[lisp] New draft-ietf-lisp-crypto-03 update

Fri, 04 Dec 2015 10:58:58 -0800 

Brian, Ilari, and I have put in some substantial time for this draft. Changes 
include:

B.1.  Changes to draft-ietf-lisp-crypto-03.txt

   o  Posted December 2015.

   o  Changed cipher suite allocations.  We now have 2 AES-CBC cipher
      suites for compatibility, 3 AES-GCM cipher suites that are faster
      ciphers that include AE and a Chacha20-Poly1305 cipher suite which
      is the fastest but not totally proven/accepted..

   o  Remove 1024-bit DH keys for key exchange.

   o  Make clear that AES and chacha20 ciphers use AEAD so part of
      encrytion/decryption does authentication.

   o  Make it more clear that separate key pairs are used in each
      direction between xTRs.

   o  Indicate that the IV length is different per cipher suite.

   o  Use a counter based IV for every packet for AEAD ciphers.
      Previously text said to use a random number.  But CBC ciphers, use
      a random number.

   o  Indicate that key material is sent in network byte order (big
      endian).

   o  Remove A-bit from Security Type LCAF.  No need to do
      authentication only with the introduction of AEAD ciphers.  These
      ciphers can do authentication.  So you get ciphertext for free.

   o  Remove language that refers to "encryption-key" and "integrity-
      key".  Used term "AEAD-key" that is used by the AEAD cipher suites
      that do encryption and authenticaiton internal to the cipher.

Thanks,
Dino/Brian
Title: Diff: draft-ietf-lisp-crypto-02.txt - draft-ietf-lisp-crypto-03.txt
Content-Type: text/html
< draft-ietf-lisp-crypto-02.txt   draft-ietf-lisp-crypto-03.txt >
Internet Engineering Task Force D. Farinacci Internet Engineering Task Force D. Farinacci
Internet-Draft lispers.net Internet-Draft lispers.net
Intended status: Experimental B. Weis Intended status: Experimental B. Weis
Expires: March 11, 2016 cisco Systems Expires: June 6, 2016 cisco Systems
September 8, 2015 December 4, 2015
LISP Data-Plane Confidentiality LISP Data-Plane Confidentiality
draft-ietf-lisp-crypto-02 draft-ietf-lisp-crypto-03
Abstract Abstract
This document describes a mechanism for encrypting LISP encapsulated This document describes a mechanism for encrypting LISP encapsulated
traffic. The design describes how key exchange is achieved using traffic. The design describes how key exchange is achieved using
existing LISP control-plane mechanisms as well as how to secure the existing LISP control-plane mechanisms as well as how to secure the
LISP data-plane from third-party surveillance attacks. LISP data-plane from third-party surveillance attacks.
Status of This Memo Status of This Memo
skipping to change at page 1, line 34 skipping to change at page 1, line 34
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 March 11, 2016. This Internet-Draft will expire on June 6, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 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
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Diffie-Hellman Key Exchange . . . . . . . . . . . . . . . . . 3 3. Diffie-Hellman Key Exchange . . . . . . . . . . . . . . . . . 3
4. Encoding and Transmitting Key Material . . . . . . . . . . . 4 4. Encoding and Transmitting Key Material . . . . . . . . . . . 4
5. Shared Keys used for the Data-Plane . . . . . . . . . . . . . 7 5. Shared Keys used for the Data-Plane . . . . . . . . . . . . . 7
6. Data-Plane Operation . . . . . . . . . . . . . . . . . . . . 8 6. Data-Plane Operation . . . . . . . . . . . . . . . . . . . . 9
7. Procedures for Encryption and Decryption . . . . . . . . . . 10 7. Procedures for Encryption and Decryption . . . . . . . . . . 10
8. Dynamic Rekeying . . . . . . . . . . . . . . . . . . . . . . 11 8. Dynamic Rekeying . . . . . . . . . . . . . . . . . . . . . . 11
9. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 12 9. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 12
10. Security Considerations . . . . . . . . . . . . . . . . . . . 12 10. Security Considerations . . . . . . . . . . . . . . . . . . . 12
10.1. SAAG Support . . . . . . . . . . . . . . . . . . . . . . 12 10.1. SAAG Support . . . . . . . . . . . . . . . . . . . . . . 12
10.2. LISP-Crypto Security Threats . . . . . . . . . . . . . . 12 10.2. LISP-Crypto Security Threats . . . . . . . . . . . . . . 12
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
