ISO/IEC 13157-2:2016

Information technology - Telecommunications and information exchange between systems - NFC Security - Part 2: NFC-SEC cryptography standard using ECDH and AES

ISO/IEC 13157-2:2016 specifies the message contents and the cryptographic methods for PID 01. ISO/IEC 13157-2:2016 specifies cryptographic mechanisms that use the Elliptic Curves Diffie-Hellman (ECDH) protocol for key agreement and the AES algorithm for data encryption and integrity.

Technologies de l'information — Téléinformatique — Sécurité NFC — Partie 2: Norme de cryptographie NFC-SEC utilisant ECDH et AES

General Information

• Status: Published
• Publication Date: 28-Mar-2016
• ICS: 35.110 - Networking
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 9093 - International Standard confirmed
• Start Date: 23-May-2025
• Completion Date: 30-Oct-2025

Relations

• Revises: ISO/IEC 13157-2:2010 - Information technology - Telecommunications and information exchange between systems - NFC Security - - Part 2: NFC-SEC cryptography standard using ECDH and AES
• Effective Date: 02-Apr-2016

Overview

ISO/IEC 13157-2:2016 defines the NFC-SEC cryptography mechanisms that enable secure Near Field Communication (NFC) between devices that do not share a prior secret. The standard specifies message formats (PID 01) and cryptographic methods based on Elliptic Curve Diffie–Hellman (ECDH) for key agreement and AES for data encryption and integrity. It is part of the NFC Security series and is intended to be used together with the protocol services in ISO/IEC 13157-1.

Key Topics

• ECDH key agreement
  • Use of elliptic-curve public/private key pairs to derive a shared secret between NFC peers.
  • Includes EC key pair generation, public-key validation, and shared-secret derivation.
  • References specific curve usage (e.g., Curve P-192 noted in the specification).
• AES-based confidentiality and integrity
  • AES algorithms are used for encryption and message integrity.
  • Annex A specifies AES-XCBC-PRF-128 and AES-XCBC-MAC-96 for MAC and PRF operations.
• Key Derivation and Usage
  • Key Derivation Functions (KDFs) defined for SSE (Shared Secret Service) and SCH (Secure Channel Service).
  • Separation of encryption (KE) and integrity (KI) keys and explicit key confirmation procedures.
• Protocol and message details
  • Defines PID 01 message contents, nonce usage, initial counter/IV selection for AES modes, message sequence integrity, and required data conversions (integer/point to octet-string conversions).
• Conformance and normative references
  • Conformant implementations must follow ISO/IEC 13157-1 and referenced cryptographic standards (e.g., ISO/IEC 15946-1, ISO/IEC 18031).

Applications

ISO/IEC 13157-2:2016 is applicable wherever NFC devices need to establish a secure channel without prior shared keys. Typical applications include:

• Mobile payments and wallets (secure pairing and transaction encryption)
• Access control and secure identity transfer (e.g., badges, tickets)
• Secure peer-to-peer data exchange between smartphones, wearables, and IoT devices
• NFC-enabled readers and tags that require authenticated, confidential sessions

Primary users and implementers:

• NFC device manufacturers and firmware developers
• Security architects and protocol engineers
• Payment system integrators and access-control solution providers
• Test labs and certification bodies validating NFC-SEC conformance

Related standards

• ISO/IEC 13157-1 (NFC-SEC services and protocol) - mandatory for protocol-level conformance
• ISO/IEC 13157 series (Parts 3–5) - other cryptography and authentication options (e.g., ECDH-256, AES-GCM)
• ISO/IEC 15946-1 (elliptic-curve cryptography), ISO/IEC 18031 (random bit generation), ISO/IEC 10116 (block cipher modes)

Keywords: ISO/IEC 13157-2:2016, NFC security, NFC-SEC, ECDH, AES, AES-XCBC, key agreement, secure channel, NFC encryption, key derivation.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 13157-2
Second edition
2016-04-01
Information technology —
Telecommunications and information
exchange between systems — NFC
Security —
Part 2:
NFC-SEC cryptography standard using
ECDH and AES
Technologies de l’information — Téléinformatique — Sécurité NFC —
Partie 2: Norme de cryptographie NFC-SEC utilisant ECDH et AES
Reference number
©
ISO/IEC 2016
© ISO/IEC 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO/IEC 2016 – All rights reserved

Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Conformance . 1
3 Normative references . 1
4 Terms and definitions . 2
5 Conventions and notations . 2
5.1 Concatenation . 2
5.2 Hexadecimal numbers . 2
6 Acronyms . 2
7 General . 3
8 Protocol Identifier (PID) . 3
9 Primitives . 3
9.1 Key agreement . 4
9.1.1 Curve P-192 . 4
9.1.2 EC Key Pair Generation Primitive . 4
9.1.3 EC Public key validation . 4
9.1.4 ECDH secret value derivation Primitive . 4
9.1.5 Random nonces . 4
9.2 Key Derivation Functions . 5
9.2.1 KDF for the SSE . 5
9.2.2 KDF for the SCH . 5
9.3 Key Usage . 5
9.4 Key Confirmation . 6
9.4.1 Key confirmation tag generation . 6
9.4.2 Key confirmation tag verification . 6
9.5 Data Encryption . 6
9.5.1 Initial value of counter (IV) . 6
9.5.2 Encryption . 6
9.5.3 Decryption . 7
9.6 Data Integrity . 7
9.6.1 Protect data integrity. 7
9.6.2 Check data integrity . 7
9.7 Message Sequence Integrity . 7
10 Data Conversions . 7
10.1 Integer-to-Octet-String Conversion . 7
10.2 Octet-String-to-Integer Conversion . 7
10.3 Point-to-Octet-String Conversion . 8
10.4 Octet-String-to-Point Conversion . 8
11 SSE and SCH service invocation . 8
11.1 Pre-requisites . 9
11.2 Key Agreement . 10
11.2.1 Sender (A) Transformation . 10
11.2.2 Recipient (B) Transformation . 10
11.3 Key Derivation . 11
11.3.1 Sender (A) Transformation . 11
© ISO/IEC 2016 — All rights reserved iii

11.3.2 Recipient (B) Transformation . 11
11.4 Key Confirmation . 11
11.4.1 Sender (A) Transformation . 11
11.4.2 Recipient (B) Transformation . 12
12 SCH data exchange . 12
12.1 Preparation . 13
12.2 Data Exchange . 13
12.2.1 Send . 13
12.2.2 Receive . 13
Annex A (normative) AES-XCBC-PRF-128 and AES-XCBC-MAC-96 algorithms. 15
A.1 AES-XCBC-PRF-128. 15
A.2 AES-XCBC-MAC-96. 15
Annex B (normative) Fields sizes . 16
Annex C (informative) Informative references . 17

iv © ISO/IEC 2016 — All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on the ISO
list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT)
see the following URL: Foreword - Supplementary information
ISO/IEC 13157-2 was prepared by Ecma International (as ECMA-386) and was adopted, under a special
“fast-track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with
its approval by national bodies of ISO and IEC.
This second edition cancels and replaces the first edition (ISO/IEC 13157-2:2010) which has been technically
revised.
ISO/IEC 13157 consists of the following parts, under the general title Information technology —
Telecommunications and information exchange between systems — NFC Security:
— Part 1: NFC-SEC NFCIP-1 security services and protocol
— Part 2: NFC-SEC cryptography standard using ECDH and AES
— Part 3: NFC-SEC cryptography standard using ECDH-256 and AES-GCM
— Part 4: NFC-SEC entity authentication and key agreement using asymmetric cryptography
— Part 5: NFC-SEC entity authentication and key agreement using symmetric cryptography

To be published.
© ISO/IEC 2016 — All rights reserved v

Introduction
The NFC Security series of standards comprise a common services and protocol Standard and NFC-
SEC cryptography standards.
This NFC-SEC cryptography Standard specifies cryptographic mechanisms that use the Elliptic Curves
Diffie-Hellman (ECDH) protocol for key agreement and the AES algorithm for data encryption and
integrity.
This International Standard addresses secure communication of two NFC devices that do not share
any common secret data ("keys") before they start communicating which each other.
This edition ensures to use the latest references to cryptographic standards.

vi © ISO/IEC 2016 — All rights reserved

INTERNATIONAL STANDARD ISO/IEC 13157-2:2016(E)

Information technology — Telecommunications and information
exchange between systems — NFC Security —
Part 2:
NFC-SEC cryptography standard using ECDH and AES
1 Scope
This International Standard specifies the message contents and the cryptographic methods for PID 01.
This International Standard specifies cryptographic mechanisms that use the Elliptic Curves Diffie-Hellman
(ECDH) protocol for key agreement and the AES algorithm for data encryption and integrity.
2 Conformance
Conformant implementations employ the security mechanisms specified in this NFC-SEC cryptography
Standard (identified by PID 01) and conform to ISO/IEC 13157-1 (ECMA-385).
The NFC-SEC security services shall be established through the protocol specified in ISO/IEC 13157-1
(ECMA-385) and the mechanisms specified in this International Standard.
3 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 10116, Information technology -- Security techniques -- Modes of operation for an n-bit block cipher
ISO/IEC 11770-3, Information technology -- Security techniques -- Key management -- Part 3: Mechanisms
using asymmetric techniques
ISO/IEC 13157-1, Information technology -- Telecommunications and information exchange between systems
-- NFC Security -- Part 1: NFC-SEC NFCIP-1 security services and protocol (ECMA-385)
ISO/IEC 15946-1, Information technology -- Security techniques -- Cryptographic techniques based on elliptic
curves -- Part 1: General
ISO/IEC 18031, Information technology -- Security techniques -- Random bit generation
ISO/IEC 18033-3, Information technology -- Security techniques -- Encryption algorithms -- Part 3: Block
ciphers
ISO/IEC 18092, Information technology -- Telecommunications and information exchange between systems --
Near Field Communication -- Interface and Protocol (NFCIP-1) (ECMA-340)
IEEE 1363, IEEE Standard Specifications for Public-Key Cryptography
© ISO/IEC 2016 — All rights reserved 1

