326 lines
8.1 KiB
C
Executable File
326 lines
8.1 KiB
C
Executable File
/* $OpenBSD: chacha-merged.c,v 1.9 2019/01/22 00:59:21 dlg Exp $ */
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/*
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chacha-merged.c version 20080118
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D. J. Bernstein
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Public domain.
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*/
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#include <sys/types.h>
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#include <stdint.h>
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#define CHACHA_MINKEYLEN 16
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#define CHACHA_NONCELEN 8
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#define CHACHA_CTRLEN 8
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#define CHACHA_STATELEN (CHACHA_NONCELEN+CHACHA_CTRLEN)
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#define CHACHA_BLOCKLEN 64
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struct chacha_ctx {
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u_int input[16];
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uint8_t ks[CHACHA_BLOCKLEN];
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uint8_t unused;
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};
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static inline void chacha_keysetup(struct chacha_ctx *x, const u_char *k,
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u_int kbits)
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__attribute__((__bounded__(__minbytes__, 2, CHACHA_MINKEYLEN)));
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static inline void chacha_ivsetup(struct chacha_ctx *x, const u_char *iv,
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const u_char *ctr)
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__attribute__((__bounded__(__minbytes__, 2, CHACHA_NONCELEN)))
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__attribute__((__bounded__(__minbytes__, 3, CHACHA_CTRLEN)));
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static inline void chacha_encrypt_bytes(struct chacha_ctx *x, const u_char *m,
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u_char *c, u_int bytes)
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__attribute__((__bounded__(__buffer__, 2, 4)))
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__attribute__((__bounded__(__buffer__, 3, 4)));
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typedef unsigned char u8;
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typedef unsigned int u32;
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typedef struct chacha_ctx chacha_ctx;
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#define U8C(v) (v##U)
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#define U32C(v) (v##U)
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#define U8V(v) ((u8)(v) & U8C(0xFF))
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#define U32V(v) ((u32)(v) & U32C(0xFFFFFFFF))
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#define ROTL32(v, n) \
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(U32V((v) << (n)) | ((v) >> (32 - (n))))
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#define U8TO32_LITTLE(p) \
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(((u32)((p)[0])) | \
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((u32)((p)[1]) << 8) | \
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((u32)((p)[2]) << 16) | \
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((u32)((p)[3]) << 24))
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#define U32TO8_LITTLE(p, v) \
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do { \
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(p)[0] = U8V((v)); \
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(p)[1] = U8V((v) >> 8); \
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(p)[2] = U8V((v) >> 16); \
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(p)[3] = U8V((v) >> 24); \
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} while (0)
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#define ROTATE(v,c) (ROTL32(v,c))
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#define XOR(v,w) ((v) ^ (w))
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#define PLUS(v,w) (U32V((v) + (w)))
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#define PLUSONE(v) (PLUS((v),1))
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#define QUARTERROUND(a,b,c,d) \
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a = PLUS(a,b); d = ROTATE(XOR(d,a),16); \
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c = PLUS(c,d); b = ROTATE(XOR(b,c),12); \
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a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \
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c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);
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/* Initialise with "expand 32-byte k". */
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static const char sigma[16] = {
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0x65, 0x78, 0x70, 0x61, 0x6e, 0x64, 0x20, 0x33,
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0x32, 0x2d, 0x62, 0x79, 0x74, 0x65, 0x20, 0x6b,
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};
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/* Initialise with "expand 16-byte k". */
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static const char tau[16] = {
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0x65, 0x78, 0x70, 0x61, 0x6e, 0x64, 0x20, 0x31,
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0x36, 0x2d, 0x62, 0x79, 0x74, 0x65, 0x20, 0x6b,
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};
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static inline void
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chacha_keysetup(chacha_ctx *x, const u8 *k, u32 kbits)
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{
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const char *constants;
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x->input[4] = U8TO32_LITTLE(k + 0);
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x->input[5] = U8TO32_LITTLE(k + 4);
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x->input[6] = U8TO32_LITTLE(k + 8);
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x->input[7] = U8TO32_LITTLE(k + 12);
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if (kbits == 256) { /* recommended */
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k += 16;
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constants = sigma;
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} else { /* kbits == 128 */
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constants = tau;
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}
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x->input[8] = U8TO32_LITTLE(k + 0);
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x->input[9] = U8TO32_LITTLE(k + 4);
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x->input[10] = U8TO32_LITTLE(k + 8);
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x->input[11] = U8TO32_LITTLE(k + 12);
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x->input[0] = U8TO32_LITTLE(constants + 0);
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x->input[1] = U8TO32_LITTLE(constants + 4);
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x->input[2] = U8TO32_LITTLE(constants + 8);
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x->input[3] = U8TO32_LITTLE(constants + 12);
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}
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static inline void
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chacha_ivsetup(chacha_ctx *x, const u8 *iv, const u8 *counter)
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{
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x->input[12] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 0);
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x->input[13] = counter == NULL ? 0 : U8TO32_LITTLE(counter + 4);
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x->input[14] = U8TO32_LITTLE(iv + 0);
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x->input[15] = U8TO32_LITTLE(iv + 4);
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}
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static inline void
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chacha_encrypt_bytes(chacha_ctx *x, const u8 *m, u8 *c, u32 bytes)