12.1. Normative References . . . . . . . . . . . . . . . . . . 13 12.1. Normative References . . . . . . . . . . . . . . . . . . 13
12.2. Informative References . . . . . . . . . . . . . . . . . 14 12.2. Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 15 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 15
Appendix B. Document Change Log . . . . . . . . . . . . . . . . 15 Appendix B. Document Change Log . . . . . . . . . . . . . . . . 15
B.1. Changes to draft-ietf-lisp-crypto-01.txt . . . . . . . . 15 B.1. Changes to draft-ietf-lisp-crypto-03.txt . . . . . . . . 15
B.2. Changes to draft-ietf-lisp-crypto-01.txt . . . . . . . . 15 B.2. Changes to draft-ietf-lisp-crypto-02.txt . . . . . . . . 16
B.3. Changes to draft-ietf-lisp-crypto-00.txt . . . . . . . . 15 B.3. Changes to draft-ietf-lisp-crypto-01.txt . . . . . . . . 16
B.4. Changes to draft-farinacci-lisp-crypto-01.txt . . . . . . 15 B.4. Changes to draft-ietf-lisp-crypto-00.txt . . . . . . . . 16
B.5. Changes to draft-farinacci-lisp-crypto-00.txt . . . . . . 16 B.5. Changes to draft-farinacci-lisp-crypto-01.txt . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 B.6. Changes to draft-farinacci-lisp-crypto-00.txt . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
The Locator/ID Separation Protocol [RFC6830] defines a set of The Locator/ID Separation Protocol [RFC6830] defines a set of
functions for routers to exchange information used to map from non- functions for routers to exchange information used to map from non-
routable Endpoint Identifiers (EIDs) to routable Routing Locators routable Endpoint Identifiers (EIDs) to routable Routing Locators
(RLOCs). LISP ITRs and PITRs encapsulate packets to ETRs and RTRs. (RLOCs). LISP ITRs and PITRs encapsulate packets to ETRs and RTRs.
Packets that arrive at the ITR or PITR are typically not modified. Packets that arrive at the ITR or PITR are typically not modified.
Which means no protection or privacy of the data is added. If the Which means no protection or privacy of the data is added. If the
source host encrypts the data stream then the encapsulated packets source host encrypts the data stream then the encapsulated packets
skipping to change at page 3, line 37 skipping to change at page 3, line 40
ITR needs to obtain the RLOC of an ETR, it will get security material ITR needs to obtain the RLOC of an ETR, it will get security material
to compute a shared secret with the ETR. to compute a shared secret with the ETR.
The ITR can compute 3 shared-secrets per ETR the ITR is encapsulating The ITR can compute 3 shared-secrets per ETR the ITR is encapsulating
to. And when the ITR encrypts a packet before encapsulation, it will to. And when the ITR encrypts a packet before encapsulation, it will
identify the key it used for the crypto calculation so the ETR knows identify the key it used for the crypto calculation so the ETR knows
which key to use for decrypting the packet after decapsulation. By which key to use for decrypting the packet after decapsulation. By
using key-ids in the LISP header, we can also get real-time rekeying using key-ids in the LISP header, we can also get real-time rekeying
functionality. functionality.
When an ETR (when it is also an ITR) encapsulates packets to this ITR
(when it is also an ETR), a separate key exchange and shared-secret
computation is performed. The key management described in this
documemnt is unidirectional from the ITR (the encapsulator) to the
ETR (the decapsultor).
3. Diffie-Hellman Key Exchange 3. Diffie-Hellman Key Exchange
LISP will use a Diffie-Hellman [RFC2631] key exchange sequence and LISP will use a Diffie-Hellman [RFC2631] key exchange sequence and
computation for computing a shared secret. The Diffie-Hellman computation for computing a shared secret. The Diffie-Hellman
parameters will be passed via Cipher Suite code-points in Map-Request parameters will be passed via Cipher Suite code-points in Map-Request
and Map-Reply messages. and Map-Reply messages.
Here is a brief description how Diff-Hellman works: Here is a brief description how Diff-Hellman works:
+----------------------------+---------+----------------------------+ +----------------------------+---------+----------------------------+
skipping to change at page 5, line 12 skipping to change at page 5, line 12
Map-Reply messages. Diffie-Hellman parameters are encoded in the Map-Reply messages. Diffie-Hellman parameters are encoded in the
LISP Security Type LCAF [LCAF]. LISP Security Type LCAF [LCAF].
