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Input .KÖÝLWDÑRKRDÛQYÔ L 1 =Ro Ro + F + F + F ³DÝRNKÖÝLWDÑRKRÛDQYÔ 2XWSXW Lo R 1 = Lo + F(R 1 ,K 1 ) L 15 = R 14 R 2 = L 1 + F(R 1 ,K 2 )L 2 = R 1 R 15 = L 14 + F(R 14 ,K 15 ) + F R 16 = L 15 + F(R 15 ,K 16 ) L 16 = R 15 1,2,3, 64 1,2,3, 64 1,2,3, 32 K 1 K 2 Kn K 16 Hình 1: Encr y ption computation 1,2,3, 32 &KRÑQKRÛDQYÔ /HIW6KLIW /HIW6KLIW /HIW6KLIW/HIW6KLIW /HIW6KLIW /HIW6KLIW &KRÑQKRÛDQYÔ &KRÑQKRDÛQYÔ &KRÑQKRDÛQYÔ 1,2,3, 64 1,2,3, 28 1,2,3, 28 K 1 Kn K 16 +ÎQK Key Schedule Calculation Key Key Key C 1 D 1 Cn Dn C 16 D 16 S 1 S 2 S 3 S 6 S 5 S 7 S 4 S 8 P 32 bits + E 48 bits K ( 48 bits ) 5 ELWV Hình 3 : Calculation of f(R,K) 6 4 %DÝQJD%DÝQJKRDÛQYÔÓDÂXWLHÄQ,3  %DÝQJE%DÝQJKRDÛQYÔFXRÃLFXÚQJ,3  %DÝQJ%DÝQJFKRÑQEÏW( %DÝQJ%DÝQJKRDÛQYÔ3 %DÝQJ%DÝQJKRDÛQYÔNKRÛD3& %DÝQJ%DÝQJKRDÛQYÔNKRÛD3&                                                                        &ROXPQ 5RZ%R[ 6 6 6 6 6 6 6 6 %DÝQJ%DÝQJFKRÑQ6ER[H[ '(6,Q(OHFWURQLF&RGH%RRN0RGH(&% ảẵPRGHQD\FDFNKRLGDWDGỉệLGDẹQJURíFOHDUWH[WểỉệẹFểỉDYDRLQSXWFXíD'(6 &DFNKRLNHWTXDíGỉệLGDẹQJPDặWPDìFLSKHUWH[WFRWKHầểỉệẹFVỉíGXẹQJFKRFDFỉQJGXẹQJ NKDF4XDWUẻQKELHQểRầLGLHQUDQKỉVDXKẻQK &OHDUWH[Wặ,QSXWEORFNặ'(6ặ2XWSXWEORFNặ&LSKHUWH[W (&%HQFU\SWLRQ (&%GHFULSWLRQ +ẻQK(OHFWURQLF&RGHERRN0RGH(&% '(6,Q&LSKHU%ORFN&KDLQLQJ0RGH&%& .KRLGDWDFDQPDìKRDểỉệẹFFKLDWKDQKFDFNKRL% % g% YệLNẽFKWKỉệFPRL NKRLODELWV9HFWệNKệíLWDẹR,9ELWVểỉệẹFFKRẹQ6ệểRPDặWPDìểỉRẹFFKRWURQJKẻQK 4XDWUẻQKPDìKRD ,9% & &OHDUWH[W ' ' ' ,QSXWEORFN , , g, '(6HQFU\SW 2XWSXWEORFN 2 2 g2 &LSKHUWH[W & & g& &OHDUWH[W ' ' ' &LSKHUWH[W & & g& ,QSXWEORFN , , g, '(6GHFU\SW 2XWSXWEORFN 2 2 g2 & ⊕% &   Q& ⊕% &  4XDÛWUÎQKJLDÝLPD× &  ,9⊕% ,9⊕% ⊕,9 % &  & ⊕% & ⊕% ⊕&  %   & &⊕% & ⊕% ⊕&  % +ÎQK&LSKHU%ORFN&KDLQLQJ&%&PRGH ,9 % % % Time = 1 Time = 2 Time = n + + + ,,, '(6HQFU\ '(6HQFU\ '(6HQFU\ & & & , , , '(6GHFU\ '(6GHFU\ '(6GHFU\ ,9 + + + %% % 0D×KRÛD *LDÝLPD×