
| OID | ECDSA | SHOULD | |
+--------+-------------+----------+---------------------------------+
Here are the recommendations when a hash function is involved in a +--------+-------------+------------+---------+
signature. | Number | Description | Status | Comment |
+--------+-------------+------------+---------+
| 1 | SHA1 | SHOULD NOT | |
| 2 | SHA2-256 | MUST | |
| 3 | SHA2-384 | MAY | |
| 4 | SHA2-512 | SHOULD | |
+--------+-------------+------------+---------+
+--------+-------------+--------+---------+ Table 8
| Number | Description | Status | Comment |
+--------+-------------+--------+---------+
| 1 | SHA1 | MUST | |
| 2 | SHA2-256 | MUST | |
| 3 | SHA2-384 | MAY | |
| 4 | SHA2-512 | SHOULD | |
+--------+-------------+--------+---------+
With the use of Digital Signature, RSASSA-PKCS1-v1.5 MAY be With the use of Digital Signature, RSASSA-PKCS1-v1.5 MAY be
implemented, and RSASSA-PSS MUST be implemented. implemented. RSASSA-PSS MUST be implemented.
Recommendation of Authentication Method described in [RFC7427]
notation:
+------------------------------------+------------+---------+
| Description | Status | Comment |
+------------------------------------+------------+---------+
| RSASSA-PSS with SHA-256 | SHOULD | |
| ecdsa-with-sha256 | SHOULD | |
| sha1WithRSAEncryption | SHOULD NOT | |
| dsa-with-sha1 | SHOULD NOT | |
| ecdsa-with-sha1 | SHOULD NOT | |
| RSASSA-PSS with Empty Parameters | SHOULD NOT | |
| RSASSA-PSS with Default Parameters | SHOULD NOT | |
| sha256WithRSAEncryption | MAY | |
| sha384WithRSAEncryption | MAY | |
| sha512WithRSAEncryption | MAY | |
| sha512WithRSAEncryption | MAY | |
| dsa-with-sha256 | MAY | |
| ecdsa-with-sha384 | MAY | |
| ecdsa-with-sha512 | MAY | ?SHOULD |
+------------------------------------+------------+---------+
Table 9
5. Security Considerations 5. Security Considerations
The security of cryptographic-based systems depends on both the The security of cryptographic-based systems depends on both the
strength of the cryptographic algorithms chosen and the strength of strength of the cryptographic algorithms chosen and the strength of
the keys used with those algorithms. The security also depends on the keys used with those algorithms. The security also depends on
the engineering of the protocol used by the system to ensure that the engineering of the protocol used by the system to ensure that
there are no non-cryptographic ways to bypass the security of the there are no non-cryptographic ways to bypass the security of the
overall system. overall system.
The Diffie-Hellman Groups parameter is the most important one to The Diffie-Hellman Group parameter is the most important one to
choose conservatively. Any party capturing all traffic that can choose conservatively. Any party capturing all IKE and ESP traffic
break the selected DH group can retroactively gain access to the that (even years later) can break the selected DH group in IKE, can
symmetric keys used to encrypt all the IPsec data. However, gain access to the symmetric keys used to encrypt all the ESP
specifying extremely large DH group also puts a considerable load on traffic. Therefore, these groups must be chosen very conservatively.
the device, especially when this is a large VPN gateway or an IoT However, specifying an extremely large DH group also puts a
constrained device. considerable load on the device, especially when this is a large VPN
gateway or an IoT constrained device.
This document concerns itself with the selection of cryptographic This document concerns itself with the selection of cryptographic
algorithms for the use of IKEv2, specifically with the selection of algorithms for the use of IKEv2, specifically with the selection of
"mandatory-to-implement" algorithms. The algorithms identified in "mandatory-to-implement" algorithms. The algorithms identified in
this document as "MUST implement" or "SHOULD implement" are not known this document as "MUST implement" or "SHOULD implement" are not known
to be broken at the current time, and cryptographic research so far to be broken at the current time, and cryptographic research so far
leads us to believe that they will likely remain secure into the leads us to believe that they will likely remain secure into the
foreseeable future. However, this isn't necessarily forever and it foreseeable future. However, this isn't necessarily forever and it
is expected that new revisions of this document will be issued from is expected that new revisions of this document will be issued from
time to time to reflect the current best practice in this area. time to time to reflect the current best practice in this area.
skipping to change at page 12, line 28 skipping to change at page 13, line 18
6. IANA Considerations 6. IANA Considerations
This document makes no requests of IANA. This document makes no requests of IANA.