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI = 16387 | Rsvd1 | Flags | | AFI = 16387 | Rsvd1 | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 11 | Rsvd2 | 6 + n | | Type = 11 | Rsvd2 | 6 + n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key Count | Rsvd3 |A| Cipher Suite| Rsvd4 |R| | Key Count | Rsvd3 | Cipher Suite | Rsvd4 |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Key Length | Public Key Material ... | | Key Length | Public Key Material ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Public Key Material | | ... Public Key Material |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI = x | Locator Address ... | | AFI = x | Locator Address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Cipher Suite field contains DH Key Exchange and Cipher/Hash Functions Cipher Suite field contains DH Key Exchange and Cipher/Hash Functions
The 'Key Count' field encodes the number of {'Key-Length', 'Key- The 'Key Count' field encodes the number of {'Key-Length', 'Key-
Material'} fields included in the encoded LCAF. The maximum number Material'} fields included in the encoded LCAF. The maximum number
of keys that can be encoded are 3, each identified by key-id 1, of keys that can be encoded are 3, each identified by key-id 1,
followed by key-id 2, an finally key-id 3. followed by key-id 2, an finally key-id 3.
The 'R' bit is not used for this use-case of the Security Type LCAF The 'R' bit is not used for this use-case of the Security Type LCAF
but is reserved for [LISP-DDT] security. but is reserved for [LISP-DDT] security.
When the A-bit is set, it indicates that Authentication only is Cipher Suite 0:
performed according to the Integrity hash function defined in the Reserved
Cipher Suites. That is an encapsulator will perform an Integrity
computation over an unencrypted packet and include an ICV value.
Since the packet contains no ciphertext, there is no IV value
included in the message. The 7-bit 'Cipher Suite' field defines the
following code-points:
Cipher Suite 0: Cipher Suite 1:
Reserved Diffie-Hellman Group: 2048-bit MODP [RFC3526]
Encryption: AES with 128-bit keys in CBC mode [AES-CBC]
Integrity: Integrated with [AES-CBC] AEAD [RFC5116] encryption
IV length: 16 bytes
Cipher Suite 1: Cipher Suite 2:
Diffie-Hellman Group: 1024-bit Modular Exponential (MODP) [RFC2409] Diffie-Hellman Group: 256-bit Elliptic-Curve 25519 [CURVE25519]
Encryption: AES with 128-bit keys in CBC mode [AES-CBC] Encryption: AES with 128-bit keys in CBC mode [AES-CBC]
Integrity: HMAC-SHA1-96 [RFC2404] Integrity: HMAC-SHA1-96 [RFC2404]
IV length: 16 bytes
Cipher Suite 2: Cipher Suite 3:
Diffie-Hellman Group: 2048-bit MODP [RFC3526] Diffie-Hellman Group: 2048-bit MODP [RFC3526]
Encryption: AES with 128-bit keys in CBC mode [AES-CBC] Encryption: AES with 128-bit keys in GCM mode [AES-GCM]
Integrity: HMAC-SHA1-96 [RFC2404] Integrity: Integrated with [AES-GCM] AEAD [RFC5116] encryption
IV length: 12 bytes
Cipher Suite 3: Cipher Suite 4:
Diffie-Hellman Group: 3072-bit MODP [RFC3526] Diffie-Hellman Group: 3072-bit MODP [RFC3526]
Encryption: AES with 128-bit keys in CBC mode [AES-CBC] Encryption: AES with 128-bit keys in GCM mode [AES-GCM]
Integrity: HMAC-SHA1-96 [RFC2404] Integrity: Integrated with [AES-GCM] AEAD [RFC5116] encryption
IV length: 12 bytes
Cipher Suite 4: Cipher Suite 5:
Diffie-Hellman Group: 256-bit Elliptic-Curve 25519 [CURVE25519] Diffie-Hellman Group: 256-bit Elliptic-Curve 25519 [CURVE25519]
Encryption: AES with 128-bit keys in CBC mode [AES-CBC] Encryption: AES with 128-bit keys in GCM mode [AES-GCM]
Integrity: HMAC-SHA1-96 [RFC2404] Integrity: Integrated with [AES-GCM] AEAD [RFC5116] encryption
IV length: 12 bytes
Cipher Suite 5: Cipher Suite 6:
Diffie-Hellman Group: 256-bit Elliptic-Curve 25519 [CURVE25519] Diffie-Hellman Group: 256-bit Elliptic-Curve 25519 [CURVE25519]
Encryption: Chacha20-Poly1305 [CHACHA-POLY] Encryption/Integrity: Chacha20-Poly1305 [CHACHA-POLY] [RFC7539]
Integrity: HMAC-SHA1-96 [RFC2404] Integrity: Integrated with Chacha20-Poly1305 AEAD [RFC1116] encryption
IV length: 8 bytes
The "Public Key Material" field contains the public key generated by The "Public Key Material" field contains the public key generated by
one of the Cipher Suites defined above. The length of the key in one of the Cipher Suites defined above. The length of the key in
octets is encoded in the "Key Length" field. octets is encoded in the "Key Length" field.
