APPENDIX- A REFERENCE IMPLEMENTATION OF BSF-128 ===============================================================

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1 APPENDICES

2 A p p e n d i c e s P a g e 144

3 A p p e n d i c e s P a g e 145 APPENDIX- A REFERENCE IMPLEMENTATION OF BSF-128 =============================================================== REFERENCE IMPLEMENTATION OF STREAM CIPHER BSF-128 Filename: BSF128.c Author: Shadab Alam Dept. of Computer Science AMU, Aligarh India, s4shadab@gmail.com Synopsis: This file contains functions that implement the stream cipher BSF-128. It also implements functions specified by the ECRYPT API. / #include<stdio.h> #include "ecryptportable.h" #include "ecryptmachine.h" #include "ecryptconfig.h" #include "ecryptsync.h" #include "sbox.h" #include "multab.h" #define WORD unsigned short typedef enum false=0, true=1 bool; void ECRYPT_init(void) Function: bsf_keystream Synopsis Generates a new bit and updates the internal state of the cipher. / int mb = 1; u16 bsf_keystream(ecrypt_ctx ctx)

4 A p p e n d i c e s P a g e 146 u8 i,outbit1[8],outp; bool NBit,LBit; u16 outbit,ks; outbit1[0] = ctx->nfsr[31]; outbit1[1] = ctx->nfsr[59]; outbit1[2] = ctx->nfsr[75]; outbit1[3] = ctx->fcsr[21]; outbit1[4] = ctx->fcsr[39]; outbit1[5] = ctx->fcsr[51]; outbit1[6] = ctx->fcsr[73]; outbit1[7] = ctx->fcsr[120]; outp=0; for(i=0;i<8;i++) outp = outp outbit1[i];//outbit1[0]^outbit1[1]^outbit1[2]^outbit1[3]^outbit1[ 4]^outbit1[5]^outbit1[6]^outbit1[7] outp = outp<<1; Calculate feedback and output bits / //printf("outp=%x",outp); ks = SBox[outp]; outbit = (ks & 0xFF00) (((ks & 0x00FF)^outp) & 0x00FF); NBit=ctx->FCSR[0]^ctx->NFSR[0]^ctx->NFSR[26]^ctx- >NFSR[56]^ctx->NFSR[91]^ctx->NFSR[96]^(ctx->NFSR[3]&ctx- >NFSR[67])^(ctx->NFSR[11]&ctx->NFSR[13])^(ctx->NFSR[17]&ctx- >NFSR[18])^(ctx->NFSR[27]&ctx->NFSR[59])^(ctx->NFSR[40]&ctx- >NFSR[48])^(ctx->NFSR[61]&ctx->NFSR[65])^(ctx->NFSR[68]&ctx- >NFSR[84]); //NBit%=2; u8 sig = ctx->fcsr[0] + ctx->fcsr[99]+ ctx->fcsr[101]+ctx- >FCSR[126]+mb; LBit=sig%2; mb = (sig/2); //printf("nfsr:%x\tfcsr:%x\n",nbit,lbit); ctx->fcsr[0]^ctx->fcsr[7]^ctx->fcsr[38]^ctx->fcsr[70]^ctx- >FCSR[81]^ctx->FCSR[96]; / Update registers / for (i=1;i<(ctx->keysize);++i) ctx->nfsr[i-1]=ctx->nfsr[i]; ctx->fcsr[i-1]=ctx->fcsr[i]; ctx->nfsr[(ctx->keysize)-1]=nbit; ctx->fcsr[(ctx->keysize)-1]=lbit; return outbit; //Key Initialization void bsf_key_initialization(ecrypt_ctx ctx) u8 i,outbit1[8],outp;

5 A p p e n d i c e s P a g e 147 bool NBit,LBit,FBit; u16 outbit,ks; outbit1[0] = ctx->nfsr[31]; outbit1[1] = ctx->nfsr[59]; outbit1[2] = ctx->nfsr[75]; outbit1[3] = ctx->fcsr[21]; outbit1[4] = ctx->fcsr[39]; outbit1[5] = ctx->fcsr[51]; outbit1[6] = ctx->fcsr[73]; outbit1[7] = ctx->fcsr[120]; outp=0; for(i=0;i<8;i++) outp = outp outbit1[i];//outbit1[0]^outbit1[1]^outbit1[2]^outbit1[3]^outbit1[ 4]^outbit1[5]^outbit1[6]^outbit1[7] outp = outp<<1; Calculate feedback and output bits / //printf("outp=%x",outp); ks = SBox[outp]; outbit = (ks & 0xFF00) (((ks & 0x00FF)^outp) & 0x00FF); NBit=ctx->FCSR[0]^ctx->NFSR[0]^ctx->NFSR[26]^ctx- >NFSR[56]^ctx->NFSR[91]^ctx->NFSR[96]^(ctx->NFSR[3]&ctx- >NFSR[67])^(ctx->NFSR[11]&ctx->NFSR[13])^(ctx->NFSR[17]&ctx- >NFSR[18])^(ctx->NFSR[27]&ctx->NFSR[59])^(ctx->NFSR[40]&ctx- >NFSR[48])^(ctx->NFSR[61]&ctx->NFSR[65])^(ctx->NFSR[68]&ctx- >NFSR[84]); //NBit%=2; u8 sig = ctx->fcsr[0] + ctx->fcsr[99]+ ctx->fcsr[101]+ctx- >FCSR[126]+mb; FBit = ctx->fcsr[0]; LBit=sig%2; mb = (sig/2); //printf("nfsr:%x\tfcsr:%x\n",nbit,lbit); ctx->fcsr[0]^ctx->fcsr[7]^ctx->fcsr[38]^ctx->fcsr[70]^ctx- >FCSR[81]^ctx->FCSR[96]; / Update registers / for (i=1;i<(ctx->keysize);++i) ctx->nfsr[i-1]=ctx->nfsr[i]; ctx->fcsr[i-1]=ctx->fcsr[i]; ctx->nfsr[(ctx->keysize)-1]=nbit ^ (outbit & 0x1000); ctx->fcsr[(ctx->keysize)-1]=lbit ^ (outbit & 0x0001); //return outbit; Functions for the ECRYPT API / int powerr(int val,int times)

