ref: ee4b58548e0df76a402c09ffcf0964d0e6cddbfa
dir: /libsec/salsa.c/
#include <u.h> #include <libc.h> #include <libsec.h> enum{ Blockwords= SalsaBsize/sizeof(u32int) }; /* little-endian data order */ #define GET4(p) ((((((p)[3]<<8) | (p)[2])<<8) | (p)[1])<<8 | (p)[0]) #define PUT4(p, v) (((p)[0]=v), (v>>=8), ((p)[1]=v), (v>>=8), ((p)[2]=v), (v>>=8), ((p)[3]=v)) #define ROTATE(v,c) (t = v, (u32int)(t << (c)) | (t >> (32 - (c)))) #define ENCRYPT(s, x, y, d) {\ u32int v; \ uchar *sp, *dp; \ sp = (s); \ v = GET4(sp); \ v ^= (x)+(y); \ dp = (d); \ PUT4(dp, v); \ } static uchar sigma[16] = "expand 32-byte k"; static uchar tau[16] = "expand 16-byte k"; static void load(u32int *d, uchar *s, int nw) { int i; for(i = 0; i < nw; i++, s+=4) d[i] = GET4(s); } void setupSalsastate(Salsastate *s, uchar *key, ulong keylen, uchar *iv, ulong ivlen, int rounds) { if(keylen != 256/8 && keylen != 128/8) sysfatal("invalid salsa key length"); if(ivlen != 64/8 && ivlen != 128/8 && ivlen != 192/8) sysfatal("invalid salsa iv length"); if(rounds == 0) rounds = 20; s->rounds = rounds; if(keylen == 256/8) { /* recommended */ load(&s->input[0], sigma+4*0, 1); load(&s->input[1], key +16*0, 4); load(&s->input[5], sigma+4*1, 1); load(&s->input[10], sigma+4*2, 1); load(&s->input[11], key +16*1, 4); load(&s->input[15], sigma+4*3, 1); }else{ load(&s->input[0], tau +4*0, 1); load(&s->input[1], key, 4); load(&s->input[5], tau +4*1, 1); load(&s->input[10], tau +4*2, 1); load(&s->input[11], key, 4); load(&s->input[15], tau +4*3, 1); } s->key[0] = s->input[1]; s->key[1] = s->input[2]; s->key[2] = s->input[3]; s->key[3] = s->input[4]; s->key[4] = s->input[11]; s->key[5] = s->input[12]; s->key[6] = s->input[13]; s->key[7] = s->input[14]; s->ivwords = ivlen/4; s->input[8] = 0; s->input[9] = 0; if(iv == nil){ s->input[6] = 0; s->input[7] = 0; }else salsa_setiv(s, iv); } static void hsalsablock(uchar h[32], Salsastate *s) { u32int x[Blockwords], t; int i, rounds; rounds = s->rounds; x[0] = s->input[0]; x[1] = s->input[1]; x[2] = s->input[2]; x[3] = s->input[3]; x[4] = s->input[4]; x[5] = s->input[5]; x[6] = s->input[6]; x[7] = s->input[7]; x[8] = s->input[8]; x[9] = s->input[9]; x[10] = s->input[10]; x[11] = s->input[11]; x[12] = s->input[12]; x[13] = s->input[13]; x[14] = s->input[14]; x[15] = s->input[15]; for(i = rounds; i > 0; i -= 2) { x[4] ^= ROTATE( x[0]+x[12], 7); x[8] ^= ROTATE( x[4]+ x[0], 9); x[12] ^= ROTATE( x[8]+ x[4],13); x[0] ^= ROTATE(x[12]+ x[8],18); x[9] ^= ROTATE( x[5]+ x[1], 7); x[13] ^= ROTATE( x[9]+ x[5], 9); x[1] ^= ROTATE(x[13]+ x[9],13); x[5] ^= ROTATE( x[1]+x[13],18); x[14] ^= ROTATE(x[10]+ x[6], 7); x[2] ^= ROTATE(x[14]+x[10], 9); x[6] ^= ROTATE( x[2]+x[14],13); x[10] ^= ROTATE( x[6]+ x[2],18); x[3] ^= ROTATE(x[15]+x[11], 7); x[7] ^= ROTATE( x[3]+x[15], 9); x[11] ^= ROTATE( x[7]+ x[3],13); x[15] ^= ROTATE(x[11]+ x[7],18); x[1] ^= ROTATE( x[0]+ x[3], 7); x[2] ^= ROTATE( x[1]+ x[0], 9); x[3] ^= ROTATE( x[2]+ x[1],13); x[0] ^= ROTATE( x[3]+ x[2],18); x[6] ^= ROTATE( x[5]+ x[4], 7); x[7] ^= ROTATE( x[6]+ x[5], 9); x[4] ^= ROTATE( x[7]+ x[6],13); x[5] ^= ROTATE( x[4]+ x[7],18); x[11] ^= ROTATE(x[10]+ x[9], 7); x[8] ^= ROTATE(x[11]+x[10], 9); x[9] ^= ROTATE( x[8]+x[11],13); x[10] ^= ROTATE( x[9]+ x[8],18); x[12] ^= ROTATE(x[15]+x[14], 7); x[13] ^= ROTATE(x[12]+x[15], 9); x[14] ^= ROTATE(x[13]+x[12],13); x[15] ^= ROTATE(x[14]+x[13],18); } PUT4(h+0*4, x[0]); PUT4(h+1*4, x[5]); PUT4(h+2*4, x[10]); PUT4(h+3*4, x[15]); PUT4(h+4*4, x[6]); PUT4(h+5*4, x[7]); PUT4(h+6*4, x[8]); PUT4(h+7*4, x[9]); } void salsa_setiv(Salsastate *s, uchar *iv) { if(s->ivwords == 128/32){ /* hsalsa 128-bit iv */ load(&s->input[6], iv, 4); return; } if(s->ivwords == 192/32){ /* xsalsa with 192-bit iv */ u32int counter[2]; uchar h[32]; counter[0] = s->input[8]; counter[1] = s->input[9]; s->input[1] = s->key[0]; s->input[2] = s->key[1]; s->input[3] = s->key[2]; s->input[4] = s->key[3]; s->input[11] = s->key[4]; s->input[12] = s->key[5]; s->input[13] = s->key[6]; s->input[14] = s->key[7]; load(&s->input[6], iv, 4); hsalsablock(h, s); load(&s->input[1], h+16*0, 4); load(&s->input[11], h+16*1, 4); memset(h, 0, 32); s->input[8] = counter[0]; s->input[9] = counter[1]; iv += 16; } /* 64-bit iv */ load(&s->input[6], iv, 2); } void salsa_setblock(Salsastate *s, u64int blockno) { s->input[8] = blockno; s->input[9] = blockno>>32; } static void encryptblock(Salsastate *s, uchar *src, uchar *dst) { u32int x[Blockwords], t; int i, rounds; rounds = s->rounds; x[0] = s->input[0]; x[1] = s->input[1]; x[2] = s->input[2]; x[3] = s->input[3]; x[4] = s->input[4]; x[5] = s->input[5]; x[6] = s->input[6]; x[7] = s->input[7]; x[8] = s->input[8]; x[9] = s->input[9]; x[10] = s->input[10]; x[11] = s->input[11]; x[12] = s->input[12]; x[13] = s->input[13]; x[14] = s->input[14]; x[15] = s->input[15]; for(i = rounds; i > 0; i -= 2) { x[4] ^= ROTATE( x[0]+x[12], 7); x[8] ^= ROTATE( x[4]+ x[0], 9); x[12] ^= ROTATE( x[8]+ x[4],13); x[0] ^= ROTATE(x[12]+ x[8],18); x[9] ^= ROTATE( x[5]+ x[1], 7); x[13] ^= ROTATE( x[9]+ x[5], 