When an ITR or PITR send a Map-Request, they will encode their own When an ITR or PITR send a Map-Request, they will encode their own
RLOC in the Security Type LCAF format within the ITR-RLOCs field. RLOC in the Security Type LCAF format within the ITR-RLOCs field.
When a ETR or RTR sends a Map-Reply, they will encode their RLOCs in When a ETR or RTR sends a Map-Reply, they will encode their RLOCs in
Security Type LCAF format within the RLOC-record field of each EID- Security Type LCAF format within the RLOC-record field of each EID-
record supplied. record supplied.
skipping to change at page 7, line 16 skipping to change at page 7, line 28
5. Shared Keys used for the Data-Plane 5. Shared Keys used for the Data-Plane
When an ITR or PITR receives a Map-Reply accepting the Cipher Suite When an ITR or PITR receives a Map-Reply accepting the Cipher Suite
sent in the Map-Request, it is ready to create data plane keys. The sent in the Map-Request, it is ready to create data plane keys. The
same process is followed by the ETR or RTR returning the Map-Reply. same process is followed by the ETR or RTR returning the Map-Reply.
The first step is to create a shared secret, using the peer's shared The first step is to create a shared secret, using the peer's shared
Diffie-Hellman Public Key Material combined with device's own private Diffie-Hellman Public Key Material combined with device's own private
keying material as described in Section 3. The Diffie-Hellman group keying material as described in Section 3. The Diffie-Hellman group
used is defined in the Cipher Suite sent in the Map-Request and used is defined in the cipher suite sent in the Map-Request and
copied into the Map-Reply. copied into the Map-Reply.
The resulting shared secret is used to compute Encryption and The resulting shared secret is used to compute an AEAD-key for the
Integrity keys for the algorithms specified in the Cipher Suite. A algorithms specified in the cipher suite. A Key Derivation Function
Key Derivation Function (KDF) in counter mode as specified by (KDF) in counter mode as specified by [NIST-SP800-108] is used to
[NIST-SP800-108] is used to generate the data-plane keys. The amount generate the data-plane keys. The amount of keying material that is
of keying material that is derived depends on the algorithms in the derived depends on the algorithms in the cipher suite.
cipher suite.
The inputs to the KDF are as follows: The inputs to the KDF are as follows:
o KDF function. This is HMAC-SHA-256. o KDF function. This is HMAC-SHA-256.
o A key for the KDF function. This is the most significant 16 o A key for the KDF function. This is the computed Diffie-Hellman
octets of the computed Diffie-Hellman shared secret. shared secret.
o Context that binds the use of the data-plane keys to this session. o Context that binds the use of the data-plane keys to this session.
The context is made up of the following fields, which are The context is made up of the following fields, which are
concatenated and provided as the data to be acted upon by the KDF concatenated and provided as the data to be acted upon by the KDF
function. function.
Context: Context:
o A counter, represented as a two-octet value in network-byte order. o A counter, represented as a two-octet value in network-byte order.
o The null-terminated string "lisp-crypto". o The null-terminated string "lisp-crypto".
o The ITR's nonce from the the Map-Request the Cipher Suite was o The ITR's nonce from the the Map-Request the cipher suite was
included in. included in.
o The number of bits of keying material required (L), represented as o The number of bits of keying material required (L), represented as
a two-octet value in network byte order. a two-octet value in network byte order.
The counter value in the context is first set to 1. When the amount The counter value in the context is first set to 1. When the amount
of keying material exceeds the number of bits returned by the KDF of keying material exceeds the number of bits returned by the KDF
function, then the KDF function is called again with the same inputs function, then the KDF function is called again with the same inputs
except that the counter increments for each call. When enough keying except that the counter increments for each call. When enough keying
material is returned, it is concatenated and used to create keys. material is returned, it is concatenated and used to create keys.
skipping to change at page 8, line 39 skipping to change at page 8, line 50
key-material-2 = HMAC-SHA-256(dh-shared-secret, context) key-material-2 = HMAC-SHA-256(dh-shared-secret, context)
where: context = 0x0002 || "lisp-crypto" || <itr-nonce> || 0x0200 where: context = 0x0002 || "lisp-crypto" || <itr-nonce> || 0x0200
key-material = key-material-1 || key-material-2 key-material = key-material-1 || key-material-2
If the key-material is longer than the required number of bits (L), If the key-material is longer than the required number of bits (L),
then only the most significant L bits are used. then only the most significant L bits are used.