6 A p p e n d i c e s P a g e 148 int n = 1,i; for(i=0;i<times;i++) n=nval; return n; void ECRYPT_keysetup( ECRYPT_ctx ctx, const u8 key, u32 keysize, Key size in bits. / u32 ivsize) IV size in bits. / ctx->p_key=key; ctx->keysize=keysize; ctx->ivsize=ivsize; Function: ECRYPT_ivsetup Synopsis Load the key and perform initial clockings. Assumptions The key is 16 bytes and the IV is 16 bytes. The registers are loaded in the following way: NFSR[0] = lsb of key[0]... NFSR[7] = msb of key[0] NFSR[120] = lsb of key[16]... NFSR[127] = msb of key[16] FCSR[0] = lsb of IV[0]... FCSR[7] = msb of IV[0] FCSR[120] = lsb of key[16]... FCSR[127] = msb of key[16] / void ECRYPT_ivsetup( ECRYPT_ctx ctx, const u8 iv) u32 i,j; u16 outbit; load registers /

7 A p p e n d i c e s P a g e 149 //ctx->fcsr = iv; for (i=0;i<(ctx->keysize)/8 && i<16;++i) for (j=0;j<8;++j) ctx->nfsr[i8+j] = (ctx->p_key[i]>>j)&1; ctx->fcsr[i8+j]=((iv[i]>>j)&1); for (i=(ctx->keysize)/8;i<16;++i) for (j=0;j<8;++j) ctx->nfsr[i8+j]=((ctx->p_key[i]<<j)&1); ctx->fcsr[i8+j]=1; / do initial clockings / for (i=0;i<256;++i) bsf_key_initialization(ctx); int outputl = (u16)outbit & 0x0001; int outputm = (u16)outbit & 0x1000; //printf("\noutbit=%x\toutputl=%x\toutputm=%x",outbit,outputl,out putm); ctx->fcsr[127]^=outputl; ctx->nfsr[127]^=outputm; / Function: ECRYPT_keystream_bytes Synopsis Generate keystream in bytes. / void ECRYPT_keystream_bytes( ECRYPT_ctx ctx, u8 keystream, u32 msglen) u32 i,j; for (i = 0; i < msglen; ++i) for (j = 0; j < 8; ++j) keystream[i]=(bsf_keystream(ctx)); void ECRYPT_encrypt_bytes( ECRYPT_ctx ctx, const u8 plaintext,

8 A p p e n d i c e s P a g e 150 u8 ciphertext, u32 msglen) u32 i,j; u8 k=0; for (i=0;i<msglen;++i) k=0; for (j=0;j<8;++j) k =(bsf_keystream(ctx)<<j); ciphertext[i]=plaintext[i]^k; void ECRYPT_decrypt_bytes( ECRYPT_ctx ctx, const u8 ciphertext, u8 plaintext, u32 msglen) u32 i,j; u8 k=0; for (i=0;i<msglen;++i) k=0; for (j = 0; j < 8; ++j) k =(bsf_keystream(ctx)<<j); plaintext[i]=ciphertext[i]^k; int find_length(char input) //printf("%s", input); int length = 0; while(input[length]!='\0'); length++; // printf("%i", length); return length; void main() ECRYPT_ctx ctx; u8 plaintext; u8 ciphertext; u8 keystream; u32 msglen; u8 key;

9 A p p e n d i c e s P a g e 151 printf("enter Plain Text:"); scanf("%d",&plaintext); printf("key Stream:128 bit\n"); scanf("%d",&key); //int len = find_length(plaintext); printf("ffffff"); ECRYPT_keystream_bytes(&ctx," ",128); ECRYPT_keysetup(&ctx,"kkkkkkkkk",128,128); ECRYPT_encrypt_bytes(&ctx,"kkkkkkkkk",&ciphertext,128); printf("cipher=%d",ciphertext); /

