progs/perftest.c: Use from Glibc syscall numbers.

[catacomb] / symm / sha3.c

/* -*-c-*-
 *
 * The SHA3 algorithm family
 *
 * (c) 2017 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <assert.h>
#include <stdarg.h>
#include <string.h>

#include "hash.h"
#include "ghash-def.h"
#include "sha3.h"

/*----- General utilities -------------------------------------------------*/

static void absorb(sha3_ctx *ctx, const octet *p, unsigned r)
{
  kludge64 t[25];
  unsigned i;

/* memdump("absorb", p, 8*r, 0); */
  for (i = 0; i < r; i++) { LOAD64_L_(t[i], p); p += 8; }
  keccak1600_mix(&ctx->s, t, r);
}

static void step(sha3_ctx *ctx) { keccak1600_p(&ctx->s, &ctx->s, 24); }

static void pad(sha3_ctx *ctx, unsigned lo, unsigned hi)
{
  size_t spare = ctx->r - ctx->n;

  if (spare == 1)
    ctx->buf[ctx->n] = lo | hi;
  else {
    ctx->buf[ctx->n] = lo;
    ctx->buf[ctx->r - 1] = hi;
    memset(ctx->buf + ctx->n + 1, 0, spare - 2);
  }
  absorb(ctx, ctx->buf, ctx->r/8);
}

static void squeeze(sha3_ctx *ctx, octet *p, unsigned r)
{
  kludge64 t[25];
  unsigned i;

  keccak1600_extract(&ctx->s, t, r);
  for (i = 0; i < r; i++) { STORE64_L_(p, t[i]); p += 8; }
/* memdump("squeeze", p - 8*r, 8*r, 0); */
}

enum {
  OP_CSHAKE = 0x04,
  OP_SHA3 = 0x06,
  OP_SHAKE = 0x1f
};

enum { ST_ABSORB, ST_SQUEEZE, ST_DEAD };

/*----- The SHA3 algorithms -----------------------------------------------*/

/* --- @sha3_{224,256,384,512}_init@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context block to initialize
 *
 * Returns:     ---
 *
 * Use:         Initializes a SHA3 hashing context for use.
 */

static void init_sha3(sha3_ctx *ctx, unsigned w)
{
  keccak1600_init(&ctx->s);
  ctx->w = w/8; ctx->r = (1600 - 2*w)/8; ctx->n = 0;
}

void sha3_224_init(sha3_ctx *ctx) { init_sha3(ctx, 224); }
void sha3_256_init(sha3_ctx *ctx) { init_sha3(ctx, 256); }
void sha3_384_init(sha3_ctx *ctx) { init_sha3(ctx, 384); }
void sha3_512_init(sha3_ctx *ctx) { init_sha3(ctx, 512); }

/* --- @sha3_hash@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context bock
 *              @const void *p@ = pointer to data to hash
 *              @size_t sz@ = size of buffer to hash
 *
 * Returns:     ---
 *
 * Use:         Hashes a buffer of data.  The buffer may be of any size and
 *              alignment.
 */

void sha3_hash(sha3_ctx *ctx, const void *p, size_t sz)
{
  const octet *q = p;
  size_t spare = ctx->r - ctx->n;

  if (sz < spare) {
    memcpy(ctx->buf + ctx->n, q, sz);
    ctx->n += sz;
    return;
  }
  if (ctx->n) {
    memcpy(ctx->buf + ctx->n, q, spare);
    absorb(ctx, ctx->buf, ctx->r/8);
    step(ctx);
    q += spare; sz -= spare;
  }
  while (sz >= ctx->r) {
    absorb(ctx, q, ctx->r/8);
    step(ctx);
    q += ctx->r; sz -= ctx->r;
  }
  if (sz) memcpy(ctx->buf, q, sz);
  ctx->n = sz;
}

/* --- @sha3_done@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context block
 *              @void *hash@ = pointer to output buffer
 *
 * Returns:     ---
 *
 * Use:         Returns the hash of the data read so far.
 */

void sha3_done(sha3_ctx *ctx, void *hash)
{
  pad(ctx, OP_SHA3, 0x80);
  step(ctx);

  if (ctx->w%8 == 0)
    squeeze(ctx, hash, ctx->w/8);
  else {
    squeeze(ctx, ctx->buf, (ctx->w + 7)/8);
    memcpy(hash, ctx->buf, ctx->w);
  }
}

