Internet DRAFT - draft-ietf-lwig-minimal-esp
draft-ietf-lwig-minimal-esp
Light-Weight Implementation Guidance (lwig) D. Migault
Internet-Draft Ericsson
Intended status: Informational T. Guggemos
Expires: 27 March 2023 LMU Munich
23 September 2022
Minimal IP Encapsulating Security Payload (ESP)
draft-ietf-lwig-minimal-esp-12
Abstract
This document describes the minimal properties that an IP
Encapsulating Security Payload (ESP) implementation needs to meet to
remain interoperable with the standard RFC4303 ESP. Such a minimal
version of ESP is not intended to become a replacement of the RFC
4303 ESP. Instead, a minimal implementation is expected to be
optimized for constrained environments while remaining interoperable
with implementations of RFC 4303 ESP. In addition, this document
also provides some considerations for implementing minimal ESP in a
constrained environment which includes limiting the number of flash
writes, handling frequent wakeup / sleep states, limiting wakeup
time, and reducing the use of random generation.
This document does not update or modify RFC 4303. It provides a
compact description of how to implement the minimal version of that
protocol. RFC 4303 remains the authoritative description.
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 of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents 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 27 March 2023.
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Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Security Parameter Index (SPI) (32 bit) . . . . . . . . . . . 4
3.1. Considerations over SPI generation . . . . . . . . . . . 4
4. Sequence Number(SN) (32 bit) . . . . . . . . . . . . . . . . 6
5. Padding . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Next Header (8 bit) and Dummy Packets . . . . . . . . . . . . 9
7. ICV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8. Cryptographic Suites . . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
10. Security Considerations . . . . . . . . . . . . . . . . . . . 11
11. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12
12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 12
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
13.1. Normative References . . . . . . . . . . . . . . . . . . 13
13.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Requirements notation
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.
2. Introduction
ESP [RFC4303] is part of the IPsec protocol suite [RFC4301]. IPsec
is used to provide confidentiality, data origin authentication,
connectionless integrity, an anti-replay service and limited traffic
flow confidentiality (TFC) padding.
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Figure 1 describes an ESP Packet. Currently, ESP is implemented in
the kernel of most major multipurpose Operating Systems (OS). ESP is
usually implemented with all of its features to fit the multiple
purpose usage of these OSes, at the expense of resources and with no
considerations for code size. Constrained devices are likely to have
their own implementation of ESP optimized and adapted to their
specific use, such as limiting the number of flash writes (for each
packet or across wake time), handling frequent wakeup and sleep
state, limiting wakeup time, and reducing the use of random
generation. With the adoption of IPsec by IoT devices with minimal
IKEv2 [RFC7815] and ESP Header Compression (EHC) with
[I-D.mglt-ipsecme-diet-esp] or
[I-D.mglt-ipsecme-ikev2-diet-esp-extension], these ESP
implementations MUST remain interoperable with standard ESP
implementations. This document describes the minimal properties an
ESP implementation needs to meet to remain interoperable with
[RFC4303] ESP. In addition, this document also provides advise to
implementers for implementing ESP within constrained environments.
This document does not update or modify RFC 4303.
For each field of the ESP packet represented in Figure 1 this
document provides recommendations and guidance for minimal
implementations. The primary purpose of Minimal ESP is to remain
interoperable with other nodes implementing RFC 4303 ESP, while
limiting the standard complexity of the implementation.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----
| Security Parameters Index (SPI) | ^Int.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Cov-
| Sequence Number | |ered
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ----
| Payload Data* (variable) | | ^
~ ~ | |
| | |Conf.
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Cov-
| | Padding (0-255 bytes) | |ered*
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| | Pad Length | Next Header | v v
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ------
| Integrity Check Value-ICV (variable) |
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: ESP Packet Description
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3. Security Parameter Index (SPI) (32 bit)
[RFC4303] defines the SPI as a mandatory 32 bits field.
The SPI has a local significance to index the Security Association
(SA). From [RFC4301] section 4.1, nodes supporting only unicast
communications can index their SA using only the SPI. Nodes
supporting multicast communications also require to use the IP
addresses and thus SA lookup need to be performed using the longest
match.
For nodes supporting only unicast communications, it is RECOMMENDED
indexing the SA using only the SPI. The index may be based on the
full 32 bits of SPI or a subset of these bits. The node may require
a combination of the SPI as well as other parameters (like the IP
address) to index the SA.
