ISO/IEC INTERNATIONAL STANDARD 10116 Fourth edition 2017-07 Information technology Security techniques Modes of operation for an n-bit block cipher Technologies de I'information - Techniques de sécurité - Modes opératoires pour un chiffrement par blocs de n bits Reference number IEC IS0/IEC 10116:2017(E) rso International Organization for Standardization STANDARDIZATIONC15956617 @IS0/IEC2017 ed without license from IHS IS0/IEC 10116:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0/IEC 2017, 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. ISOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Intenationaibr PrganizationforStandardization icensee-ZHEJIANG INST.OF STANJSA6FC31.7 -All rights reserved Not for Resale, 2017/9/11 05:15:00 etworking permitted without license from IHS IS0/IEC 10116:2017(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. ..1 2 Normative references ...1. 3 Terms and definitions 4 Symbols, abbreviated terms and notation ..3 4.1 Symbols and abbreviated terms .3 4.2 Notation. .4 5 Requirements ..4 6 Electronic Codebook (ECB) mode .5 6.1 Preliminaries .5 6.2 Encryption. .5 6.3 Decryption .5 7 Cipher Block Chaining (CBC) mode. .6 7.1 Preliminaries .6 7.2 Encryption. .6 7.3 Decryption .6 7.4 Avoiding ciphertext expansion. .7 7.4.1 General. .7 7.4.2 Three ciphertext stealing variants of CBC .7 8 Cipher Feedback (CFB) mode ..8 8.1 Preliminaries ..8 8.2 Encryption .9 8.3 Decryption .10 8.4 Avoiding ciphertext expansion .10 9 Output Feedback (OFB) mode .11 9.1 Preliminaries .11 9.2 Encryption .11 9.3 Decryption .12 9.4 Avoiding ciphertext expansion .12 10 Counter (CTR) mode .13 10.1 Preliminaries .13 10.2 Encryption. .13 10.3 Decryption .14 10.4 Avoiding ciphertext expansion. .14 Annex A (normative) Object identifiers .15 Annex B (informative) Properties of the modes of operation and important security guidance....17 Annex C (informative) Figures describing the modes of operation .22 Annex D (informative) Numerical examples for the modes of operation ..27 Bibliography .39 iii See=ZHEJIANG INSTOFSTANDARDIZATIONC15956617 ed without license from IHS Not for Resale, 2017/9/11 05:15:00