From the derived key-material, the most significant bits are used for From the derived key-material, the most significant 256 bits are used
the Encryption key, and least significant bits are used for the for the AEAD-key by AEAD ciphers. The 256-bit AEAD-key is divided
Integrity key. For example, if the Cipher Suite contains both AES into a 128-bit encryption key and a 128-bit integrity-check key
with 128-bit keys and HMAC-SHA1-96, the most significant 128 bits internal to the cipher used by the ITR.
become the ITR's data-plane encryption key, and the next 128-bit
become the ITR's Integrity key.
6. Data-Plane Operation 6. Data-Plane Operation
The LISP encapsulation header [RFC6830] requires changes to encode The LISP encapsulation header [RFC6830] requires changes to encode
the key-id for the key being used for encryption. the key-id for the key being used for encryption.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 4341 | / | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum | \ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L / |N|L|E|V|I|P|K|K| Nonce/Map-Version | \ L / |N|L|E|V|I|P|K|K| Nonce/Map-Version | \ \
I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | AD
S \ | Instance ID/Locator-Status-Bits | | S \ | Instance ID/Locator-Status-Bits | | /
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Initialization Vector (IV) | I | Initialization Vector (IV) | I
E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ C E +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ C
n / | | V n / | | V
c | | | c | | |
r | Packet Payload with EID Header ... | | r | Packet Payload with EID Header ... | |
y | | | y | | |
p \ | | / p \ | | /
t +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ t +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Integrity Check Value (ICV) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
K-bits indicate when packet is encrypted and which key used K-bits indicate when packet is encrypted and which key used
When the KK bits are 00, the encapsulated packet is not encrypted. When the KK bits are 00, the encapsulated packet is not encrypted.
When the value of the KK bits are 1, 2, or 3, it encodes the key-id When the value of the KK bits are 1, 2, or 3, it encodes the key-id
of the secret keys computed during the Diffie-Hellman Map-Request/ of the secret keys computed during the Diffie-Hellman Map-Request/
Map-Reply exchange. When the KK bits are not 0, the payload is Map-Reply exchange. When the KK bits are not 0, the payload is
prepended with an Initialization Vector (IV) and appended with an prepended with an Initialization Vector (IV). The length of the IV
Integrity Check Value (ICV). The length of the IV and ICV fields field is based on the cipher suite used. Since all cipher suites
depend on the Cipher Suite negotiated in the control-plane. defined in this document do Authenticated Encryption (AEAD), an ICV
field does not need to be present in the packet since it is included
in the ciphertext. The Additional Data (AD) used for the ICV is
shown above and includes the LISP header, the IV field and the packet
payload.
When an ITR or PITR receives a packet to be encapsulated, they will When an ITR or PITR receives a packet to be encapsulated, they will
first decide what key to use, encode the key-id into the LISP header, first decide what key to use, encode the key-id into the LISP header,
and use that key to encrypt all packet data that follows the LISP and use that key to encrypt all packet data that follows the LISP
header. Therefore, the outer header, UDP header, and LISP header header. Therefore, the outer header, UDP header, and LISP header
travel as plaintext. travel as plaintext.
There is an open working group item to discuss if the data There is an open working group item to discuss if the data
encapsulation header needs change for encryption or any new encapsulation header needs change for encryption or any new
applications. This draft proposes changes to the existing header so applications. This draft proposes changes to the existing header so
experimentation can continue without making large changes to the experimentation can continue without making large changes to the
data-plane at this time. data-plane at this time.
7. Procedures for Encryption and Decryption 7. Procedures for Encryption and Decryption
When an ITR, PITR, or RTR encapsulate a packet and have already When an ITR, PITR, or RTR encapsulate a packet and have already
computed an encryption-key and integrity-key (detailed in section computed an AEAD-key (detailed in section Section 5) that is
Section 5) that is associated with a destination RLOC, the following associated with a destination RLOC, the following encryption and
encryption and encapsulation procedures are performed: encapsulation procedures are performed:
1. The encapsulator creates a random number used as the IV. 1. The encapsulator creates an IV and prepends the IV value to the
Prepends the IV value to the packet being encapsulated. The IV packet being encapsulated. For GCM and Chacha cipher suites, the
is incremented for every packet sent to the destination RLOC. IV is incremented for every packet (beginning with a value of 1
in the first packet) and sent to the destination RLOC. For CBC
cipher suites, the IV is a new random number for every packet
sent to the destination RLOC. For the Chacha cipher suite, the
IV is an 8-byte random value that is appended to a 4-byte counter
that is incremented for every packet (beginning with a value of 1
in the first packet).