7. Acknowledgements 7. Acknowledgements
The first version of this document was RFC 4307 by Jeffrey I. The first version of this document was RFC 4307 by Jeffrey I.
Schiller of the Massachusetts Institute of Technology (MIT). Much of Schiller of the Massachusetts Institute of Technology (MIT). Much of
the original text has been copied verbatim. the original text has been copied verbatim.
We would like to thanks Paul Hoffman, Yaron Sheffer John Mattsson and We would like to thank Paul Hoffman, Yaron Sheffer, John Mattsson and
Tommy Pauly for their valuable feed backs. Tommy Pauly for their valuable feedback.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
DOI 10.17487/RFC2119, March 1997, RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC4106] Viega, J. and D. McGrew, "The Use of Galois/Counter Mode [RFC4106] Viega, J. and D. McGrew, "The Use of Galois/Counter Mode
(GCM) in IPsec Encapsulating Security Payload (ESP)", (GCM) in IPsec Encapsulating Security Payload (ESP)", RFC
RFC 4106, DOI 10.17487/RFC4106, June 2005, 4106, DOI 10.17487/RFC4106, June 2005,
<http://www.rfc-editor.org/info/rfc4106>. <http://www.rfc-editor.org/info/rfc4106>.
[RFC4307] Schiller, J., "Cryptographic Algorithms for Use in the [RFC4307] Schiller, J., "Cryptographic Algorithms for Use in the
Internet Key Exchange Version 2 (IKEv2)", RFC 4307, Internet Key Exchange Version 2 (IKEv2)", RFC 4307, DOI
DOI 10.17487/RFC4307, December 2005, 10.17487/RFC4307, December 2005,
<http://www.rfc-editor.org/info/rfc4307>. <http://www.rfc-editor.org/info/rfc4307>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2 Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <http://www.rfc-editor.org/info/rfc7296>. 2014, <http://www.rfc-editor.org/info/rfc7296>.
[RFC5282] Black, D. and D. McGrew, "Using Authenticated Encryption [RFC5282] Black, D. and D. McGrew, "Using Authenticated Encryption
Algorithms with the Encrypted Payload of the Internet Key Algorithms with the Encrypted Payload of the Internet Key
Exchange version 2 (IKEv2) Protocol", RFC 5282, Exchange version 2 (IKEv2) Protocol", RFC 5282, DOI
DOI 10.17487/RFC5282, August 2008, 10.17487/RFC5282, August 2008,
<http://www.rfc-editor.org/info/rfc5282>. <http://www.rfc-editor.org/info/rfc5282>.
8.2. Informative References 8.2. Informative References
[RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in
the Internet Key Exchange Version 2 (IKEv2)", RFC 7427,
DOI 10.17487/RFC7427, January 2015,
<http://www.rfc-editor.org/info/rfc7427>.
[RFC6989] Sheffer, Y. and S. Fluhrer, "Additional Diffie-Hellman
Tests for the Internet Key Exchange Protocol Version 2
(IKEv2)", RFC 6989, DOI 10.17487/RFC6989, July 2013,
<http://www.rfc-editor.org/info/rfc6989>.
[IKEV2-IANA] [IKEV2-IANA]
"Internet Key Exchange Version 2 (IKEv2) Parameters", , "Internet Key Exchange Version 2 (IKEv2) Parameters", ,
<http://www.iana.org/assignments/ikev2-parameters>. <http://www.iana.org/assignments/ikev2-parameters>.
[TRANSCRIPTION]
Bhargavan, K. and G. Leurent, "Transcript Collision
Attacks: Breaking Authentication in TLS, IKE, and SSH",
NDSS , feb 2016.
Authors' Addresses Authors' Addresses
Yoav Nir Yoav Nir
Check Point Software Technologies Ltd. Check Point Software Technologies Ltd.
5 Hasolelim st. 5 Hasolelim st.
Tel Aviv 6789735 Tel Aviv 6789735
Israel Israel
EMail: ynir.ietf@gmail.com EMail: ynir.ietf@gmail.com
 End of changes. 74 change blocks. 
254 lines changed or deleted 330 lines changed or added

This html diff was produced by rfcdiff 1.44. The latest version is available from http://tools.ietf.org/tools/rfcdiff/