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- /*
- * This code is based on Ted Krovetz's ChaCha implementation; details below.
- *
- * Note that I've ripped out all of the code that wasn't suitable for doing
- * block-oriented operation, all (residual) support for 128-bit ChaCha keys,
- * all (partial) support for counter values over 32 bits, the ability to xor
- * the stream with a plaintext, and so on.
- *
- * Future versions of this might remove bigendian conversions too. DO NOT use
- * this code for your stream cipher: go back to the original source. (I got
- * this copy from SUPERCOP).
- */
-
- /* Chacha implementation for 16-byte vectors by Ted Krovetz (ted@krovetz.net).
- * Assumes 32-bit int, 64-bit long long. Public domain. Modified: 2012.07.26.
- * Chacha is an improvement on the stream cipher Salsa, described at
- * http://cr.yp.to/papers.html#chacha
- */
- #include <string.h>
- #include <assert.h>
- #include "ottery-internal.h"
-
- /* Architecture-neutral way to specify 16-byte vector of ints */
- typedef unsigned vec __attribute__ ((vector_size (16)));
-
- /* This implementation is designed for Neon, SSE and AltiVec machines. The
- * following specify how to do certain vector operations efficiently on
- * each architecture, using intrinsics.
- * This implementation supports parallel processing of multiple blocks,
- * including potentially using general-purpose registers.
- */
- #if __ARM_NEON__
- #include <arm_neon.h>
- #define GPR_TOO 1
- #define VBPI 2
- #define ONE (vec)vsetq_lane_u32(1,vdupq_n_u32(0),0)
- #define NONCE(ctr,p) (vec)vcombine_u32(vcreate_u32(ctr),vcreate_u32(*(uint64_t *)p))
- #define ROTV1(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,1)
- #define ROTV2(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,2)
- #define ROTV3(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,3)
- #define ROTW16(x) (vec)vrev32q_u16((uint16x8_t)x)
- #if __clang__
- #define ROTW7(x) (x << ((vec){ 7, 7, 7, 7})) ^ (x >> ((vec){25,25,25,25}))
- #define ROTW8(x) (x << ((vec){ 8, 8, 8, 8})) ^ (x >> ((vec){24,24,24,24}))
- #define ROTW12(x) (x << ((vec){12,12,12,12})) ^ (x >> ((vec){20,20,20,20}))
- #else
- #define ROTW7(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,7),(uint32x4_t)x,25)
- #define ROTW8(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,8),(uint32x4_t)x,24)
- #define ROTW12(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,12),(uint32x4_t)x,20)
- #endif
- #elif __ALTIVEC__
- #include <altivec.h>
- #define GPR_TOO 1
- #define VBPI 3
- #define ONE ((vec){1,0,0,0})
- #define NONCE(ctr,p) vec_sro(*(vec *)p, (vector char)(vec){0,0,0,8*8})+((vec){((ctr)&0xffffffff), (ctr)>>32, 0, 0})
- #error "Don't use this code till it can be tested on altivec"
- #define REVW_BE(x) __builtin_bswap32(x)
- #define REVV_BE(x) vec_perm(x,x,(vector char){3,2,1,0,7,6,5,4,11,10,9,8,15,14,13,12})
- #define ROTV1(x) vec_perm(x,x,(vector char){4,5,6,7,8,9,10,11,12,13,14,15,0,1,2,3})
- #define ROTV2(x) vec_perm(x,x,(vector char){8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7})
