祖冲之算法：ZUC-256算法草案(英文)

The ZUC-256 Stream CipherAbstract.In this paper,we describe the ZUC-256 stream cipher,asuccessor of the previous ZUC-128 stream cipher used in the 3GPP con-fidentiality and integrity algorithms 128-EEA3 and 128-EIA3.The aim isa new stream cipher that offers the 256-bit security for the upcoming ap-plications in 5G.For the authentication,various tag sizes are supportedwith the IV-respecting restriction.Keywords:Stream ciphers,ZUC,256-bit security.1 IntroductionThe core of the 3GPP confidentiality and integrity algorithms 128-EEA3 and128-EIA3 is the ZUC-128 stream cipher [1].With the development of the com-munication and computing technology,there is an emerging need for the newcore stream cipher in the upcoming 5G applications which offers 256-bit security.To be highly compatible with the current 128-bit version,we present the ZUC.256 stream cipher,which is a successor of the previous ZUC-128 stream cipherThe new ZUC-256 stream cipher differs from ZUC-128 only in the initializationphase and in the message authentication codes (MAC)generation phase,otheraspects are all the same as the previous ZUC-128 algorithm.This paper is structured as follows.In Section 2,we give the detailed descrip-tion of the new ZUC-256 stream cipher,including both the initialization phase,the keystream generation phase and the MAC generation phase.Finally,someconclusions are drawn in Section 3.2 The Description of the CipherIn this section,we will present the detailed description of the ZUC-256 streamcipher.The following notations will be used hereafter.-Denote the integer modular addition by田，i.e,for0≤x<22and0≤y<232,xy is the integer addition mod 232.Denote the integer addition modulo 231-1 by r+y mod 231-1 for 1x≤231-1and1≤y≤231-1.Denote the bitwise exclusive OR byDenote the bit string concatenation by.Denote the bitwise logic OR by-K=(K31,K3o,..K2,K1,Ko),the 256-bit secret key used in the ZUC-256where K:for0≤i≤31are&bit bytes..