X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=bmw%2Fbmw_large.c;h=1bae63f2794f917d544a6287e18bc11ecff31c11;hb=d9352fc79fbdee0cf3288809b104ea196ea85693;hp=10e65f6dabad5abb6c77153fee05a844d737aa9f;hpb=d32eba56ce10ea6b9eff123b50d9842673b38f2b;p=avr-crypto-lib.git diff --git a/bmw/bmw_large.c b/bmw/bmw_large.c index 10e65f6..1bae63f 100644 --- a/bmw/bmw_large.c +++ b/bmw/bmw_large.c @@ -1,7 +1,7 @@ /* bmw_large.c */ /* This file is part of the AVR-Crypto-Lib. - Copyright (C) 2009 Daniel Otte (daniel.otte@rub.de) + Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -19,10 +19,10 @@ /* * \file bmw_large.c * \author Daniel Otte - * \email daniel.otte@rub.de + * \email bg@nerilex.org * \date 2009-04-27 * \license GPLv3 or later - * + * */ #include @@ -30,18 +30,20 @@ #include #include "bmw_large.h" -#define SHL64(a,n) ((a)<<(n)) -#define SHR64(a,n) ((a)>>(n)) -#define ROTL64(a,n) (((a)<<(n))|((a)>>(64-(n)))) -#define ROTR64(a,n) (((a)>>(n))|((a)<<(64-(n)))) +#define SHL64(a,n) shiftl64(a,n) +#define SHR64(a,n) shiftr64(a,n) +#define ROTL64(a,n) rotl64(a,n) +#define ROTR64(a,n) rotr64(a,n) + +#define TWEAK 1 +#define BUG24 0 +#define F0_HACK 2 +#define DEBUG 0 -#define BUG24 0 -#define F0_HACK 1 -#define DEBUG 0 #if DEBUG #include "cli.h" - - void ctx_dump(const bmw_large_ctx_t* ctx){ + + void ctx_dump(const bmw_large_ctx_t *ctx){ uint8_t i; cli_putstr_P(PSTR("\r\n==== ctx dump ====")); for(i=0; i<16;++i){ @@ -53,8 +55,8 @@ cli_putstr_P(PSTR("\r\n counter = ")); cli_hexdump(&(ctx->counter), 4); } - - void dump_x(const uint64_t* q, uint8_t elements, char x){ + + void dump_x(const uint64_t *q, uint8_t elements, char x){ uint8_t i; cli_putstr_P(PSTR("\r\n==== ")); cli_putc(x); @@ -73,110 +75,143 @@ #define dump_x(a,b,c) #endif +static +uint64_t rotl64(uint64_t a, uint8_t r){ + return (a<>(64-r)); +} + +static +uint64_t rotr64(uint64_t a, uint8_t r){ + return (a>>r)|(a<<(64-r)); +} + +static +uint64_t shiftl64(uint64_t a, uint8_t r){ + return (a<>r); +} + +static uint64_t bmw_large_s0(uint64_t x){ uint64_t r; r = SHR64(x, 1) ^ SHL64(x, 3) ^ ROTL64(x, 4) ^ ROTR64(x, 64-37); - return r; + return r; } +static uint64_t bmw_large_s1(uint64_t x){ uint64_t r; r = SHR64(x, 1) ^ SHL64(x, 2) ^ ROTL64(x,13) ^ ROTR64(x,64-43); - return r; + return r; } +static uint64_t bmw_large_s2(uint64_t x){ uint64_t r; r = SHR64(x, 2) ^ SHL64(x, 1) ^ ROTL64(x, 19) ^ ROTR64(x, 64-53); - return r; + return r; } +static uint64_t bmw_large_s3(uint64_t x){ uint64_t r; r = SHR64(x, 2) ^ SHL64(x, 2) ^ ROTL64(x, 28) ^ ROTR64(x, 64-59); - return r; + return r; } +static uint64_t bmw_large_s4(uint64_t x){ uint64_t r; r = SHR64(x, 1) ^ x; - return r; + return