- #define ROTV3(x) vec_perm(x,x,(vector char){12,13,14,15,0,1,2,3,4,5,6,7,8,9,10,11})
- #define ROTW7(x) vec_rl(x,vec_splat_u32(7))
- #define ROTW8(x) vec_rl(x,vec_splat_u32(8))
- #define ROTW12(x) vec_rl(x,vec_splat_u32(12))
- #define ROTW16(x) vec_rl(x,vec_splat_u32(-16)) /* trick to get 16 */
- #elif __SSE2__
- #include <emmintrin.h>
- #define GPR_TOO 0
- #if __clang__
- #define VBPI 4
- #else
- #define VBPI 3
- #endif
- #define ONE (vec)_mm_set_epi32(0,0,0,1)
- #define NONCE(ctr,p) (vec)(_mm_slli_si128(_mm_loadl_epi64((__m128i *)(p)),8)+_mm_set_epi64x(0,ctr))
- #define ROTV1(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(0,3,2,1))
- #define ROTV2(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(1,0,3,2))
- #define ROTV3(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(2,1,0,3))
- #define ROTW7(x) (vec)(_mm_slli_epi32((__m128i)x, 7) ^ _mm_srli_epi32((__m128i)x,25))
- #define ROTW12(x) (vec)(_mm_slli_epi32((__m128i)x,12) ^ _mm_srli_epi32((__m128i)x,20))
- #if __SSSE3__
- #include <tmmintrin.h>
- #define ROTW8(x) (vec)_mm_shuffle_epi8((__m128i)x,_mm_set_epi8(14,13,12,15,10,9,8,11,6,5,4,7,2,1,0,3))
- #define ROTW16(x) (vec)_mm_shuffle_epi8((__m128i)x,_mm_set_epi8(13,12,15,14,9,8,11,10,5,4,7,6,1,0,3,2))
- #else
- #define ROTW8(x) (vec)(_mm_slli_epi32((__m128i)x, 8) ^ _mm_srli_epi32((__m128i)x,24))
- #define ROTW16(x) (vec)(_mm_slli_epi32((__m128i)x,16) ^ _mm_srli_epi32((__m128i)x,16))
- #endif
- #else
- #error -- Implementation supports only machines with neon, altivec or SSE2
- #endif
-
- #ifndef REVV_BE
- #define REVV_BE(x) (x)
- #endif
-
- #ifndef REVW_BE
- #define REVW_BE(x) (x)
- #endif
-
- #define BPI (VBPI + GPR_TOO) /* Blocks computed per loop iteration */
-
- #define DQROUND_VECTORS(a,b,c,d) \
- a += b; d ^= a; d = ROTW16(d); \
- c += d; b ^= c; b = ROTW12(b); \
- a += b; d ^= a; d = ROTW8(d); \
- c += d; b ^= c; b = ROTW7(b); \
- b = ROTV1(b); c = ROTV2(c); d = ROTV3(d); \
- a += b; d ^= a; d = ROTW16(d); \
- c += d; b ^= c; b = ROTW12(b); \
- a += b; d ^= a; d = ROTW8(d); \
- c += d; b ^= c; b = ROTW7(b); \
- b = ROTV3(b); c = ROTV2(c); d = ROTV1(d);
-
- #define QROUND_WORDS(a,b,c,d) \
- a = a+b; d ^= a; d = d<<16 | d>>16; \
- c = c+d; b ^= c; b = b<<12 | b>>20; \
- a = a+b; d ^= a; d = d<< 8 | d>>24; \
- c = c+d; b ^= c; b = b<< 7 | b>>25;
-
- #define WRITE(op, d, v0, v1, v2, v3) \
- *(vec *)(op + d + 0) = REVV_BE(v0); \
- *(vec *)(op + d + 4) = REVV_BE(v1); \
- *(vec *)(op + d + 8) = REVV_BE(v2); \
- *(vec *)(op + d + 12) = REVV_BE(v3);
-
- struct chacha_state_krovetz {
- __attribute__ ((aligned (16))) uint8_t key[32];
- __attribute__ ((aligned (16))) uint8_t nonce[8];
- };
-
- #define LOOP_ITERATIONS 4
-
- static inline int
- ottery_blocks_chacha_krovetz(
- const int chacha_rounds,
- uint8_t *out,
- uint32_t block_idx,
- struct chacha_state_krovetz *st)
- __attribute__((always_inline));
-
- /** Generates 64 * BPI * LOOP_ITERATIONS bytes of output using the key and
- * nonce in st and the counter in block_idx, and store them in out.