/* --- @sha3_{224,256,384,512}_set@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context block
 *              @const void *buf@ = pointer to state buffer
 *              @unsigned long count@ = current count of bytes processed
 *
 * Returns:     ---
 *
 * Use:         Initializes a context block from a given state.  This is
 *              something of a kludge for the benefit of HMAC, but there are
 *              better ways to use SHA3 as a MAC.
 *
 *              Furthermore, the @count@ argument is expected to be zero or
 *              be the output of @sha3_state@ below.  Doing anything else
 *              won't work properly.
 */

static void set(sha3_ctx *ctx, const void *buf,
                unsigned long count, unsigned w)
{
  if (count)
    memcpy(ctx, buf, sizeof(*ctx));
  else {
    static const char *prefix = "Catacomb SHA3 NMAC kludge";
    init_sha3(ctx, w);
    sha3_hash(ctx, prefix, sizeof(prefix));
    sha3_hash(ctx, buf, SHA3_STATESZ);
  }
}

void sha3_224_set(sha3_ctx *ctx, const void *buf, unsigned long count)
  { set(ctx, buf, count, 224); }
void sha3_256_set(sha3_ctx *ctx, const void *buf, unsigned long count)
  { set(ctx, buf, count, 256); }
void sha3_384_set(sha3_ctx *ctx, const void *buf, unsigned long count)
  { set(ctx, buf, count, 384); }
void sha3_512_set(sha3_ctx *ctx, const void *buf, unsigned long count)
  { set(ctx, buf, count, 512); }

/* --- @sha3_state@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context block
 *              @void *state@ = pointer to buffer for current state
 *
 * Returns:     A value which is meaningful to @sha3_..._set@.
 *
 * Use:         Returns the current state of the hash function such that it
 *              can be passed to @sha3_..._set@.
 */

unsigned long sha3_state(sha3_ctx *ctx, void *state)
  { memcpy(state, ctx, sizeof(*ctx)); return (1); }

#define HASHES(_)                                                       \
  _(SHA3_224, sha3_224, "sha3-224")                                     \
  _(SHA3_256, sha3_256, "sha3-256")                                     \
  _(SHA3_384, sha3_384, "sha3-384")                                     \
  _(SHA3_512, sha3_512, "sha3-512")
HASHES(GHASH_DEFX)

/*----- The cSHAKE XOF algorithm ------------------------------------------*/

static void leftenc_sz(shake_ctx *ctx, size_t n)
{
  kludge64 t;
  octet b[9];
  unsigned i;

  SET64(t, ((n&~(size_t)MASK32) >> 16) >> 16, n&MASK32);
  STORE64_B_(b + 1, t);
  for (i = 1; i < 8 && !b[i]; i++);
  i--; b[i] = 8 - i;
  shake_hash(ctx, b + i, 9 - i);
}

static void rightenc_sz(shake_ctx *ctx, size_t n)
{
  kludge64 t;
  octet b[9];
  unsigned i;

  SET64(t, ((n&~(size_t)MASK32) >> 16) >> 16, n&MASK32);
  STORE64_B_(b, t);
  for (i = 0; i < 7 && !b[i]; i++);
  b[8] = 8 - i;
  shake_hash(ctx, b + i, 9 - i);
}

static void stringenc(shake_ctx *ctx, const void *p, size_t sz)
  { leftenc_sz(ctx, 8*sz); if (sz) shake_hash(ctx, p, sz); }

static void bytepad_before(shake_ctx *ctx)
  { leftenc_sz(ctx, ctx->h.r); }

static void bytepad_after(shake_ctx *ctx)
{
  unsigned pad;

  if (ctx->h.n%8) {
    pad = 8 - ctx->h.n%8;
    memset(ctx->h.buf + ctx->h.n, 0, pad);
    ctx->h.n += pad;
  }
  if (ctx->h.n) {
    absorb(&ctx->h, ctx->h.buf, ctx->h.n/8);
    step(&ctx->h); ctx->h.n = 0;
  }
}

const octet
  shake128_keysz[] = { KSZ_ANY, SHAKE128_KEYSZ },
  shake256_keysz[] = { KSZ_ANY, SHAKE256_KEYSZ };