10 A p p e n d i c e s P a g e 152 APPENDIX- B S-BOX USED IN BSF-128 =============================================================== #define WORD unsigned short WORD SBox[256] = 0xa3db, 0xd76e, 0x0966, 0x83d0, 0xf8be, 0x4858, 0xf611, 0xf4cf, 0xb314, 0x212d, 0x15a2, 0x78dd, 0x99f5, 0xb1c4, 0xafed, 0xf981, 0xe79b, 0x2daa, 0x4d40, 0x8a75, 0xce54, 0x4cd5, 0xcad5, 0x2e75, 0x522d, 0x951a, 0xd91a, 0x1e73, 0x4e4a, 0x387c, 0x442c, 0x28b3, 0x0a21, 0xdfb6, 0x02d4, 0xa03e, 0x1734, 0xf158, 0x6074, 0x682c, 0x1271, 0xb7f5, 0x7a76, 0xc391, 0xe9df, 0xfab5, 0x3d04, 0x532e, 0x96e2, 0x843b, 0x6b22, 0xba34, 0xf2a7, 0x63c8, 0x9afb, 0x1932, 0x7c2e, 0xaee5, 0xe540, 0xf5ad, 0xf727, 0x163e, 0x6a9a, 0xa2ee, 0x3919, 0xb68e, 0x7be1, 0x0ff9, 0xc1e9, 0x9348, 0x816a, 0x1bd0, 0xee85, 0xb4c9, 0x1a63, 0xea16, 0xd013, 0x9186, 0x2f7b, 0xb828, 0x559d, 0xb917, 0xdabc, 0x8541, 0x3f12, 0x4140, 0xbfc1, 0xe0cb, 0x5a4e, 0x588d, 0x80eb, 0x5f96, 0x663f, 0x0b58, 0xd882, 0x902f, 0x35dd, 0xd522, 0xc045, 0xa7a2, 0x33bc, 0x068a, 0x65a0, 0x6965, 0x4515, 0x00b6, 0x9422, 0x5615, 0x6dcb, 0x985f, 0x9b67, 0x762c, 0x9795, 0xfc94, 0xb20c, 0xc2bd, 0xb0f8, 0xfeeb, 0xdb44, 0x20f6, 0xe1a9, 0xeb0b, 0xd6e3, 0xe4c0, 0xdd18, 0x47b7, 0x4a03, 0x1d16, 0x42db, 0xed8f, 0x9e11, 0x6e60, 0x4950, 0x3cd9, 0xcdfa, 0x43ae, 0x27d8, 0xd28c, 0x0765, 0xd451, 0xdedb, 0xc780, 0x67d8, 0x1868,

11 A p p e n d i c e s P a g e 153 0x890f, 0xcbf7, 0x303d, 0x1f5a, 0x8daa, 0xc6d9, 0x8fad, 0xaac4, 0xc862, 0x74a3, 0xdc5a, 0xc94d, 0x5d1b, 0x5cf1, 0x3169, 0xa45c, 0x7098, 0x88a8, 0x61a0, 0x2c66, 0x9f03, 0x0d5d, 0x2b3c, 0x8736, 0x502f, 0x82a0, 0x540b, 0x648a, 0x267e, 0x7db9, 0x0345, 0x400d, 0x345e, 0x4bce, 0x1cd6, 0x73fe, 0xd1b0, 0xc485, 0xfd5e, 0x3bfc, 0xccd6, 0xfbd3, 0x7f06, 0xab01, 0xe668, 0x3ee8, 0x5ba5, 0xa56e, 0xadce, 0x041d, 0x2313, 0x9c5f, 0x14c6, 0x51f0, 0x22e0, 0xf0f3, 0x29d5, 0x7933, 0x7182, 0x7eef, 0xff9b, 0x8c65, 0x0e23, 0xe2c1, 0x0c3d, 0xef61, 0xbcf8, 0x7296, 0x7581, 0x6f90, 0x37ff, 0xa145, 0xec47, 0xd363, 0x8e13, 0x62bf, 0x8b2e, 0x8628, 0x103b, 0xe83c, 0x08ce, 0x7782, 0x11f7, 0xbec0, 0x92ef, 0x4f2c, 0x244b, 0xc593, 0x326b, 0x36bd, 0x9dd0, 0xcfd7, 0xf380, 0xa6f6, 0xbb4e, 0xac75, 0x5e68, 0x6cf3, 0xa933, 0x1347, 0x570b, 0x2503, 0xb597, 0xe33c, 0xbdef, 0xa872, 0x3a38, 0x01aa, 0x053f, 0x5991, 0x2a0e, 0x4698, ;

Keywords: CRC, CRC-7, cyclic redundancy check, industrial output, PLC, programmable logic controller, C code, CRC generation, microprocessor, switch

Keywords: CRC, CRC-7, cyclic redundancy check, industrial output, PLC, programmable logic controller, C code, CRC generation, microprocessor, switch APPLICATION NOTE 6002 CRC PROGRAMMING FOR THE MAX14900E