- */
- static inline int
- ottery_blocks_chacha_krovetz(
- const int chacha_rounds,
- uint8_t *out,
- uint32_t block_idx,
- struct chacha_state_krovetz *st)
- /* Assumes all pointers are aligned properly for vector reads */
- {
- const unsigned char *k = st->key;
- const unsigned char *n = st->nonce;
- unsigned i, j, *op=(unsigned *)out, *kp, *np;
- __attribute__ ((aligned (16))) unsigned chacha_const[] =
- {0x61707865,0x3320646E,0x79622D32,0x6B206574};
- #if ( __ARM_NEON__ || __SSE2__)
- kp = (unsigned *)k;
- np = (unsigned *)n;
- #else
- __attribute__ ((aligned (16))) unsigned key[8], nonce[2];
- ((vec *)key)[0] = REVV_BE(((vec *)k)[0]);
- ((vec *)key)[1] = REVV_BE(((vec *)k)[1]);
- nonce[0] = REVW_BE(((unsigned *)n)[0]);
- nonce[1] = REVW_BE(((unsigned *)n)[1]);
- kp = (unsigned *)key;
- np = (unsigned *)nonce;
- #endif
- vec s0 = *(vec *)chacha_const;
- vec s1 = ((vec *)kp)[0];
- vec s2 = ((vec *)kp)[1];
- vec s3 = NONCE(block_idx, np);
- for (j = 0; j < LOOP_ITERATIONS; ++j) {
- vec v0,v1,v2,v3,v4,v5,v6,v7;
- v4 = v0 = s0; v5 = v1 = s1; v6 = v2 = s2; v3 = s3;
- v7 = v3 + ONE;
- #if VBPI > 2
- vec v8,v9,v10,v11;
- v8 = v4; v9 = v5; v10 = v6;
- v11 = v7 + ONE;
- #endif
- #if VBPI > 3
- vec v12,v13,v14,v15;
- v12 = v8; v13 = v9; v14 = v10;
- v15 = v11 + ONE;
- #endif
- #if GPR_TOO
- register unsigned x0, x1, x2, x3, x4, x5, x6, x7, x8,
- x9, x10, x11, x12, x13, x14, x15;
- x0 = chacha_const[0]; x1 = chacha_const[1];
- x2 = chacha_const[2]; x3 = chacha_const[3];
- x4 = kp[0]; x5 = kp[1]; x6 = kp[2]; x7 = kp[3];
- x8 = kp[4]; x9 = kp[5]; x10 = kp[6]; x11 = kp[7];
- const uint64_t x_ctr = block_idx + BPI*iters+(BPI-1);
- x12 = x_ctr & 0xffffffff; x13 = x_ctr>>32; x14 = np[0]; x15 = np[1];
- #endif
- for (i = chacha_rounds/2; i; i--) {
- DQROUND_VECTORS(v0,v1,v2,v3)
- DQROUND_VECTORS(v4,v5,v6,v7)
- #if VBPI > 2
- DQROUND_VECTORS(v8,v9,v10,v11)
- #endif
- #if VBPI > 3
- DQROUND_VECTORS(v12,v13,v14,v15)
- #endif
- #if GPR_TOO
- QROUND_WORDS( x0, x4, x8,x12)
- QROUND_WORDS( x1, x5, x9,x13)
- QROUND_WORDS( x2, x6,x10,x14)
- QROUND_WORDS( x3, x7,x11,x15)
- QROUND_WORDS( x0, x5,x10,x15)
- QROUND_WORDS( x1, x6,x11,x12)
- QROUND_WORDS( x2, x7, x8,x13)
- QROUND_WORDS( x3, x4, x9,x14)
- #endif
- }
- WRITE(op, 0, v0+s0, v1+s1, v2+s2, v3+s3)
- s3 += ONE;
- WRITE(op, 16, v4+s0, v5+s1, v6+s2, v7+s3)
- s3 += ONE;
- #if VBPI > 2
- WRITE(op, 32, v8+s0, v9+s1, v10+s2, v11+s3)
- s3 += ONE;
- #endif
- #if VBPI > 3
- WRITE(op, 48, v12+s0, v13+s1, v14+s2, v15+s3)
- s3 += ONE;
- #endif
- op += VBPI*16;
- #if GPR_TOO
- op[0] = REVW_BE((x0 + chacha_const[0]));
- op[1] = REVW_BE((x1 + chacha_const[1]));