/* --- @cshake{128,256}_init@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = pointer to context to initialize
 *              @const void *func@ = NIST-allocated function name
 *              @size_t fsz@ = length of function name
 *              @const void *perso@ = user personalization string
 *              @size_t psz@ = length of personalization string
 *
 * Returns:     ---
 *
 * Use:         Initializes a cSHAKE context.  The context is initially in
 *              the `absorbing' state: feed it data with @shake_hash@.
 */

static void init_shake(shake_ctx *ctx, unsigned c0,
                       const void *func, size_t fsz,
                       const void *perso, size_t psz)
{
  keccak1600_init(&ctx->h.s); ctx->st = ST_ABSORB;
  ctx->h.r = (1600 - 2*c0)/8; ctx->h.w = 0; ctx->h.n = 0;
  if (!fsz && !psz)
    ctx->op = OP_SHAKE;
  else {
    bytepad_before(ctx);
    stringenc(ctx, func, fsz);
    stringenc(ctx, perso, psz);
    bytepad_after(ctx);
    ctx->op = OP_CSHAKE;
  }
}

void cshake128_init(shake_ctx *ctx,
                    const void *func, size_t fsz,
                    const void *perso, size_t psz)
  { init_shake(ctx, 128, func, fsz, perso, psz); }

void cshake256_init(shake_ctx *ctx,
                    const void *func, size_t fsz,
                    const void *perso, size_t psz)
  { init_shake(ctx, 256, func, fsz, perso, psz); }

/* --- @shake{128,256}_init@ --- *
 *
 * Arguments:   @sha3_ctx *ctx@ = pointer to context to initialize
 *
 * Returns:     ---
 *
 * Use:         Initializes a SHAKE context.  The context is initially in
 *              the `absorbing' state: feed it data with @shake_hash@.
 */

void shake128_init(shake_ctx *ctx) { init_shake(ctx, 128, 0, 0, 0, 0); }
void shake256_init(shake_ctx *ctx) { init_shake(ctx, 256, 0, 0, 0, 0); }

/* --- @shake_hash@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = context to update
 *              @const void *p@ = input buffer
 *              @size_t sz@ = size of input
 *
 * Returns:     ---
 *
 * Use:         Feeds input data into a SHAKE context.  The context must be
 *              in `absorbing' state.
 */

void shake_hash(shake_ctx *ctx, const void *p, size_t sz)
  { assert(ctx->st == ST_ABSORB); sha3_hash(&ctx->h, p, sz); }

/* --- @shake_xof@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = context to update
 *
 * Returns:     ---
 *
 * Use:         Switches the context into `squeezing' state.  Use @shake_get@
 *              or @shake_mask@ to extract data.
 */

void shake_xof(shake_ctx *ctx)
{
  assert(ctx->st == ST_ABSORB);
  pad(&ctx->h, ctx->op, 0x80);
  ctx->st = ST_SQUEEZE;
  ctx->h.n = ctx->h.r;
}

/* --- @shake_get@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = context to update
 *              @void *p@ = output buffer
 *              @size_t sz@ = size of output
 *
 * Returns:     ---
 *
 * Use:         Extracts output from a SHAKE context.  The context must be
 *              in `squeezing' state.
 */

void shake_get(shake_ctx *ctx, void *p, size_t sz)
{
  octet *q = p;
  size_t left = ctx->h.r - ctx->h.n;

  assert(ctx->st == ST_SQUEEZE);
  if (left >= sz) {
    memcpy(q, ctx->h.buf + ctx->h.n, sz);
    ctx->h.n += sz;
    return;
  }
  if (left) {
    memcpy(q, ctx->h.buf + ctx->h.n, left);
    q += left; sz -= left;
  }
  while (sz >= ctx->h.r) {
    step(&ctx->h);
    squeeze(&ctx->h, q, ctx->h.r/8);
    q += ctx->h.r; sz -= ctx->h.r;
  }
  if (!sz)
    ctx->h.n = ctx->h.r;
  else {
    step(&ctx->h);
    squeeze(&ctx->h, ctx->h.buf, ctx->h.r/8);
    memcpy(q, ctx->h.buf, sz);
    ctx->h.n = sz;
  }
}