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{
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u32 x0, x1, x2, x3, x4, x5, x6, x7;
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u32 x8, x9, x10, x11, x12, x13, x14, x15;
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u32 j0, j1, j2, j3, j4, j5, j6, j7;
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u32 j8, j9, j10, j11, j12, j13, j14, j15;
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u8 *ctarget = NULL;
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u8 tmp[64];
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u_int i;
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if (!bytes)
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return;
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j0 = x->input[0];
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j1 = x->input[1];
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j2 = x->input[2];
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j3 = x->input[3];
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j4 = x->input[4];
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j5 = x->input[5];
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j6 = x->input[6];
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j7 = x->input[7];
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j8 = x->input[8];
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j9 = x->input[9];
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j10 = x->input[10];
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j11 = x->input[11];
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j12 = x->input[12];
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j13 = x->input[13];
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j14 = x->input[14];
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j15 = x->input[15];
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for (;;) {
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if (bytes < 64) {
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for (i = 0; i < bytes; ++i)
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tmp[i] = m[i];
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m = tmp;
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ctarget = c;
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c = tmp;
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}
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x0 = j0;
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x1 = j1;
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x2 = j2;
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x3 = j3;
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x4 = j4;
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x5 = j5;
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x6 = j6;
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x7 = j7;
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x8 = j8;
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x9 = j9;
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x10 = j10;
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x11 = j11;
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x12 = j12;
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x13 = j13;
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x14 = j14;
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x15 = j15;
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for (i = 20; i > 0; i -= 2) {
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QUARTERROUND(x0, x4, x8, x12)
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QUARTERROUND(x1, x5, x9, x13)
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QUARTERROUND(x2, x6, x10, x14)
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QUARTERROUND(x3, x7, x11, x15)
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QUARTERROUND(x0, x5, x10, x15)
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QUARTERROUND(x1, x6, x11, x12)
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QUARTERROUND(x2, x7, x8, x13)
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QUARTERROUND(x3, x4, x9, x14)
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}
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x0 = PLUS(x0, j0);
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x1 = PLUS(x1, j1);
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x2 = PLUS(x2, j2);
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x3 = PLUS(x3, j3);
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x4 = PLUS(x4, j4);
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x5 = PLUS(x5, j5);
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x6 = PLUS(x6, j6);
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x7 = PLUS(x7, j7);
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x8 = PLUS(x8, j8);
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x9 = PLUS(x9, j9);
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x10 = PLUS(x10, j10);
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x11 = PLUS(x11, j11);
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x12 = PLUS(x12, j12);
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x13 = PLUS(x13, j13);
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x14 = PLUS(x14, j14);
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x15 = PLUS(x15, j15);
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if (bytes < 64) {
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U32TO8_LITTLE(x->ks + 0, x0);
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U32TO8_LITTLE(x->ks + 4, x1);
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U32TO8_LITTLE(x->ks + 8, x2);
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U32TO8_LITTLE(x->ks + 12, x3);
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U32TO8_LITTLE(x->ks + 16, x4);
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U32TO8_LITTLE(x->ks + 20, x5);
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U32TO8_LITTLE(x->ks + 24, x6);
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U32TO8_LITTLE(x->ks + 28, x7);
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U32TO8_LITTLE(x->ks + 32, x8);
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U32TO8_LITTLE(x->ks + 36, x9);
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U32TO8_LITTLE(x->ks + 40, x10);
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U32TO8_LITTLE(x->ks + 44, x11);
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U32TO8_LITTLE(x->ks + 48, x12);
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U32TO8_LITTLE(x->ks + 52, x13);
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U32TO8_LITTLE(x->ks + 56, x14);
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U32TO8_LITTLE(x->ks + 60, x15);
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}
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x0 = XOR(x0, U8TO32_LITTLE(m + 0));
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x1 = XOR(x1, U8TO32_LITTLE(m + 4));
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x2 = XOR(x2, U8TO32_LITTLE(m + 8));
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x3 = XOR(x3, U8TO32_LITTLE(m + 12));
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x4 = XOR(x4, U8TO32_LITTLE(m + 16));
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x5 = XOR(x5, U8TO32_LITTLE(m + 20));
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x6 = XOR(x6, U8TO32_LITTLE(m + 24));
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x7 = XOR(x7, U8TO32_LITTLE(m + 28));
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x8 = XOR(x8, U8TO32_LITTLE(m + 32));
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x9 = XOR(x9, U8TO32_LITTLE(m + 36));
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x10 = XOR(x10, U8TO32_LITTLE(m + 40));
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x11 = XOR(x11, U8TO32_LITTLE(m + 44));
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x12 = XOR(x12, U8TO32_LITTLE(m + 48));
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x13 = XOR(x13, U8TO32_LITTLE(m + 52));
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x14 = XOR(x14, U8TO32_LITTLE(m + 56));
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x15 = XOR(x15, U8TO32_LITTLE(m + 60));
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j12 = PLUSONE(j12);
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if (!j12) {
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j13 = PLUSONE(j13);
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/*
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* Stopping at 2^70 bytes per nonce is the user's
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* responsibility.