- op[2] = REVW_BE((x2 + chacha_const[2]));
- op[3] = REVW_BE((x3 + chacha_const[3]));
- op[4] = REVW_BE((x4 + kp[0]));
- op[5] = REVW_BE((x5 + kp[1]));
- op[6] = REVW_BE((x6 + kp[2]));
- op[7] = REVW_BE((x7 + kp[3]));
- op[8] = REVW_BE((x8 + kp[4]));
- op[9] = REVW_BE((x9 + kp[5]));
- op[10] = REVW_BE((x10 + kp[6]));
- op[11] = REVW_BE((x11 + kp[7]));
- op[12] = REVW_BE((x12 + (x_ctr & 0xffffffff)));
- op[13] = REVW_BE((x13 + (x_ctr >> 32)));
- op[14] = REVW_BE((x14 + np[0]));
- op[15] = REVW_BE((x15 + np[1]));
- s3 += ONE;
- op += 16;
- #endif
- }
- return 0;
- }
-
- #define STATE_LEN (sizeof(struct chacha_state_krovetz))
- #define STATE_BYTES 40
- #define IDX_STEP (BPI * LOOP_ITERATIONS)
- #define OUTPUT_LEN (IDX_STEP * 64)
-
- static void
- chacha_krovetz_state_setup(void *state, const uint8_t *bytes)
- {
- struct chacha_state_krovetz *st = state;
- memcpy(st->key, bytes, 32);
- memcpy(st->nonce, bytes+32, 8);
- }
-
- static void
- chacha8_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
- {
- struct chacha_state_krovetz *st = state;
- ottery_blocks_chacha_krovetz(8, output, idx * IDX_STEP, st);
- }
-
- static void
- chacha12_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
- {
- struct chacha_state_krovetz *st = state;
- ottery_blocks_chacha_krovetz(12, output, idx * IDX_STEP, st);
- }
-
- static void
- chacha20_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
- {
- struct chacha_state_krovetz *st = state;
- ottery_blocks_chacha_krovetz(20, output, idx * IDX_STEP, st);
- }
-
- #ifdef __SSSE3__
- #define NEED_CPUCAP OTTERY_CPUCAP_SSSE3|OTTERY_CPUCAP_SIMD
- #define FLAV "-SSSE3"
- #else
- #define NEED_CPUCAP OTTERY_CPUCAP_SIMD
- #define FLAV "-DEFAULT"
- #endif
-
- #define PRF_CHACHA(r) { \
- "CHACHA" #r, \
- "CHACHA" #r "-SIMD", \
- "CHACHA" #r "-SIMD" FLAV, \
- STATE_LEN, \
- STATE_BYTES, \
- OUTPUT_LEN, \
- NEED_CPUCAP, \
- chacha_krovetz_state_setup, \
- chacha ## r ## _krovetz_generate \
- }
-
- #if defined OTTERY_BUILDING_SIMD1
- const struct ottery_prf ottery_prf_chacha8_krovetz_1_ = PRF_CHACHA(8);
- const struct ottery_prf ottery_prf_chacha12_krovetz_1_ = PRF_CHACHA(12);
- const struct ottery_prf ottery_prf_chacha20_krovetz_1_ = PRF_CHACHA(20);
- #elif defined OTTERY_BUILDING_SIMD2
- const struct ottery_prf ottery_prf_chacha8_krovetz_2_ = PRF_CHACHA(8);
- const struct ottery_prf ottery_prf_chacha12_krovetz_2_ = PRF_CHACHA(12);
- const struct ottery_prf ottery_prf_chacha20_krovetz_2_ = PRF_CHACHA(20);
- #else
- #error "Which PRF symbols am I supposed to define?"
- #endif
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