/* --- @shake_mask@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = context to update
 *              @const void *src@ = pointer to source data, or null
 *              @void *dest@ = output buffer
 *              @size_t sz@ = size of output
 *
 * Returns:     ---
 *
 * Use:         Mask the @src@ data by XORing it with output from the SHAKE
 *              context, writing the result to @dest@.  The @src@ and @dest
 *              buffers may be equal but must not otherwise overlap.  The
 *              context must be in `squeezing' state.
 */

void shake_mask(shake_ctx *ctx, const void *src, void *dest, size_t sz)
{
  const octet *p = src, *pp, *l;
  octet *q = dest;
  size_t left = ctx->h.r - ctx->h.n;

  if (!src) { shake_get(ctx, dest, sz); return; }

  assert(ctx->st == ST_SQUEEZE);
  if (left >= sz) {
    pp = ctx->h.buf + ctx->h.n; l = q + sz;
    while (q < l) *q++ = *p++ ^ *pp++;
    ctx->h.n += sz;
    return;
  }
  if (left) {
    pp = ctx->h.buf + ctx->h.n; l = q + left;
    while (q < l) *q++ = *p++ ^ *pp++;
    sz -= left;
  }
  while (sz >= ctx->h.r) {
    step(&ctx->h);
    squeeze(&ctx->h, ctx->h.buf, ctx->h.r/8);
    pp = ctx->h.buf; l = pp + ctx->h.r;
    while (pp < l) *q++ = *p++ ^ *pp++;
    sz -= ctx->h.r;
  }
  if (!sz)
    ctx->h.n = ctx->h.r;
  else {
    step(&ctx->h);
    squeeze(&ctx->h, ctx->h.buf, ctx->h.r/8);
    pp = ctx->h.buf; l = q + sz;
    while (q < l) *q++ = *p++ ^ *pp++;
    ctx->h.n = sz;
  }
}

/* --- @shake_done@ --- *
 *
 * Arguments:   @shake_ctx *ctx@ = context to update
 *              @void *h@ = where to write the hash
 *              @size_t hsz@ = size of the hash to make
 *
 * Returns:     ---
 *
 * Use:         Switches the context into `squeezing' state.  Use @shake_get@
 *              or @shake_mask@ to extract data.
 */

void shake_done(shake_ctx *ctx, void *h, size_t hsz)
  { shake_xof(ctx); shake_get(ctx, h, hsz); ctx->st = ST_DEAD; }

/* --- Hash interface --- */

typedef struct shake_ghctx {
  ghash h;
  shake_ctx c;
  octet hb[SHAKE256_HASHSZ];
} shake_ghctx;

static const ghash_ops shake128_ghops, shake256_ghops;

static void shake_ghhash(ghash *h, const void *p, size_t sz)
  { shake_ghctx *cc = (shake_ghctx *)h; shake_hash(&cc->c, p, sz); }

static octet *shake_ghdone(ghash *h, void *buf)
{
  shake_ghctx *cc = (shake_ghctx *)h;
  if (!buf) buf = cc->hb;
  shake_done(&cc->c, buf, h->ops->c->hashsz);
  return (buf);
}

static void shake_ghdestroy(ghash *h)
  { shake_ghctx *cc = (shake_ghctx *)h; BURN(cc); S_DESTROY(cc); }

static ghash *shake_ghcopy(ghash *h)
{
  shake_ghctx *cc = (shake_ghctx *)h;
  shake_ghctx *hc = S_CREATE(shake_ghctx);
  *hc = *cc;
  return (&hc->h);
}

static ghash *shake128_ghinit(void)
{
  shake_ghctx *cc = S_CREATE(shake_ghctx);
  cc->h.ops = &shake128_ghops;
  shake128_init(&cc->c);
  return (&cc->h);
}

static ghash *shake256_ghinit(void)
{
  shake_ghctx *cc = S_CREATE(shake_ghctx);
  cc->h.ops = &shake256_ghops;
  shake256_init(&cc->c);
  return (&cc->h);
}

const gchash
  shake128 = { "shake128", SHAKE128_HASHSZ, shake128_ghinit, 168 },
  shake256 = { "shake256", SHAKE256_HASHSZ, shake256_ghinit, 136 };

static const ghash_ops
  shake128_ghops = { &shake128, shake_ghhash, shake_ghdone,
                     shake_ghdestroy, shake_ghcopy },
  shake256_ghops = { &shake256, shake_ghhash, shake_ghdone,
                     shake_ghdestroy, shake_ghcopy };