r; } +static uint64_t bmw_large_s5(uint64_t x){ uint64_t r; r = SHR64(x, 2) ^ x; - return r; + return r; } +static uint64_t bmw_large_r1(uint64_t x){ uint64_t r; r = ROTL64(x, 5); - return r; + return r; } +static uint64_t bmw_large_r2(uint64_t x){ uint64_t r; r = ROTL64(x, 11); - return r; + return r; } +static uint64_t bmw_large_r3(uint64_t x){ uint64_t r; r = ROTL64(x, 27); - return r; + return r; } +static uint64_t bmw_large_r4(uint64_t x){ uint64_t r; r = ROTL64(x, 32); - return r; + return r; } +static uint64_t bmw_large_r5(uint64_t x){ uint64_t r; r = ROTR64(x, 64-37); - return r; + return r; } +static uint64_t bmw_large_r6(uint64_t x){ uint64_t r; r = ROTR64(x, 64-43); - return r; + return r; } +static uint64_t bmw_large_r7(uint64_t x){ uint64_t r; r = ROTR64(x, 64-53); - return r; + return r; } /* #define K 0x0555555555555555LL #define MASK 0xFFFFFFFFFFFFFFFFLL static -uint64_t k_lut[] PROGMEM = { - 16LL*K, 17LL*K, 18LL*K, 19LL*K, +const uint64_t k_lut[] PROGMEM = { + 16LL*K, 17LL*K, 18LL*K, 19LL*K, 20LL*K, 21LL*K, 22LL*K, 23LL*K, 24LL*K, 25LL*K, 26LL*K, 27LL*K, 28LL*K, 29LL*K, 30LL*K, 31LL*K }; -*/ +*/ /* the same as above but precomputed to avoid compiler warnings */ static -uint64_t k_lut[] PROGMEM = { +const uint64_t k_lut[] PROGMEM = { 0x5555555555555550LL, 0x5aaaaaaaaaaaaaa5LL, 0x5ffffffffffffffaLL, 0x655555555555554fLL, 0x6aaaaaaaaaaaaaa4LL, 0x6ffffffffffffff9LL, 0x755555555555554eLL, 0x7aaaaaaaaaaaaaa3LL, 0x7ffffffffffffff8LL, @@ -184,8 +219,10 @@ uint64_t k_lut[] PROGMEM = { 0x955555555555554cLL, 0x9aaaaaaaaaaaaaa1LL, 0x9ffffffffffffff6LL, 0xa55555555555554bLL }; -uint64_t bmw_large_expand1(uint8_t j, const uint64_t* q, const void* m){ +static +uint64_t bmw_large_expand1(uint8_t j, const uint64_t *q, const void *m, const void *h){ uint64_t(*s[])(uint64_t) = {bmw_large_s1, bmw_large_s2, bmw_large_s3, bmw_large_s0}; + uint64_t a = 0; union{ uint64_t v64; uint32_t v32[2]; @@ -195,18 +232,29 @@ uint64_t bmw_large_expand1(uint8_t j, const uint64_t* q, const void* m){ r.v32[0] = pgm_read_dword(((uint8_t*)k_lut+8*j)); r.v32[1] = pgm_read_dword(((uint8_t*)k_lut+8*j+4)); for(i=0; i<16; ++i){ - r.v64 += s[i%4](q[j+i]); + a += s[i%4](q[j+i]); } - r.v64 += ((uint64_t*)m)[j]; - r.v64 += ((uint64_t*)m)[j+3]; - r.v64 -= ((uint64_t*)m)[j+10]; - return r.v64; +#if TWEAK + a += ( ROTL64(((uint64_t*)m)[(j)&0xf], ((j+ 0)&0xf)+1) + + ROTL64(((uint64_t*)m)[(j+3)&0xf], ((j+ 3)&0xf)+1) + + r.v64 + - ROTL64(((uint64_t*)m)[(j+10)&0xf],((j+10)&0xf)+1) + ) ^ ((uint64_t*)h)[(j+7)&0xf]; +#else + a += ((uint64_t*)m)[j&0xf]; + a += ((uint64_t*)m)[(j+3)&0xf]; + a -= ((uint64_t*)m)[(j+10)&0xf]; + a += r.v64; +#endif + return a; } -uint64_t