INTERNATIONAL ISO/IEC STANDARD 9797-2 Third edition 2021-06 Informationsecurity-Message authenticationcodes(MACs)- Part 2: Mechanisms using a dedicated hash- function Securite de I'information-Codes d'authentication demessage (MAC) - Partie 2:Mecanismesutilisantune fonction de hachagedediee Reference number ISO/IEC9797-2:2021(E) IEC TSO @IS0/IEC2021 Copyright Intemafional Organization tor Standardizatior IS0/IEC9797-2:2021(E) COPYRIGHTPROTECTEDDOCUMENT IS0/IEC2021 All rightsreserved,Unless otherwise specified,orrequired in the contextofits implementation,no partof this publication may be reproduced or utilizedotherwise in anyform orby anymeans,electronic ormechanical,including photocopying,orposting on the internet or an intranet, without prior written permission. Permission can be requested from either Iso at the address beloworISO'smemberbodyinthecountryoftherequester. ISO copyrightoffice CP401.Ch.deBlandonnet8 CH-1214 Vernier, Geneva Phone:+41227490111 Email:[email protected] Website:www.iso.org PublishedinSwitzerland Ca @IS0/IEC2021-Allrightsreserved IS0/IEC9797-2:2021(E) Contents Page Foreword .V 1 Scope, .1 2 Normativereferences .1 3 Termsand definitions .1 4 Symbolsand notation .3 5 Requirements. .5 6 MACAlgorithm1 6 6.1 General. 6 6.2 Description of MACAlgorithm1 .7 6.2.1 General. 7 6.2.2 Step1 (keyexpansion) 7 6.2.3 Step 2 (modification of the constants and theIV) 1 6.2.4 Step3 (hashingoperation) 8 6.2.5 Step4 (outputtransformation) 8 6.2.6 Step5 (truncation) 8 6.3 .8 Efficiency 6.4 Computationof theconstants. 8 8 6.4.1 General. 6.4.2 Dedicated hash-function1(RIPEMD-160) 9 6.4.3 Dedicated hash-function2 (RIPEMD-128) 9 6.4.4 Dedicated hash-function3 (SHA-1) 10 6.4.5 Dedicatedhash-function4(SHA-256) 10 6.4.6 Dedicated hash-function 5 (SHA-512) 10 6.4.7 Dedicatedhash-function6(SHA-384) 11 6.4.8 Dedicatedhash-function8 (SHA-224) 11 6.4.9 12 Dedicatedhash-function17(SM3) MACAlgorithm 2 .12 7 7.1 12 General 7.2 DescriptionofMACAlgorithm2 .12 7.2.1 General. 12 7.2.2 .13 Step1(keyexpansion) 7.2.3 .13 Step2 (hashingoperation) 7.2.4 Step3 (outputtransformation) 13 7.2.5 Step 4 (truncation). 13 Efficiency 7.3 13 MAC Algorithm 3. .13 8 8.1 General. 13 8.2 DescriptionofMACAlgorithm3 14 8.2.1 .14 General. 8.2.2 Step1 (keyexpansion) 14 8.2.3 Step2 (modification of the constants and theIV) 14 8.2.4 Step3(padding) 15 8.2.5 .15 Step4 (applicationoftheround-function) 8.2.6 Step 5 (truncation) 15 8.3 Efficiency 15 .15 MAC Algorithm 4 6 9.1 15 General. 9.2 DescriptionofMACAlgorithm 4 16 9.3 Encoding and padding. .16 9.3.1 Integerto byte encoding .16 9.3.2 String encoding 17 iii CoprgtrmaooAllighrseed