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Diffstat (limited to '')
| -rw-r--r-- | contrib/libottery/chacha_merged.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/contrib/libottery/chacha_merged.c b/contrib/libottery/chacha_merged.c new file mode 100644 index 0000000..c31a8bb --- /dev/null +++ b/contrib/libottery/chacha_merged.c @@ -0,0 +1,218 @@ +/* + * This code is based on Dan Bernstein's pure C "merged" 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 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-merged.c version 20080118 +D. J. Bernstein +Public domain. +*/ +#include <string.h> +#include "ottery-internal.h" +#define u8 uint8_t +#define u32 uint32_t +#include "chacha_merged_ecrypt.h" + +#define ROTATE(v,c) (ROTL32(v,c)) +#define XOR(v,w) ((v) ^ (w)) +#define PLUS(v,w) (U32V((v) + (w))) +#define PLUSONE(v) (PLUS((v),1)) + +#define QUARTERROUND(a,b,c,d) \ + a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \ + a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \ + c = PLUS(c,d); b = ROTATE(XOR(b,c), 7); + +static const char sigma[16] = "expand 32-byte k"; + +static void ECRYPT_keysetup(ECRYPT_ctx *x,const u8 *k,u32 ivbits) +{ + const char *constants; + (void)ivbits; + + x->input[4] = U8TO32_LITTLE(k + 0); + x->input[5] = U8TO32_LITTLE(k + 4); + x->input[6] = U8TO32_LITTLE(k + 8); + x->input[7] = U8TO32_LITTLE(k + 12); + k += 16; + constants = sigma; + x->input[8] = U8TO32_LITTLE(k + 0); + x->input[9] = U8TO32_LITTLE(k + 4); + x->input[10] = U8TO32_LITTLE(k + 8); + x->input[11] = U8TO32_LITTLE(k + 12); + x->input[0] = U8TO32_LITTLE(constants + 0); + x->input[1] = U8TO32_LITTLE(constants + 4); + x->input[2] = U8TO32_LITTLE(constants + 8); + x->input[3] = U8TO32_LITTLE(constants + 12); +} + +static void ECRYPT_ivsetup(ECRYPT_ctx *x,const u8 *iv) +{ + x->input[12] = 0; + x->input[13] = 0; + x->input[14] = U8TO32_LITTLE(iv + 0); + x->input[15] = U8TO32_LITTLE(iv + 4); +} + +#define IDX_STEP 16 +#define OUTPUT_LEN (IDX_STEP * 64) + +static inline void chacha_merged_getblocks(const int chacha_rounds, ECRYPT_ctx *x,u8 *c) __attribute__((always_inline)); + +/** Generate OUTPUT_LEN bytes of output using the key, nonce, and counter in x, + * and store them in c. + */ +static void chacha_merged_getblocks(const int chacha_rounds, ECRYPT_ctx *x,u8 *c) +{ + u32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; + u32 j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; + unsigned i, block; + + j0 = x->input[0]; + j1 = x->input[1]; + j2 = x->input[2]; + j3 = x->input[3]; + j4 = x->input[4]; + j5 = x->input[5]; + j6 = x->input[6]; + j7 = x->input[7]; + j8 = x->input[8]; + j9 = x->input[9]; + j10 = x->input[10]; + j11 = x->input[11]; + j12 = x->input[12]; + j13 = x->input[13]; + j14 = x->input[14]; + j15 = x->input[15]; + + for (block = 0; block < IDX_STEP; ++block) { + x0 = j0; + x1 = j1; + x2 = j2; + x3 = j3; + x4 = j4; + x5 = j5; + x6 = j6; + x7 = j7; + x8 = j8; + x9 = j9; + x10 = j10; + x11 = j11; + x12 = j12; + x13 = j13; + x14 = j14; + x15 = j15; + for (i = chacha_rounds;i > 0;i -= 2) { + QUARTERROUND( x0, x4, x8,x12) + QUARTERROUND( x1, x5, x9,x13) + QUARTERROUND( x2, x6,x10,x14) + QUARTERROUND( x3, x7,x11,x15) + QUARTERROUND( x0, x5,x10,x15) + QUARTERROUND( x1, x6,x11,x12) + QUARTERROUND( x2, x7, x8,x13) + QUARTERROUND( x3, x4, x9,x14) + } + x0 = PLUS(x0,j0); + x1 = PLUS(x1,j1); + x2 = PLUS(x2,j2); + x3 = PLUS(x3,j3); + x4 = PLUS(x4,j4); + x5 = PLUS(x5,j5); + x6 = PLUS(x6,j6); + x7 = PLUS(x7,j7); + x8 = PLUS(x8,j8); + x9 = PLUS(x9,j9); + x10 = PLUS(x10,j10); + x11 = PLUS(x11,j11); + x12 = PLUS(x12,j12); + x13 = PLUS(x13,j13); + x14 = PLUS(x14,j14); + x15 = PLUS(x15,j15); + + j12 = PLUSONE(j12); + /* Ottery: j13 can never need to be incremented. */ + + U32TO8_LITTLE(c + 0,x0); + U32TO8_LITTLE(c + 4,x1); + U32TO8_LITTLE(c + 8,x2); + U32TO8_LITTLE(c + 12,x3); + U32TO8_LITTLE(c + 16,x4); + U32TO8_LITTLE(c + 20,x5); + U32TO8_LITTLE(c + 24,x6); + + U32TO8_LITTLE(c + 28,x7); + U32TO8_LITTLE(c + 32,x8); + U32TO8_LITTLE(c + 36,x9); + U32TO8_LITTLE(c + 40,x10); + U32TO8_LITTLE(c + 44,x11); + U32TO8_LITTLE(c + 48,x12); + U32TO8_LITTLE(c + 52,x13); + U32TO8_LITTLE(c + 56,x14); + U32TO8_LITTLE(c + 60,x15); + + c += 64; + } +} + +#define STATE_LEN (sizeof(ECRYPT_ctx)) +#define STATE_BYTES 40 + +static void +chacha_merged_state_setup(void *state_, const uint8_t *bytes) +{ + ECRYPT_ctx *x = state_; + ECRYPT_keysetup(x, bytes, 0); + ECRYPT_ivsetup(x, bytes+32); +} + +static void +chacha8_merged_generate(void *state_, uint8_t *output, uint32_t idx) +{ + ECRYPT_ctx *x = state_; + x->input[12] = idx * IDX_STEP; + chacha_merged_getblocks(8, x, output); +} + +static void +chacha12_merged_generate(void *state_, uint8_t *output, uint32_t idx) +{ + ECRYPT_ctx *x = state_; + x->input[12] = idx * IDX_STEP; + chacha_merged_getblocks(12, x, output); +} + +static void +chacha20_merged_generate(void *state_, uint8_t *output, uint32_t idx) +{ + ECRYPT_ctx *x = state_; + x->input[12] = idx * IDX_STEP; + chacha_merged_getblocks(20, x, output); +} + +#define PRF_CHACHA(r) { \ + "CHACHA" #r, \ + "CHACHA" #r "-NOSIMD", \ + "CHACHA" #r "-NOSIMD-DEFAULT", \ + STATE_LEN, \ + STATE_BYTES, \ + OUTPUT_LEN, \ + 0, \ + chacha_merged_state_setup, \ + chacha ## r ## _merged_generate \ +} + +const struct ottery_prf ottery_prf_chacha8_merged_ = PRF_CHACHA(8); +const struct ottery_prf ottery_prf_chacha12_merged_ = PRF_CHACHA(12); +const struct ottery_prf ottery_prf_chacha20_merged_ = PRF_CHACHA(20); + |