bmw_large_expand2(uint8_t j, const uint64_t* q, const void* m){ +static +uint64_t bmw_large_expand2(uint8_t j, const uint64_t *q, const void *m, const void *h){ uint64_t(*rf[])(uint64_t) = {bmw_large_r1, bmw_large_r2, bmw_large_r3, bmw_large_r4, bmw_large_r5, bmw_large_r6, bmw_large_r7}; + uint64_t a=0; union{ uint64_t v64; uint32_t v32[2]; @@ -216,29 +264,105 @@ uint64_t bmw_large_expand2(uint8_t j, const uint64_t* q, const void* m){ r.v32[0] = pgm_read_dword(((uint8_t*)k_lut+8*j)); r.v32[1] = pgm_read_dword(((uint8_t*)k_lut+8*j+4)); for(i=0; i<14; i+=2){ - r.v64 += q[j+i]; + a += q[j+i]; } for(i=0; i<14; i+=2){ - r.v64 += rf[i/2](q[j+i+1]); + a += rf[i/2](q[j+i+1]); + } +#if TWEAK + a += bmw_large_s4(q[j+14]); + a += bmw_large_s5(q[j+15]); +#else + a += bmw_large_s5(q[j+14]); + a += bmw_large_s4(q[j+15]); +#endif +#if TWEAK + /* + if(j==(22-16)){ + uint64_t t; + cli_putstr_P(PSTR("\n+++++++++ expand_2 ++++++++++++")); + dump_x(&a, 1, 'a'); + dump_x(&r, 1, 'r'); + t=ROTL64(((uint64_t*)m)[j], ((j+ 0)&0xf)+1); + dump_x(&t, 1, '0'); + t=ROTL64(((uint64_t*)m)[j], ((j+ 3)&0xf)+1); + dump_x(&t, 1, '0'); + t=ROTL64(((uint64_t*)m)[j], ((j+ 0)&0xf)+1); + dump_x(&t, 1, '0'); + + } + */ + a += ( ROTL64(((uint64_t*)m)[(j)&0xf], ((j+ 0)&0xf)+1) + + ROTL64(((uint64_t*)m)[(j+3)&0xf], ((j+ 3)&0xf)+1) + + r.v64 + - ROTL64(((uint64_t*)m)[(j+10)&0xf],((j+10)&0xf)+1) + ) ^ ((uint64_t*)h)[(j+7)&0xf]; +#else + a += ((uint64_t*)m)[j&0xf]; + a += ((uint64_t*)m)[(j+3)&0xf]; + a -= ((uint64_t*)m)[(j+10)&0xf]; + a += r.v64; +#endif + return a; +} + +#if F0_HACK==2 +/* to understand this implementation take a look at f0-opt-table.txt */ +static const uint16_t hack_table[5] PROGMEM = { 0x0311, 0xDDB3, 0x2A79, 0x07AA, 0x51C2 }; +static const uint8_t offset_table[5] PROGMEM = { 4+16, 6+16, 9+16, 12+16, 13+16 }; + + +static +void bmw_large_f0(uint64_t *q, const uint64_t *h, const void *m){ + uint16_t hack_reg; + uint8_t i,j,c; + uint64_t(*s[])(uint64_t)={ bmw_large_s0, bmw_large_s1, bmw_large_s2, + bmw_large_s3, bmw_large_s4 }; + for(i=0; i<16; ++i){ + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; + } + dump_x(h, 16, 'T'); + memset(q, 0, 8*16); + c=4; + do{ + i=15; + j=pgm_read_byte(offset_table+c); + hack_reg=pgm_read_word(&(hack_table[c])); + do{ + if(hack_reg&1){ + q[i]-= h[j&15]; + }else{ + q[i]+= h[j&15]; + } + --j; + hack_reg>>= 1; + }while(i--!=0); + }while(c--!