9); x[1] ^= ROTATE(x[13]+ x[9],13); x[5] ^= ROTATE( x[1]+x[13],18); x[14] ^= ROTATE(x[10]+ x[6], 7); x[2] ^= ROTATE(x[14]+x[10], 9); x[6] ^= ROTATE( x[2]+x[14],13); x[10] ^= ROTATE( x[6]+ x[2],18); x[3] ^= ROTATE(x[15]+x[11], 7); x[7] ^= ROTATE( x[3]+x[15], 9); x[11] ^= ROTATE( x[7]+ x[3],13); x[15] ^= ROTATE(x[11]+ x[7],18); x[1] ^= ROTATE( x[0]+ x[3], 7); x[2] ^= ROTATE( x[1]+ x[0], 9); x[3] ^= ROTATE( x[2]+ x[1],13); x[0] ^= ROTATE( x[3]+ x[2],18); x[6] ^= ROTATE( x[5]+ x[4], 7); x[7] ^= ROTATE( x[6]+ x[5], 9); x[4] ^= ROTATE( x[7]+ x[6],13); x[5] ^= ROTATE( x[4]+ x[7],18); x[11] ^= ROTATE(x[10]+ x[9], 7); x[8] ^= ROTATE(x[11]+x[10], 9); x[9] ^= ROTATE( x[8]+x[11],13); x[10] ^= ROTATE( x[9]+ x[8],18); x[12] ^= ROTATE(x[15]+x[14], 7); x[13] ^= ROTATE(x[12]+x[15], 9); x[14] ^= ROTATE(x[13]+x[12],13); x[15] ^= ROTATE(x[14]+x[13],18); } #ifdef FULL_UNROLL ENCRYPT(src+0*4, x[0], s->input[0], dst+0*4); ENCRYPT(src+1*4, x[1], s->input[1], dst+1*4); ENCRYPT(src+2*4, x[2], s->input[2], dst+2*4); ENCRYPT(src+3*4, x[3], s->input[3], dst+3*4); ENCRYPT(src+4*4, x[4], s->input[4], dst+4*4); ENCRYPT(src+5*4, x[5], s->input[5], dst+5*4); ENCRYPT(src+6*4, x[6], s->input[6], dst+6*4); ENCRYPT(src+7*4, x[7], s->input[7], dst+7*4); ENCRYPT(src+8*4, x[8], s->input[8], dst+8*4); ENCRYPT(src+9*4, x[9], s->input[9], dst+9*4); ENCRYPT(src+10*4, x[10], s->input[10], dst+10*4); ENCRYPT(src+11*4, x[11], s->input[11], dst+11*4); ENCRYPT(src+12*4, x[12], s->input[12], dst+12*4); ENCRYPT(src+13*4, x[13], s->input[13], dst+13*4); ENCRYPT(src+14*4, x[14], s->input[14], dst+14*4); ENCRYPT(src+15*4, x[15], s->input[15], dst+15*4); #else for(i=0; i<nelem(x); i+=4){ ENCRYPT(src, x[i], s->input[i], dst); ENCRYPT(src+4, x[i+1], s->input[i+1], dst+4); ENCRYPT(src+8, x[i+2], s->input[i+2], dst+8); ENCRYPT(src+12, x[i+3], s->input[i+3], dst+12); src += 16; dst += 16; } #endif if(++s->input[8] == 0) s->input[9]++; } void salsa_encrypt2(uchar *src, uchar *dst, ulong bytes, Salsastate *s) { uchar tmp[SalsaBsize]; for(; bytes >= SalsaBsize; bytes -= SalsaBsize){ encryptblock(s, src, dst); src += SalsaBsize; dst += SalsaBsize; } if(bytes > 0){ memmove(tmp, src, bytes); encryptblock(s, tmp, tmp); memmove(dst, tmp, bytes); } } void salsa_encrypt(uchar *buf, ulong bytes, Salsastate *s) { salsa_encrypt2(buf, buf, bytes, s); } void hsalsa(uchar h[32], uchar *key, ulong keylen, uchar nonce[16], int rounds) { Salsastate s[1]; setupSalsastate(s, key, keylen, nonce, 16, rounds); hsalsablock(h, s); memset(s, 0, sizeof(s)); }