Values 0-255 MUST NOT be used. As per section 2.1 of [RFC4303],
values 1-255 are reserved and 0 is only allowed to be used internally
and it MUST NOT be sent over the wire.
[RFC4303] does not require the 32 bit SPI to be randomly generated,
although that is the RECOMMENDED way to generate SPIs as it provides
some privacy and security benefits and avoids correlation between ESP
communications. To obtain a usable random 32 bit SPI, the node
generates a random 32 bit value and checks it does not fall within
the 0-255 range. If the SPI has an acceptable value, it is used to
index the inbound session. Otherwise the generated value is
discarded and the process repeats until a valid value is found.
Some constrained devices are less concerned with the privacy
properties associated to randomly generated SPIs. Examples of such
devices might include sensors looking to reduce their code
complexity. The use of a predictive function to generate the SPI
might be preferred over the generation and handling of random values.
An implementation of such predictable function could use the
combination of a fixed value and the memory address of the SAD
structure. For every incoming packet, the node will be able to point
to the SAD structure directly from the SPI value. This avoids having
a separate and additional binding and lookup function for the SPI to
its SAD entry for every incoming packet.
3.1. Considerations over SPI generation
SPIs that are not randomly generated over 32 bits may have privacy
and security concerns. As a result, the use of alternative designs
requires careful security and privacy reviews. This section provides
some considerations upon the adoption of alternative designs.
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The SPI value is only looked up for inbound traffic. The SPI
negotiated with IKEv2 [RFC7296] or Minimal IKEv2 [RFC7815] by a peer
is the value used by the remote peer when it sends traffic. The main
advantage of using a rekeying mechanism is to enable a rekey, that is
performed by replacing an old SA by a new SA, both indexed with
distinct SPIs. As the SPI is only used for inbound traffic by the
peer, this allows each peer to manage the set of SPIs used for its
inbound traffic. The necessary number of SPI reflects the number of
inbound SAs as well as the ability to rekey these SAs. Typically,
rekeying a SA is performed by creating a new SA (with a dedicated
SPI) before the old SA is deleted. This results in an additional SA
and the need to support an additional SPI. Similarly, the privacy
concerns associated with the generation of non-random SPIs is also
limited to the incoming traffic.
Alternatively, some constrained devices will not implement IKEv2 or
Minimal IKEv2 and as such will not be able to manage a roll-over
between two distinct SAs. In addition, some of these constrained
devices are also likely to have a limited number of SAs - likely to
be indexed over 3 bytes only for example. One possible way to enable
a rekey mechanism with these devices is to use the SPI where for
example the first 3 bytes designates the SA while the remaining byte
indicates a rekey index. SPI numbers can be used to implement
tracking the inbound SAs when rekeying is taking place. When
rekeying a SPI, the new SPI could use the SPI bytes to indicate the
rekeying index.
The use of a small limited set of SPI numbers across communications
comes with privacy and security concerns. Some specific values or
subset of SPI values could reveal the models or manufacturer of the
node implementing ESP. It could also reveal some state such as "not
yet rekeyed" or "rekeyed 10 times". If a constrained host uses a
very limited or even just one application, the SPI itself could
indicate what kind of traffic (eg the kind of application typically
running) is transmitted. This could be further correlated by
encrypted data size to further leak information to an observer on the
network. In addition, use of specific hardcoded SPI numbers could
reveal a manufacturer or device version. If updated devices use
different SPI numbers, an attacker could locate vulnerable devices by
their use of specific SPI numbers.
A privacy analysis should consider at least the type of information
as well the traffic pattern before deciding whether non-random SPIs
are safe to use. Typically temperature sensors, wind sensors, used
outdoors may not leak privacy sensitive information and most of its
traffic is expected to be outbound traffic. When used indoors, a
sensor that reports an encrypted status of a door (closed or opened)
every minute, might not leak sensitive information outside the local
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network. In these examples, the privacy aspect of the information
itself might be limited. Being able to determine the version of the
sensor to potentially take control of it may also have some limited
security consequences. Of course this depends on the context these
sensors are being used. If the risks associated to privacy and
security are acceptable, a non-randomized SPI can be used.
4. Sequence Number(SN) (32 bit)
The Sequence Number (SN) in [RFC4303] is a mandatory 32 bits field in
the packet.