2. Next encrypt with cipher function AES-CBC using the encryption- 2. Next encrypt with cipher function AES or Chacha20 using the AEAD-
key over the packet payload. This does not include the IV. The key over the packet payload following the AEAD specification
IV must be transmitted as plaintext so the decrypter can use it referenced in the cipher suite definition. This does not include
as input to the decryption cipher. The payload should be padded the IV. The IV must be transmitted as plaintext so the decrypter
to an integral number of bytes a block cipher may require. can use it as input to the decryption cipher. The payload should
be padded to an integral number of bytes a block cipher may
require. The result of the AEAD operation may contain an ICV,
the size of which is defined by the referenced AEAD
specification. Note that the AD (i.e. the LISP header exactly as
will be prepended in the next step and the IV) must be given to
the AEAD encryption function as the "associated data" argument.
3. Prepend the LISP header. The key-id field of the LISP header is 3. Prepend the LISP header. The key-id field of the LISP header is
set to the key-id value that corresponds to key-pair used for the set to the key-id value that corresponds to key-pair used for the
encryption cipher and for the ICV hash. encryption cipher.
4. Next compute the ICV value by hashing the packet (which includes
the LISP header, the IV, and the packet payload) with the HMAC-
SHA1 function using the integrity-key. The resulting ICV value
is appended to the packet. The ICV is not ciphertext so a fast
integrity check can be performed without decryption at the
receiver.
5. Lastly, prepend the UDP header and outer IP header onto the 4. Lastly, prepend the UDP header and outer IP header onto the
encrypted packet and send packet to destination RLOC. encrypted packet and send packet to destination RLOC.
When an ETR, PETR, or RTR receive an encapsulated packet, the When an ETR, PETR, or RTR receive an encapsulated packet, the
following decapsulation and decryption procedures are performed: following decapsulation and decryption procedures are performed:
1. The outer IP header and UDP header are stripped from the start of 1. The outer IP header, UDP header, LISP header, and IV field are
the packet and the ICV is stripped from the end of the packet. stripped from the start of the packet. The LISP header and IV
are retained and given to the AEAD decryption operation as the
2. Next the ICV is computed by running the Integrity function from "associated data" argument.
the cipher suite using the integrity-key over the packet (which
includes the LISP header, the IV and packet payload) using the
integrity-key. If the result does not match the ICV value from
the packet, the packet was been tampered with, and is dropped,
and an optional log message may be issued. The integrity-key is
obtained from a local-cache associated with the key-id value from
the LISP header.
3. If the hashed result matches the ICV value from the packet, then
the LISP header is stripped and decryption occurs over the packet
payload using the plaintext IV in the packet.
4. The IV is stripped from the packet.
5. The packet is decrypted using the encryption-key and the IV from 2. The packet is decrypted using the AEAD-key and the IV from the
the packet. The encryption-key is obtained from a local-cache packet. The AEAD-key is obtained from a local-cache associated
associated with the key-id value from the LISP header. The with the key-id value from the LISP header. The result of the
result of the decryption function is a plaintext packet payload. decryption function is a plaintext packet payload if the cipher
returned a verified ICV. Otherwise, the packet has been tampered
with, is dropped, and an optional log message may be issued. If
the AEAD specification included an ICV, the AEAD decryption
function will locate the ICV in the ciphertext and compare it to
a version of the ICV that the AEAD decryption function computes.
If the computed ICV is different than the ICV located in the
ciphertext, then it will be considered tampered.
6. The resulting packet is forwarded to the destination EID. 3. If the packet was not tampered with, the decrypted packet is
forwarded to the destination EID.
8. Dynamic Rekeying 8. Dynamic Rekeying
Since multiple keys can be encoded in both control and data messages, Since multiple keys can be encoded in both control and data messages,
an ITR can encapsulate and encrypt with a specific key while it is an ITR can encapsulate and encrypt with a specific key while it is
negotiating other keys with the same ETR. Soon as an ETR or RTR negotiating other keys with the same ETR. Soon as an ETR or RTR
returns a Map-Reply, it should be prepared to decapsulate and decrypt returns a Map-Reply, it should be prepared to decapsulate and decrypt
using the new keys computed with the new Diffie-Hellman parameters using the new keys computed with the new Diffie-Hellman parameters
received in the Map-Request and returned in the Map-Reply. received in the Map-Request and returned in the Map-Reply.
skipping to change at page 12, line 18 skipping to change at page 12, line 23
9. Future Work 9. Future Work
For performance considerations, newer Elliptic-Curve Diffie-Hellman For performance considerations, newer Elliptic-Curve Diffie-Hellman
(ECDH) groups can be used as specified in [RFC4492] and [RFC6090] to (ECDH) groups can be used as specified in [RFC4492] and [RFC6090] to
reduce CPU cycles required to compute shared secret keys. reduce CPU cycles required to compute shared secret keys.