FIPS 186-4, Digital Signature Standard (DSS)
4 Terms and definitions
For the purposes of this International Standard, all terms and definitions from ISO/IEC 13157-1 (ECMA-385)
apply.
5 Conventions and notations
The conventions and notations of ISO/IEC 13157-1 (ECMA-385) as well as the following apply in this
document unless otherwise stated.
5.1 Concatenation
A || B represents the concatenation of the fields A and B: content of A followed by content of B.
5.2 Hexadecimal numbers
(XY) denotes a hexadecimal number XY (i.e. with the Radix of 16) and each pair of characters is encoded in
one octet.
6 Acronyms
For the purposes of this International Standard, all acronyms from ISO/IEC 13157-1 (ECMA-385) apply.
Additionally, the following acronyms apply.
A Sender, as specified in ISO/IEC 13157-1 (ECMA-385)
AES Advanced Encryption Standard
B Receiver, as specified in ISO/IEC 13157-1 (ECMA-385)
dA Sender’s private EC key
d Recipient’s private EC key
B
DataLen Length of the UserData
EC Elliptic Curve
ECDH Elliptic Curve Diffie-Hellman
EncData Encrypted data
G The base point on EC
ID Sender nfcid3
A
IDB Recipient nfcid3
Any Recipient identification number (e.g. ID )
ID B
R
Any Sender identification number (e.g. ID )
ID A
S
IV Initial Value
K Key
KDF Key Derivation Function
KE Encryption Key
KI Integrity Key
2 © ISO/IEC 2016 — All rights reserved

MAC Message Authentication Code
MacA /MacB Integrity protection value of Sender/ Recipient
MacTag Key confirmation tag from Sender
A
MacTagB Key confirmation tag from Recipient
MK Master Key
NA / NB Nonce generated by Sender/Recipient
NAA / NBB Nonce generated by the pair of NFC-SEC entities
NonceS Sender’s nonce
Nonce Recipient’s nonce
R
PK Public Key
PK Recipient’s Public Key
R
PKS Sender’s Public Key
PRNG Pseudo Random Number Generator
QA / QB Compressed EC public key of Sender / Recipient
Q / Q Decompressed EC public key of Sender / Recipient
A B
RNG Random Number Generator
SharedSecret Shared secret
UserData NFC-SEC User data
z Unsigned integer representation of the Shared Secret
Z Octet string representation of z
The acronyms used in Clauses 9 and 10 not listed above are formal parameters.
7 General
This International Standard specifies mechanisms for the Shared Secret Service (SSE) and the Secure
Channel Service (SCH) in ISO/IEC 13157-1 (ECMA-385).
To enable secure communication between NFC devices that do not share any common secret data ("keys")
before they start communicating with each other, public key cryptography is used to establish a shared secret
between these devices, and more specifically the Elliptic Curve Diffie-Hellman key exchange scheme. This
shared secret is used to establish the SSE and the SCH.
8 Protocol Identifier (PID)
This International Standard shall use the one octet protocol identifier PID with value 1.
9 Primitives
This Clause specifies cryptographic primitives. Clauses 11 and 12 specify the actual use of these primitives.
Table 1 summarizes the features.
© ISO/IEC 2016 — All rights reserved 3

Table 1 — Summary of features
Supported services SSE (see ISO/IEC 13157-1
(ECMA-385))
SCH (see ISO/IEC 13157-1
(ECMA-385))
Key agreement ECDH P-192
KDF AES-XCBC-PRF-128
Key confirmation AES-XCBC-MAC-96
Data encryption AES128-CTR
IV Init: AES-XCBC-PRF-128
Data integrity AES-XCBC-MAC-96
Sequence integrity SN (see ISO/IEC 13157-1
(ECMA-385))
Encryption order Encryption (9.5) before MAC
calculation (9.6)
9.1 Key agreement
Peer NFC-SEC entities shall agree on a shared secret using Key agreement mechanism 4
...