The SN is set by the sender so the receiver can implement anti-replay
protection. The SN is derived from any strictly increasing function
that guarantees: if packet B is sent after packet A, then SN of
packet B is higher than the SN of packet A.
Some constrained devices may establish communication with specific
devices where it is known whether or not the peer implements anti-
replay protection. As per [RFC4303], the sender MUST still implement
a strictly increasing function to generate the SN.
The RECOMMENDED way for multipurpose ESP implementation is to
increment a counter for each packet sent. However, a constrained
device may avoid maintaining this context and use another source that
is known to always increase. Typically, constrained devices use
802.15.4 Time Slotted Channel Hopping (TSCH). This communication is
heavily dependent on time. A contrained device can take advantage of
this clock mechanism to generate the SN. A lot of IoT devices are in
a sleep state most of the time and wake up only to perform a specific
operation before going back to sleep. These devices do have separate
hardware that allows them to wake up after a certain timeout and
typically also timers that start running when the device was booted
up, so they might have a concept of time with certain granularity.
This requires to store any information in a stable storage - such as
flash memory - that can be restored across sleeps. Storing
information associated with the SA such as SN requires some read and
write operation on a stable storage after each packet is sent as
opposed to a SPI number or cryptographic keys that are only written
to stable storage at the creation of the SA. Write operations wear
out the flash storage. Write operations also slow down the system
significantly, as writing to flash is much slower than reading from
flash. While these devices have internal clocks or timers that might
not be very accurate, these are good enough to guarantee that each
time the device wakes up from sleep that their time is greater than
what it was before the device went to sleep. Using time for the SN
would guarantee a strictly increasing function and avoid storing any
additional values or context related to the SN on flash. In addition
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to the time value, a RAM based counter can be used to ensure that if
the device sends multiple packets over an SA within one wake up
period, that the serial numbers are still increasing and unique.
For inbound traffic, it is RECOMMENDED that receivers implement anti-
replay protection. The size of the window should depend on the
property of the network to deliver packets out of order. In an
environment where out of order packets are not possible, the window
size can be set to one. An ESP implementation may choose to not
implement an anti-replay protection. An implementation of anti-
replay protection may require the device to write the received SN for
every packet to stable storage. This will have the same issues as
discussed earlier with the SN. Some constrained device
implementations may choose to not implement the optional anti-replay
protection. A typical example might consider an IoT device such as a
temperature sensor that is sending a temperature measurement every 60
seconds, and that receives an acknowledgment from the receiver. In
such cases, the ability to spoof and replay an acknowledgement is of
limited interest and might not justify the implementation of an anti-
replay mechanism. Receiving peers may also use ESP anti-replay
mechanism adapted to a specific application. Typically, when the
sending peer is using SN based on time, anti-replay may be
implemented by discarding any packets that present a SN whose value
is too much in the past. Such mechanisms may consider clock drifting
in various ways in addition to acceptable delay induced by the
network to avoid the anti replay windows rejecting legitimate
packets. It could accept any SN as long as it is higher than the
previously received SN. Another mechanism could be used where only
the received time on the device is used to consider a packet as
valid, without looking at the SN at all.
The SN can be represented as a 32 bit number, or as a 64 bit number,
known as Extended Sequence Number (ESN). As per [RFC4303], support
of ESN is not mandatory and its use is negotiated via IKEv2
[RFC7296]. A ESN is used for high speed links to ensure there can be
more than 2^32 packets before the SA needs to be rekeyed to prevent
the SN from rolling over. This assumes the SN is incremented by 1
for each packet. When the SN is incremented differently - such as
when time is used - rekeying needs to happen based on how the SN is
incremented to prevent the SN from rolling over. The security of all
data protected under a given key decreases slightly with each message
and a node must ensure the limit is not reached - even though the SN
would permit it. Estimation of the maximum number of packets to be
sent by a node is not always predicatable and large margins should be
used espcially as nodes could be online for much more time than
expected. Even for constrained devices, it is RECOMMENDED to
implement some rekey mechanisms (see Section 10).
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5. Padding
Padding is required to keep the 32 bit alignment of ESP. It is also
required for some encryption transforms that need a specific block
size of input, such as ENCR_AES_CBC. ESP specifies padding in the
Pad Length byte, followed by up to 255 bytes of padding.
Checking the padding structure is not mandatory, so constrained
devices may omit these checks on received ESP packets. For outgoing
ESP packets, padding must be applied as required by ESP.