For better security considerations as well as to be able to build For better security considerations as well as to be able to build
faster software implementations, newer approaches to ciphers and faster software implementations, newer approaches to ciphers and
authentication methods will be researched and tested. Some examples authentication methods will be researched and tested. Some examples
are chacha20 and poly1305 [CHACHA-POLY]. are Chacha20 and Poly1305 [CHACHA-POLY] [RFC7539].
10. Security Considerations 10. Security Considerations
10.1. SAAG Support 10.1. SAAG Support
The LISP working group has and will continue to seek help from the The LISP working group has and will continue to seek help from the
SAAG working group for security advice. The SAAG has been involved SAAG working group for security advice. The SAAG has been involved
early in the design process so they have early input and review. early in the design process so they have early input and review.
10.2. LISP-Crypto Security Threats 10.2. LISP-Crypto Security Threats
skipping to change at page 14, line 15 skipping to change at page 14, line 19
[RFC6090] McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic [RFC6090] McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic
Curve Cryptography Algorithms", RFC 6090, Curve Cryptography Algorithms", RFC 6090,
DOI 10.17487/RFC6090, February 2011, DOI 10.17487/RFC6090, February 2011,
<http://www.rfc-editor.org/info/rfc6090>. <http://www.rfc-editor.org/info/rfc6090>.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
Locator/ID Separation Protocol (LISP)", RFC 6830, Locator/ID Separation Protocol (LISP)", RFC 6830,
DOI 10.17487/RFC6830, January 2013, DOI 10.17487/RFC6830, January 2013,
<http://www.rfc-editor.org/info/rfc6830>. <http://www.rfc-editor.org/info/rfc6830>.
[RFC7539] Nir, Y. and A. Langley, "ChaCha20 and Poly1305 for IETF
Protocols", RFC 7539, DOI 10.17487/RFC7539, May 2015,
<http://www.rfc-editor.org/info/rfc7539>.
12.2. Informative References 12.2. Informative References
[AES-CBC] McGrew, D., Foley, J., and K. Paterson, "Authenticated [AES-CBC] McGrew, D., Foley, J., and K. Paterson, "Authenticated
Encryption with AES-CBC and HMAC-SHA", draft-mcgrew-aead- Encryption with AES-CBC and HMAC-SHA", draft-mcgrew-aead-
aes-cbc-hmac-sha2-05.txt (work in progress). aes-cbc-hmac-sha2-05.txt (work in progress).
[CHACHA-POLY] [CHACHA-POLY]
Langley, A., "ChaCha20 and Poly1305 based Cipher Suites Langley, A., "ChaCha20 and Poly1305 based Cipher Suites
for TLS", draft-agl-tls-chacha20poly1305-00 (work in for TLS", draft-agl-tls-chacha20poly1305-00 (work in
progress). progress).
skipping to change at page 15, line 7 skipping to change at page 15, line 17
"LISP-Secuirty (LISP-SEC)", draft-ietf-lisp-sec-06 (work "LISP-Secuirty (LISP-SEC)", draft-ietf-lisp-sec-06 (work
in progress). in progress).
[NIST-SP800-108] [NIST-SP800-108]
"National Institute of Standards and Technology, "National Institute of Standards and Technology,
"Recommendation for Key Derivation Using Pseudorandom "Recommendation for Key Derivation Using Pseudorandom
Functions NIST SP800-108"", NIST SP 800-108, October 2009. Functions NIST SP800-108"", NIST SP 800-108, October 2009.
Appendix A. Acknowledgments Appendix A. Acknowledgments
The author would like to thank Dan Harkins, Joel Halpern, Fabio The authors would like to thank Dan Harkins, Joel Halpern, Fabio
Maino, Ed Lopez, Roger Jorgensen, Watson Ladd, and Ilari Liusvaara Maino, Ed Lopez, Roger Jorgensen, and Watson Ladd for their interest,
for their interest, suggestions, and discussions about LISP data- suggestions, and discussions about LISP data-plane security.
plane security.
The authors would like to give a special thank you to Ilari Liusvaara
for his extensive commentary and discussion. He has contributed his
security expertise to make lisp-crypto as secure as the state of the
art in cryptography.
In addition, the support and suggestions from the SAAG working group In addition, the support and suggestions from the SAAG working group
were helpful and appreciative. were helpful and appreciative.