=0); + dump_x(q, 16, 'W'); + for(i=0; i<16; ++i){ + q[i] = s[i%5](q[i]); + } +#if TWEAK + for(i=0; i<16; ++i){ + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; } - r.v64 += bmw_large_s5(q[j+14]); - r.v64 += bmw_large_s4(q[j+15]); - r.v64 += ((uint64_t*)m)[j]; - r.v64 += ((uint64_t*)m)[(j+3)%16]; - r.v64 -= ((uint64_t*)m)[(j+10)%16]; - return r.v64; + for(i=0; i<16; ++i){ + q[i] += h[(i+1)&0xf]; + } +#endif /* TWEAK */ } +#endif /* F0_HACK==2 */ -#if F0_HACK +#if F0_HACK==1 static -uint8_t f0_lut[] PROGMEM ={ +const uint8_t f0_lut[] PROGMEM ={ 5<<1, ( 7<<1)+1, (10<<1)+0, (13<<1)+0, (14<<1)+0, 6<<1, ( 8<<1)+1, (11<<1)+0, (14<<1)+0, (15<<1)+1, 0<<1, ( 7<<1)+0, ( 9<<1)+0, (12<<1)+1, (15<<1)+0, 0<<1, ( 1<<1)+1, ( 8<<1)+0, (10<<1)+1, (13<<1)+0, 1<<1, ( 2<<1)+0, ( 9<<1)+0, (11<<1)+1, (14<<1)+1, 3<<1, ( 2<<1)+1, (10<<1)+0, (12<<1)+1, (15<<1)+0, - 4<<1, ( 0<<1)+1, ( 3<<1)+1, (11<<1)+1, (13<<1)+0, + 4<<1, ( 0<<1)+1, ( 3<<1)+1, (11<<1)+1, (13<<1)+0, 1<<1, ( 4<<1)+1, ( 5<<1)+1, (12<<1)+1, (14<<1)+1, 2<<1, ( 5<<1)+1, ( 6<<1)+1, (13<<1)+0, (15<<1)+1, 0<<1, ( 3<<1)+1, ( 6<<1)+0, ( 7<<1)+1, (14<<1)+0, @@ -250,12 +374,13 @@ uint8_t f0_lut[] PROGMEM ={ 12<<1, ( 4<<1)+1, ( 6<<1)+1, ( 9<<1)+1, (13<<1)+0 }; -void bmw_large_f0(uint64_t* q, uint64_t* h, const void* m){ +static +void bmw_large_f0(uint64_t *q, const uint64_t *h, const void *m){ uint8_t i,j=-1,v,sign,l=0; uint64_t(*s[])(uint64_t)={ bmw_large_s0, bmw_large_s1, bmw_large_s2, bmw_large_s3, bmw_large_s4 }; for(i=0; i<16; ++i){ - h[i] ^= ((uint64_t*)m)[i]; + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; } dump_x(h, 16, 'T'); // memset(q, 0, 4*16); @@ -278,25 +403,35 @@ void bmw_large_f0(uint64_t* q, uint64_t* h, const void* m){ dump_x(q, 16, 'W'); for(i=0; i<16; ++i){ q[i] = s[i%5](q[i]); - } + } +#if TWEAK + for(i=0; i<16; ++i){ + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; + } + for(i=0; i<16; ++i){ + q[i] += h[(i+1)&0xf]; + } +#endif /* TWEAK */ } +#endif /* F0_HACK==1 */ -#else -void bmw_large_f0(uint64_t* q, uint64_t* h, const void* m){ +#if F0_HACK==0 +static +void bmw_large_f0(uint64_t *q, const uint64_t *h, const void *m){ uint8_t i; uint64_t(*s[])(uint64_t)={ bmw_large_s0, bmw_large_s1, bmw_large_s2, bmw_large_s3, bmw_large_s4 }; for(i=0; i<16; ++i){ - h[i] ^= ((uint64_t*)m)[i]; + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; } - dump_x(t, 16, 'T'); +// dump_x(t, 16, 'T'); q[ 0] = (h[ 5] - h[ 7] + h[10] + h[13] + h[14]); q[ 1] = (h[ 6] - h[ 8] + h[11] + h[14] - h[15]); q[ 2] = (h[ 0] + h[ 7] + h[ 9] - h[12] + h[15]); q[ 3] = (h[ 0] - h[ 1] + h[ 8] - h[10] + h[13]); q[ 4] = (h[ 1] + h[ 2] + h[ 9] - h[11] - h[14]); q[ 5] = (h[ 3] - h[ 2] + h[10] - h[12] + h[15]); - q[ 6] = (h[ 4] - h[ 0] - h[ 3] - h[11] + h[13]); + q[ 6] = (h[ 4] - h[ 0] - h[ 3] - h[11] + h[13]); q[ 7] = (h[ 1] - h[ 4] - h[ 5] - h[12] - h[14]); q[ 8] = (h[ 2] - h[ 5] - h[ 6] + h[13] - h[15]); q[ 9] = (h[ 0] - h[ 3] + h[ 6] - h[ 7] + h[14]); @@ -305,24 +440,35 @@ void bmw_large_f0(uint64_t* q, uint64_t* h, const void* m){ q[12] = (h[ 1] + h[ 3] - h[ 6] - h[ 9] + h[10]); q[13] = (h[ 2] + h[ 4] + h[ 7] + h[10] + h[11]); q[14] = (h[ 3] - h[ 5] + h[ 8] - h[11] - h[12]); - q[15] = (h[12] - h[ 4] - h[ 6] - h[ 9] + h[13]); + q[15] = (h[12] - h[ 4] - h[ 6] - h[ 9] + h[13]); dump_x(q, 16, 'W'); for(i=0; i<16; ++i){ q[i] = s[i%5](q[i]); - } + } +#if TWEAK + for(i=0; i<16; ++i){ + ((uint64_t*)h)[i] ^= ((uint64_t*)m)[i]; + } + for(i=0; i<16; ++i){ + q[i] += h[(i+1)&0xf]; + } +#endif /* TWEAK */ + } -#endif +#endif /* F0_HACK==0 */ -void bmw_large_f1(uint64_t* q, const void* m){ +static +void bmw_large_f1(uint64_t *q, const void *m, const uint64_t *h){ uint8_t i; - q[16] = bmw_large_expand1(0, q, m); - q[17] = bmw_large_expand1(1, q, m); + q[16] = bmw_large_expand1(0, q, m, h); + q[17] = bmw_large_expand1(1, q, m, h); for(i=2; i<16; ++i){ - q[16+i] = bmw_large_expand2(i, q, m); + q[16+i] = bmw_large_expand2(i, q, m, h); } } -void bmw_large_f2(uint64_t* h, const uint64_t* q, const void* m){ +static +void bmw_large_f2(uint64_t *h, const uint64_t *q, const void *m){ uint64_t xl=0, xh; uint8_t i; for(i=16;i<24;++i){ @@ -332,7 +478,7 @@ void bmw_large_f2(uint64_t* h, const uint64_t* q, const void* m){ for(i=24;i<32;++i){ xh ^= q[i]; } -#if DEBUG +#if DEBUG cli_putstr_P(PSTR("\r\n XL = ")); cli_hexdump_rev(&xl, 4); cli_putstr_P(PSTR("\r\n XH = ")); @@ -364,51 +510,66 @@ void bmw_large_f2(uint64_t* h, const uint64_t* q, const void* m){ h[15] += SHR64(xl, 2) ^ q[22] ^ q[15]; } -void bmw_large_nextBlock(bmw_large_ctx_t* ctx, const void* block){ +void bmw_large_nextBlock(bmw_large_ctx_t *ctx, const void *block){ uint64_t q[32]; dump_x(block, 16, 'M'); bmw_large_f0(q, ctx->h, block); dump_x(q, 16, 'Q'); - bmw_large_f1(q, block); + bmw_large_f1(q, block, ctx->h); dump_x(q, 32, 'Q'); bmw_large_f2(ctx->h, q, block); ctx->counter += 1; ctx_dump(ctx); } -void bmw_large_lastBlock(bmw_large_ctx_t* ctx, const void* block, uint16_t length_b){ - uint8_t buffer[128]; +void bmw_large_lastBlock(bmw_large_ctx_t *ctx, const void *block, uint16_t length_b){ + union { + uint8_t v8[128]; + uint64_t v64[ 16]; + } buffer; while(length_b >= BMW_LARGE_BLOCKSIZE){ bmw_large_nextBlock(ctx, block); length_b -= BMW_LARGE_BLOCKSIZE; block = (uint8_t*)block + BMW_LARGE_BLOCKSIZE_B; } - memset(buffer, 0, 128); - memcpy(buffer, block, (length_b+7)/8); - buffer[length_b>>3] |= 0x80 >> (length_b&0x07); + memset(buffer.v8, 0, 128); + memcpy(buffer.v8, block, (length_b+7)/8); + buffer.v8[length_b>>3] |= 0x80 >> (length_b&0x07); if(length_b+1>128*8-64){ - bmw_large_nextBlock(ctx, buffer); - memset(buffer, 0, 