In some situation the padding bytes may take a fixed value. This
would typically be the case when the Data Payload is of fixed size.
ESP [RFC4303] additionally provides Traffic Flow Confidentiality
(TFC) as a way to perform padding to hide traffic characteristics.
TFC is not mandatory and is negotiated with the SA management
protocol, such as IKEv2. TFC has been widely implemented but it is
not widely deployed for ESP traffic. It is NOT RECOMMENDED to
implement TFC for a minimal ESP.
As a consequence, communication protection that relies on TFC would
be more sensitive to traffic patterns without TFC. This can leak
application information as well as the manifacturor or model of the
device used to a passive monitoring attacker. Such information can
be used, for example, by an attacker in case a vulnerability is known
for the specific device or application. In addition, some
application use - such as health applications - could leak important
privacy oriented information.
Constrained devices that have limited battery lifetime may prefer to
avoid sending extra padding bytes. In most cases, the payload
carried by these devices is quite small, and the standard padding
mechanism can be used as an alternative to TFC. Alternatively, any
information leak based on the size - or presence - of the packet can
also be addressed at the application level, before the packet is
encrypted with ESP. If application packets vary between 1 to 30
bytes, the application could always send 32 byte responses to ensure
all traffic sent is of identical length. To prevent leaking
information that a sensor changed state, such as "temperature
changed" or "door opened", an application could send this information
at regular time interval, rather than when a specific event is
happening, even if the sensor state did not change.
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6. Next Header (8 bit) and Dummy Packets
ESP [RFC4303] defines the Next Header as a mandatory 8 bits field in
the packet. The Next header, only visible after decryption,
specifies the data contained in the payload. In addition, the Next
Header may also carry an indication on how to process the packet
[I-D.nikander-esp-beet-mode]. The Next Header can point to a dummy
packet, i.e. packets with the Next Header value set to 59 meaning "no
next header". The data following to "no next header" is unstructured
dummy data.
The ability to generate and to receive and ignore dummy packets is
required by [RFC4303]. An implementation can omit ever generating
and sending dummy packets. For interoperability, a minimal ESP
implementation MUST be able to process and discard dummy packets
without indicating an error.
In constrained environments, sending dummy packets may have too much
impact on the device lifetime, in which case dummy packets should not
be generated and sent. On the other hand, Constrained devices
running specific applications that would leak too much information by
not generating and sending dummy packets may implement this
functionality or even implement something similar at the application
layer. Note also that similarly to padding and TFC that can be used
to hide some traffic characteristics (see Section 5), dummy packet
may also reveal some patterns that can be used to identify the
application. For example, an application may send dummy data to hide
some traffic pattern. Suppose such such application sends a 1 byte
data when a change occurs. This results in sending a packet
notifying a change has occurred. Dummy packet may be used to prevent
such information to be leaked by sending a 1 byte packet every second
when the information is not changed. After an upgrade the data
becomes two bytes. At that point, the dummy packets do not hide
anything and having 1 byte regularly versus 2 bytes make even the
identification of the application, version easier to identify. This
generaly makes the use of dummy packets more appropriated on high
speed links.
In some cases, devices are dedicated to a single application or a
single transport protocol, in which case, the Next Header has a fixed
value.
Specific processing indications have not been standardized yet
[I-D.nikander-esp-beet-mode] and is expected to result from an
agreement between the peers. As a result, it SHOULD NOT be part of a
minimal implementation of ESP.
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7. ICV
The ICV depends on the cryptographic suite used. As detailed in
[RFC8221] authentication or authenticated encryption are RECOMMENDED
and as such the ICV field must be present with a size different from
zero. Its length is defined by the security recommendations only.
8. Cryptographic Suites
The recommended algorithms to use are expected to evolve over time
and implementers SHOULD follow the recommendations provided by
[RFC8221] and updates.
This section lists some of the criteria that may be considered to
select an appropriate cryptographic suite. The list is not expected
to be exhaustive and may also evolve over time:
1. Security: Security is the criteria that should be considered
first for the selection of encryption algorithm transform. The
security of encryption algorithm transforms is expected to evolve
over time, and it is of primary importance to follow up-to-date
security guidance and recommendations. The chosen encryption
algorithm MUST NOT be vulnerable or weak (see [RFC8221] for
outdated ciphers). ESP can be used to authenticate only
(ENCR_NULL) or to encrypt the communication. In the latter case,
authenticated encryption (AEAD) is RECOMMENDED [RFC8221].