Appendix B. Document Change Log Appendix B. Document Change Log
B.1. Changes to draft-ietf-lisp-crypto-01.txt B.1. Changes to draft-ietf-lisp-crypto-03.txt
o Posted December 2015.
o Changed cipher suite allocations. We now have 2 AES-CBC cipher
suites for compatibility, 3 AES-GCM cipher suites that are faster
ciphers that include AE and a Chacha20-Poly1305 cipher suite which
is the fastest but not totally proven/accepted..
o Remove 1024-bit DH keys for key exchange.
o Make clear that AES and chacha20 ciphers use AEAD so part of
encrytion/decryption does authentication.
o Make it more clear that separate key pairs are used in each
direction between xTRs.
o Indicate that the IV length is different per cipher suite.
o Use a counter based IV for every packet for AEAD ciphers.
Previously text said to use a random number. But CBC ciphers, use
a random number.
o Indicate that key material is sent in network byte order (big
endian).
o Remove A-bit from Security Type LCAF. No need to do
authentication only with the introduction of AEAD ciphers. These
ciphers can do authentication. So you get ciphertext for free.
o Remove language that refers to "encryption-key" and "integrity-
key". Used term "AEAD-key" that is used by the AEAD cipher suites
that do encryption and authenticaiton internal to the cipher.
B.2. Changes to draft-ietf-lisp-crypto-02.txt
o Posted September 2015. o Posted September 2015.
o Add cipher suite for Elliptic Curve 25519 DH exchange. o Add cipher suite for Elliptic Curve 25519 DH exchange.
o Add cipher suite for Chacha20/poly1305 ciphers. o Add cipher suite for Chacha20/Poly1305 ciphers.
B.2. Changes to draft-ietf-lisp-crypto-01.txt B.3. Changes to draft-ietf-lisp-crypto-01.txt
o Posted May 2015. o Posted May 2015.
o Create cipher suites and encode them in the Security LCAF. o Create cipher suites and encode them in the Security LCAF.
o Add IV to beginning of packet header and ICV to end of packet. o Add IV to beginning of packet header and ICV to end of packet.
o AEAD procedures are now part of encrpytion process. o AEAD procedures are now part of encrpytion process.
B.3. Changes to draft-ietf-lisp-crypto-00.txt B.4. Changes to draft-ietf-lisp-crypto-00.txt
o Posted January 2015. o Posted January 2015.
o Changing draft-farinacci-lisp-crypto-01 to draft-ietf-lisp-crypto- o Changing draft-farinacci-lisp-crypto-01 to draft-ietf-lisp-crypto-
00. This draft has become a working group document 00. This draft has become a working group document
o Add text to indicate the working group may work on a new data o Add text to indicate the working group may work on a new data
encapsulation header format for data-plane encryption. encapsulation header format for data-plane encryption.
B.4. Changes to draft-farinacci-lisp-crypto-01.txt B.5. Changes to draft-farinacci-lisp-crypto-01.txt
o Posted July 2014. o Posted July 2014.
o Add Group-ID to the encoding format of Key Material in a Security o Add Group-ID to the encoding format of Key Material in a Security
Type LCAF and modify the IANA Considerations so this draft can use Type LCAF and modify the IANA Considerations so this draft can use
key exchange parameters from the IANA registry. key exchange parameters from the IANA registry.
o Indicate that the R-bit in the Security Type LCAF is not used by o Indicate that the R-bit in the Security Type LCAF is not used by
lisp-crypto. lisp-crypto.
skipping to change at page 16, line 23 skipping to change at page 17, line 23
process. process.
o Add text indicating that when RLOC-probing is used for RLOC o Add text indicating that when RLOC-probing is used for RLOC
reachability purposes and rekeying is not desired, that the same reachability purposes and rekeying is not desired, that the same
key exchange parameters should be used so a reallocation of a key exchange parameters should be used so a reallocation of a
pubic key does not happen at the ETR. pubic key does not happen at the ETR.
o Add text to indicate that ECDH can be used to reduce CPU o Add text to indicate that ECDH can be used to reduce CPU
requirements for computing shared secret-keys. requirements for computing shared secret-keys.
B.5. Changes to draft-farinacci-lisp-crypto-00.txt B.6. Changes to draft-farinacci-lisp-crypto-00.txt
o Initial draft posted February 2014. o Initial draft posted February 2014.
Authors' Addresses Authors' Addresses
Dino Farinacci Dino Farinacci
lispers.net lispers.net
San Jose, California 95120 San Jose, California 95120
USA USA
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