INTERNATIONAL ISO/IEC STANDARD 27551 First edition 2021-09 Information security, cybersecurity and privacy protection : Requirements for attribute-based unlinkable entity authentication Sécurité de I'information, cybersécurité et protection de la vie privée -Exigences relatives a I'authentification des entites non rattachables par des attributs Reference number IEC IS0/IEC 27551:2021(E) iso @IS0/IEC2021 IS0/IEC 27551:2021(E) COPYRIGHT PROTECTED DOCUMENT @IS0/IEC2021 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 CP 40i : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone:+4122 749 0111 Email: copyright@iso.org Website:www.iso.org Published in Switzerland ii @ IS0/IEC 2021 - All rights reserved