2. Resilience to nonce re-use: Some transforms -including AES-GCM -
are vulnerable to nonce collision with a given key. While the
generation of the nonce may prevent such collision during a
session, the mechanisms are unlikely to provide such protection
across sleep states or reboot. This causes an issue for devices
that are configured using static keys (called manual keying) and
manual keying should not be used with these encryption
algorithms. When the key is likely to be re-used across reboots,
algorithms that are nonce misuse resistant such as, for example,
AES-SIV [RFC5297], AES-GCM-SIV [RFC8452] or Deoxys-II [DeoxysII]
are RECOMMENDED. Note however that currently none of these are
yet defined for use with ESP.
3. Interoperability: constrained devices usually only implement one
or very few different encryption algorithm transforms. [RFC8221]
takes the life cycle of encryption algorithm transforms and
device manufactoring into consideration in its recommendations
for mandatory-to-implement ("MTI") algorithms.
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4. Power Consumption and Cipher Suite Complexity: Complexity of the
encryption algorithm transform and the energy cost associated
with it are especially important considerations for devices that
have limited resources or are battery powered. The battery life
might determine the lifetime of the entire device. The choice of
a cryptographic function should consider re-using specific
libraries or to take advantage of hardware acceleration provided
by the device. For example, if the device benefits from AES
hardware modules and uses ENCR_AES_CTR, it may prefer AUTH_AES-
XCBC for its authentication. In addition, some devices may also
embed radio modules with hardware acceleration for AES-CCM, in
which case, this transform may be preferred.
5. Power Consumption and Bandwidth Consumption: Reducing the payload
sent may significantly reduce the energy consumption of the
device. Encryption algorithm transforms with low overhead are
strongly preferred. To reduce the overall payload size one may,
for example:
1. Use of counter-based ciphers without fixed block length (e.g.
AES-CTR, or ChaCha20-Poly1305).
2. Use of ciphers with capability of using implicit IVs
[RFC8750].
3. Use of ciphers recommended for IoT [RFC8221].
4. Avoid Padding by sending payload data which are aligned to
the cipher block length - 2 for the ESP trailer.
9. IANA Considerations
There are no IANA consideration for this document.
10. Security Considerations
Security Considerations are those of [RFC4303]. In addition, this
document provided security recommendations and guidance over the
implementation choices for each ESP field.
The security of a communication provided by ESP is closely related to
the security associated with the management of that key. This
usually includes mechanisms to prevent a nonce from repeating, for
example. When a node is provisioned with a session key that is used
across reboot, the implementer MUST ensure that the mechanisms put in
place remain valid across reboot as well.
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It is RECOMMENDED to use ESP in conjunction with key management
protocols such as for example IKEv2 [RFC7296] or minimal IKEv2
[RFC7815]. Such mechanisms are responsible for negotiating fresh
session keys as well as prevent a session key being use beyond its
lifetime. When such mechanisms cannot be implemented, such as when
the the session key is provisioned, the device MUST ensure that keys
are not used beyond their lifetime and that the the key remains used
in compliance will all security requirements across reboots - e.g.
conditions on counters and nonces remains valid.
When a device generates its own key or when random value such as
nonces are generated, the random generation MUST follow [RFC4086].
In addition, [SP-800-90A-Rev-1] provides guidance on how to build
random generators based on deterministic random functions.
11. Privacy Considerations
Preventing the leakage of privacy sensitive information is a hard
problem to solve and usually result in balancing the information
potentially being leaked to the cost associated with the counter
measures. This problem is not inherent to the minimal ESP described
in this document and also concerns the use of ESP in general.
This document targets minimal implementations of ESP and as such
describes some minimalistic way to implement ESP. In some cases,
this may result in potentially revealing privacy sensitive pieces of
information. This document describes these privacy implications so
the implementer can take the appropriate decisions given the
specificities of a given environment and deployment.
The main risks associated with privacy is the ability to identify an
application or a device by analyzing the traffic which is designated
as traffic shaping. As discussed in Section 3, the use in some very
specific context of non randomly generated SPI might in some cases
ease the determination of the device or the application. Similarly,
padding provides limited capabilities to obfuscate the traffic
compared to those provided by TFC. Such consequence on privacy as
detailed in Section 5.