128-8); + bmw_large_nextBlock(ctx, buffer.v8); + memset(buffer.v8, 0, 128-8); ctx->counter -= 1; } - *((uint64_t*)&(buffer[128-8])) = (uint64_t)(ctx->counter*1024LL)+(uint64_t)length_b; - bmw_large_nextBlock(ctx, buffer); + buffer.v64[15] = (uint64_t)(ctx->counter*1024LL)+(uint64_t)length_b; + bmw_large_nextBlock(ctx, buffer.v8); +#if TWEAK + uint8_t i; + uint64_t q[32]; + memset(buffer.v8, 0xaa, 128); + for(i=0; i<16; ++i){ + buffer.v8[8*i] = i + 0xa0; + } + bmw_large_f0(q, buffer.v64, ctx->h); + bmw_large_f1(q, ctx->h, buffer.v64); + bmw_large_f2(buffer.v64, q, ctx->h); + memcpy(ctx->h, buffer.v8, 128); +#endif } -void bmw384_init(bmw384_ctx_t* ctx){ +void bmw384_init(bmw384_ctx_t *ctx){ uint8_t i; ctx->h[0] = 0x0001020304050607LL; for(i=1; i<16; ++i){ ctx->h[i] = ctx->h[i-1]+ 0x0808080808080808LL; } -#if BUG24 +#if BUG24 ctx->h[6] = 0x3031323324353637LL; #endif ctx->counter=0; ctx_dump(ctx); } -void bmw512_init(bmw512_ctx_t* ctx){ +void bmw512_init(bmw512_ctx_t *ctx){ uint8_t i; ctx->h[0] = 0x8081828384858687LL; for(i=1; i<16; ++i){ @@ -418,31 +579,31 @@ void bmw512_init(bmw512_ctx_t* ctx){ ctx_dump(ctx); } -void bmw384_nextBlock(bmw384_ctx_t* ctx, const void* block){ +void bmw384_nextBlock(bmw384_ctx_t *ctx, const void *block){ bmw_large_nextBlock(ctx, block); } -void bmw512_nextBlock(bmw512_ctx_t* ctx, const void* block){ +void bmw512_nextBlock(bmw512_ctx_t *ctx, const void *block){ bmw_large_nextBlock(ctx, block); } -void bmw384_lastBlock(bmw384_ctx_t* ctx, const void* block, uint16_t length_b){ +void bmw384_lastBlock(bmw384_ctx_t *ctx, const void *block, uint16_t length_b){ bmw_large_lastBlock(ctx, block, length_b); } -void bmw512_lastBlock(bmw512_ctx_t* ctx, const void* block, uint16_t length_b){ +void bmw512_lastBlock(bmw512_ctx_t *ctx, const void *block, uint16_t length_b){ bmw_large_lastBlock(ctx, block, length_b); } -void bmw384_ctx2hash(void* dest, const bmw384_ctx_t* ctx){ +void bmw384_ctx2hash(void *dest, const bmw384_ctx_t *ctx){ memcpy(dest, &(ctx->h[10]), 384/8); } -void bmw512_ctx2hash(void* dest, const bmw512_ctx_t* ctx){ +void bmw512_ctx2hash(void *dest, const bmw512_ctx_t *ctx){ memcpy(dest, &(ctx->h[8]), 512/8); } -void bmw384(void* dest, const void* msg, uint32_t length_b){ +void bmw384(void *dest, const void *msg, uint32_t length_b){ bmw_large_ctx_t ctx; bmw384_init(&ctx); while(length_b>=BMW_LARGE_BLOCKSIZE){ @@ -454,7 +615,7 @@ void bmw384(void* dest, const void* msg, uint32_t length_b){ bmw384_ctx2hash(dest, &ctx); } -void bmw512(void* dest, const void* msg, uint32_t length_b){ +void bmw512(void *dest, const void *msg, uint32_t length_b){ bmw_large_ctx_t ctx; bmw512_init(&ctx); while(length_b>=BMW_LARGE_BLOCKSIZE){