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/* spritz.c */ |
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/* (C)2015 Marc Alexander Lehmann, all rights reserved */ |
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|
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#include "spritz.h" |
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|
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#include <assert.h> |
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|
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void |
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spritz_init (spritz_state *s) |
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{ |
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s->a = |
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s->i = |
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s->j = |
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s->k = |
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s->z = 0; |
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s->w = 1; |
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|
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uint_fast8_t v = spritz_N - 1; |
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do |
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s->S[v] = v; |
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while (v--); |
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} |
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|
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void |
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spritz_update (spritz_state *s) |
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{ |
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s->i += s->w; |
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s->j = s->k + s->S[s->j + s->S[s->i]]; |
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s->k = s->k + s->i + s->S[s->j]; |
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SPRITZ_SWAP (s->S[s->i], s->S[s->j]); |
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} |
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|
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void |
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spritz_whip (spritz_state *s, uint_fast16_t r) |
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{ |
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while (r--) |
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spritz_update (s); |
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|
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s->w += 2; |
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} |
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|
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#define SPRITZ_SWAP(a,b) { uint8_t ss_c = (a); (a) = (b); (b) = ss_c; } |
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|
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void |
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spritz_crush (spritz_state *s) |
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{ |
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uint_fast16_t v; |
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|
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for (v = 0; v < (spritz_N >> 1); ++v) |
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if (s->S[v] > s->S[spritz_N - 1 - v]) |
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SPRITZ_SWAP (s->S[v], s->S[spritz_N - 1 - v]); |
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} |
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|
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void |
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spritz_shuffle (spritz_state *s) |
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{ |
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spritz_whip (s, 2 * spritz_N); spritz_crush (s); |
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spritz_whip (s, 2 * spritz_N); spritz_crush (s); |
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spritz_whip (s, 2 * spritz_N); |
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|
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s->a = 0; |
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} |
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|
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static void |
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spritz_shuffle_absorb (spritz_state *s) |
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{ |
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if (s->a == (spritz_N >> 1)) |
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spritz_shuffle (s); |
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} |
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|
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void |
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spritz_absorb_nibble (spritz_state *s, uint8_t x) |
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{ |
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spritz_shuffle_absorb (s); |
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|
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SPRITZ_SWAP (s->S[s->a], s->S[(spritz_N >> 1) + x]); |
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++s->a; |
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} |
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|
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static void |
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spritz_absorb_byte (spritz_state *s, uint8_t b) |
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{ |
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spritz_absorb_nibble (s, b & 15); |
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spritz_absorb_nibble (s, b >> 4); |
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} |
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|
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void |
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spritz_absorb (spritz_state *s, const void *I, size_t I_len) |
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{ |
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uint8_t *i = (uint8_t *)I; |
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|
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while (I_len--) |
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spritz_absorb_byte (s, *i++); |
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} |
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|
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void |
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spritz_absorb_stop (spritz_state *s) |
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{ |
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spritz_shuffle_absorb (s); |
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|
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++s->a; |
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} |
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|
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// commonly used helper function |
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void |
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spritz_absorb_and_stop (spritz_state *s, const void *I, size_t I_len) |
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{ |
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spritz_absorb (s, I, I_len); |
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spritz_absorb_stop (s); |
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} |
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|
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static void |
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spritz_shuffle_squeeze (spritz_state *s) |
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{ |
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if (s->a) |
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spritz_shuffle (s); |
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} |
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|
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uint8_t |
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spritz_output (spritz_state *s) |
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{ |
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return s->S[s->j + s->S[s->i + s->S[s->z + s->k]]]; |
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} |
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|
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// slightly faster internal helper, drip without squeeze preparation |
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static uint8_t |
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spritz_drip_nosqueeze (spritz_state *s) |
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{ |
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spritz_update (s); |
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return spritz_output (s); |
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} |
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|
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void |
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spritz_squeeze (spritz_state *s, void *P, size_t P_len) |
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{ |
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spritz_shuffle_squeeze (s); |
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|
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uint8_t *p = (uint8_t *)P; |
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|
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while (P_len--) |
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*p++ = spritz_drip_nosqueeze (s); |
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} |
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|
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uint8_t |
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spritz_drip (spritz_state *s) |
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{ |
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spritz_shuffle_squeeze (s); |
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|
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return spritz_drip_nosqueeze (s); |
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} |
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|
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void |
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spritz_xor_init (spritz_state *s, const void *K, size_t K_len, const void *IV, size_t IV_len) |
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{ |
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spritz_init (s); |
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|
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spritz_absorb (s, K, K_len); |
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|
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if (IV) |
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{ |
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spritz_absorb_stop (s); |
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spritz_absorb (s, IV, IV_len); |
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} |
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|
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spritz_shuffle_squeeze (s); |
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} |
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|
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void |
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spritz_xor_crypt (spritz_state *s, const void *I, void *O, size_t len) |
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{ |
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const uint8_t *i = (const uint8_t *)I; |
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uint8_t *o = ( uint8_t *)O; |
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|
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while (len--) |
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*o++ = *i++ ^ spritz_drip_nosqueeze (s); |
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} |
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|
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void |
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spritz_hash_finish (spritz_state *s, void *H, size_t H_len) |
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{ |
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spritz_absorb_stop (s); |
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assert (H_len <= 0xff); |
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spritz_absorb_byte (s, H_len); |
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|
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spritz_squeeze (s, H, H_len); |
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} |
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|
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void |
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spritz_mac_init (spritz_state *s, const void *K, size_t K_len) |
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{ |
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spritz_init (s); |
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spritz_absorb_and_stop (s, K, K_len); |
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} |
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|
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void |
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spritz_aead_init (spritz_state *s, const void *K, size_t K_len) |
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{ |
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spritz_mac_init (s, K, K_len); |
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} |
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|
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void |
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spritz_aead_crypt (spritz_state *s, const void *I, void *O, size_t len) |
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{ |
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const uint8_t *i = (const uint8_t *)I; |
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uint8_t *o = ( uint8_t *)O; |
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|
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uint8_t x[spritz_N >> 2]; |
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|
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while (len) |
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{ |
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uint_fast8_t j; |
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uint8_t l = len > sizeof (x) ? sizeof (x) : len; |
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len -= l; |
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|
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spritz_squeeze (s, x, l); |
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|
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for (j = 0; j < l; ++j) |
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spritz_absorb_byte (s, *o++ = *i++ ^ x[j]); |
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} |
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} |
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|
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void |
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spritz_prng_init (spritz_state *s, const void *S, size_t S_len) |
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{ |
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spritz_init (s); |
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spritz_absorb (s, S, S_len); |
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} |
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|