12. Acknowledgment
The authors would like to thank Daniel Palomares, Scott Fluhrer, Tero
Kivinen, Valery Smyslov, Yoav Nir, Michael Richardson, Thomas Peyrin,
Eric Thormarker, Nancy Cam-Winget and Bob Briscoe for their valuable
comments. In particular Scott Fluhrer suggested including the rekey
index in the SPI. Tero Kivinen also provided multiple clarifications
and examples of deployment ESP within constrained devices with their
associated optimizations. Thomas Peyrin Eric Thormarker and Scott
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Fluhrer suggested and clarified the use of transform resilient to
nonce misuse.
13. References
13.1. 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>.
[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>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC7815] Kivinen, T., "Minimal Internet Key Exchange Version 2
(IKEv2) Initiator Implementation", RFC 7815,
DOI 10.17487/RFC7815, March 2016,
<https://www.rfc-editor.org/info/rfc7815>.
[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>.
[RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T.
Kivinen, "Cryptographic Algorithm Implementation
Requirements and Usage Guidance for Encapsulating Security
Payload (ESP) and Authentication Header (AH)", RFC 8221,
DOI 10.17487/RFC8221, October 2017,
<https://www.rfc-editor.org/info/rfc8221>.
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Internet-Draft Minimal ESP September 2022
[RFC8750] Migault, D., Guggemos, T., and Y. Nir, "Implicit
Initialization Vector (IV) for Counter-Based Ciphers in
Encapsulating Security Payload (ESP)", RFC 8750,
DOI 10.17487/RFC8750, March 2020,
<https://www.rfc-editor.org/info/rfc8750>.
13.2. Informative References
[DeoxysII] Jeremy, J. J., Ivica, I. N., Thomas, T. P., and Y. S.
Yannick, "Deoxys v1.41", October 2016,
<https://competitions.cr.yp.to/round3/deoxysv141.pdf>.
[I-D.mglt-ipsecme-diet-esp]
Migault, D., Guggemos, T., Bormann, C., and D. Schinazi,
"ESP Header Compression and Diet-ESP", Work in Progress,
Internet-Draft, draft-mglt-ipsecme-diet-esp-08, 13 May
2022, <https://www.ietf.org/archive/id/draft-mglt-ipsecme-
diet-esp-08.txt>.
[I-D.mglt-ipsecme-ikev2-diet-esp-extension]
Migault, D., Guggemos, T., and D. Schinazi, "Internet Key
Exchange version 2 (IKEv2) extension for the ESP Header
Compression (EHC) Strategy", Work in Progress, Internet-
Draft, draft-mglt-ipsecme-ikev2-diet-esp-extension-02, 13
May 2022, <https://www.ietf.org/archive/id/draft-mglt-
ipsecme-ikev2-diet-esp-extension-02.txt>.
[I-D.nikander-esp-beet-mode]
Nikander, P. and J. Melen, "A Bound End-to-End Tunnel
(BEET) mode for ESP", Work in Progress, Internet-Draft,
draft-nikander-esp-beet-mode-09, 5 August 2008,
<https://www.ietf.org/archive/id/draft-nikander-esp-beet-
mode-09.txt>.
[RFC5297] Harkins, D., "Synthetic Initialization Vector (SIV)
Authenticated Encryption Using the Advanced Encryption
Standard (AES)", RFC 5297, DOI 10.17487/RFC5297, October
2008, <https://www.rfc-editor.org/info/rfc5297>.
[RFC8452] Gueron, S., Langley, A., and Y. Lindell, "AES-GCM-SIV:
Nonce Misuse-Resistant Authenticated Encryption",
RFC 8452, DOI 10.17487/RFC8452, April 2019,
<https://www.rfc-editor.org/info/rfc8452>.
Migault & Guggemos Expires 27 March 2023 [Page 14]
Internet-Draft Minimal ESP September 2022
[SP-800-90A-Rev-1]
Elain, E. B. and J. K. Kelsey, "Recommendation for Random
Number Generation Using Deterministic Random Bit
Generators", <https://csrc.nist.gov/publications/detail/
sp/800-90a/rev-1/final>.
Authors' Addresses
Daniel Migault
Ericsson
8400 boulevard Decarie
Montreal, QC H4P 2N2
Canada
Email: daniel.migault@ericsson.com
Tobias Guggemos
LMU Munich
MNM-Team
Oettingenstr. 67
80538 Munich
Germany
Email: guggemos@mnm-team.org
Migault & Guggemos Expires 27 March 2023 [Page 15]