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*/
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}
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U32TO8_LITTLE(c + 0, x0);
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U32TO8_LITTLE(c + 4, x1);
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U32TO8_LITTLE(c + 8, x2);
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U32TO8_LITTLE(c + 12, x3);
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U32TO8_LITTLE(c + 16, x4);
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U32TO8_LITTLE(c + 20, x5);
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U32TO8_LITTLE(c + 24, x6);
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U32TO8_LITTLE(c + 28, x7);
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U32TO8_LITTLE(c + 32, x8);
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U32TO8_LITTLE(c + 36, x9);
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U32TO8_LITTLE(c + 40, x10);
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U32TO8_LITTLE(c + 44, x11);
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U32TO8_LITTLE(c + 48, x12);
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U32TO8_LITTLE(c + 52, x13);
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U32TO8_LITTLE(c + 56, x14);
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U32TO8_LITTLE(c + 60, x15);
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if (bytes <= 64) {
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if (bytes < 64) {
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for (i = 0; i < bytes; ++i)
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ctarget[i] = c[i];
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}
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x->input[12] = j12;
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x->input[13] = j13;
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x->unused = 64 - bytes;
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return;
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}
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bytes -= 64;
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c += 64;
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m += 64;
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}
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}
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void
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CRYPTO_hchacha_20(unsigned char subkey[32], const unsigned char key[32],
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const unsigned char nonce[16])
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{
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uint32_t x[16];
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int i;
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x[0] = U8TO32_LITTLE(sigma + 0);
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x[1] = U8TO32_LITTLE(sigma + 4);
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x[2] = U8TO32_LITTLE(sigma + 8);
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x[3] = U8TO32_LITTLE(sigma + 12);
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x[4] = U8TO32_LITTLE(key + 0);
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x[5] = U8TO32_LITTLE(key + 4);
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x[6] = U8TO32_LITTLE(key + 8);
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x[7] = U8TO32_LITTLE(key + 12);
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x[8] = U8TO32_LITTLE(key + 16);
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x[9] = U8TO32_LITTLE(key + 20);
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x[10] = U8TO32_LITTLE(key + 24);
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x[11] = U8TO32_LITTLE(key + 28);
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x[12] = U8TO32_LITTLE(nonce + 0);
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x[13] = U8TO32_LITTLE(nonce + 4);
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x[14] = U8TO32_LITTLE(nonce + 8);
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x[15] = U8TO32_LITTLE(nonce + 12);
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for (i = 20; i > 0; i -= 2) {
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QUARTERROUND(x[0], x[4], x[8], x[12])
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QUARTERROUND(x[1], x[5], x[9], x[13])
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QUARTERROUND(x[2], x[6], x[10], x[14])
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QUARTERROUND(x[3], x[7], x[11], x[15])
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QUARTERROUND(x[0], x[5], x[10], x[15])
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QUARTERROUND(x[1], x[6], x[11], x[12])
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QUARTERROUND(x[2], x[7], x[8], x[13])
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QUARTERROUND(x[3], x[4], x[9], x[14])
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}
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U32TO8_LITTLE(subkey + 0, x[0]);
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U32TO8_LITTLE(subkey + 4, x[1]);
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U32TO8_LITTLE(subkey + 8, x[2]);
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U32TO8_LITTLE(subkey + 12, x[3]);
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U32TO8_LITTLE(subkey + 16, x[12]);
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U32TO8_LITTLE(subkey + 20, x[13]);
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U32TO8_LITTLE(subkey + 24, x[14]);
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U32TO8_LITTLE(subkey + 28, x[15]);
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}
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