/* --- Cipher interface --- */

typedef struct shake_gcctx {
  gcipher gc;
  shake_ctx c;
} shake_gcctx;

static const gcipher_ops shake128_gcops, shake256_gcops;

static void shake_gcencdec(gcipher *c, const void *s, void *d, size_t sz)
  { shake_gcctx *cc = (shake_gcctx *)c; shake_mask(&cc->c, s, d, sz); }

static void shake_gcdestroy(gcipher *c)
  { shake_gcctx *cc = (shake_gcctx *)c; BURN(*cc); S_DESTROY(cc); }

static const gcipher_ops
  shake128_gcops = { &shake128_xof, shake_gcencdec, shake_gcencdec,
                     shake_gcdestroy, 0, 0 },
  shake256_gcops = { &shake256_xof, shake_gcencdec, shake_gcencdec,
                     shake_gcdestroy, 0, 0 };

static gcipher *shake128_gcinit(const void *k, size_t sz)
{
  shake_gcctx *cc = S_CREATE(shake_gcctx);
  cc->gc.ops = &shake128_gcops;
  shake128_init(&cc->c); shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gc);
}

static gcipher *shake256_gcinit(const void *k, size_t sz)
{
  shake_gcctx *cc = S_CREATE(shake_gcctx);
  cc->gc.ops = &shake256_gcops;
  shake256_init(&cc->c); shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gc);
}

const gccipher
  shake128_xof = { "shake128-xof", shake128_keysz, 0, shake128_gcinit },
  shake256_xof = { "shake256-xof", shake256_keysz, 0, shake256_gcinit };

/* --- Random generator interface --- */

typedef struct shake_grctx {
  grand gr;
  shake_ctx c;
} shake_grctx;

static int shake_grmisc(grand *r, unsigned op, ...)
{
  int rc = 0;
  switch (op) {
    case GRAND_CHECK: rc = 0; break;
    default: GRAND_BADOP; break;
  }
  return (rc);
}

static void shake_grdestroy(grand *r)
  { shake_grctx *cc = (shake_grctx *)r; BURN(cc); S_DESTROY(cc); }

static octet shake_grbyte(grand *r)
{
  shake_grctx *cc = (shake_grctx *)r;
  octet o;
  shake_get(&cc->c, &o, 1);
  return (o);
}

static uint32 shake_grword(grand *r)
{
  shake_grctx *cc = (shake_grctx *)r;
  octet b[4];
  shake_get(&cc->c, &b, 4);
  return (LOAD32(b));
}

static void shake_grfill(grand *r, void *p, size_t sz)
  { shake_grctx *cc = (shake_grctx *)r; shake_get(&cc->c, p, sz); }

static const grand_ops
  shake128_grops = { "shake128", GRAND_CRYPTO, 0,
                     shake_grmisc, shake_grdestroy, shake_grword,
                     shake_grbyte, shake_grword, grand_defaultrange,
                     shake_grfill },
  shake256_grops = { "shake256", GRAND_CRYPTO, 0,
                     shake_grmisc, shake_grdestroy, shake_grword,
                     shake_grbyte, shake_grword, grand_defaultrange,
                     shake_grfill },
  cshake128_grops = { "cshake128", GRAND_CRYPTO, 0,
                      shake_grmisc, shake_grdestroy, shake_grword,
                      shake_grbyte, shake_grword, grand_defaultrange,
                      shake_grfill },
  cshake256_grops = { "cshake256", GRAND_CRYPTO, 0,
                      shake_grmisc, shake_grdestroy, shake_grword,
                      shake_grbyte, shake_grword, grand_defaultrange,
                      shake_grfill };

/* --- @shake{128,256}_rand@ --- *
 *
 * Arguments:   @const void *k@ = pointer to seed material
 *              @size_t sz@ = size of the seed
 *
 * Returns:     A pseudorandom generator with the given seed.
 */

grand *shake128_rand(const void *k, size_t sz)
{
  shake_grctx *cc = S_CREATE(shake_grctx);
  cc->gr.ops = &shake128_grops;
  shake128_init(&cc->c); shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gr);
}

grand *shake256_rand(const void *k, size_t sz)
{
  shake_grctx *cc = S_CREATE(shake_grctx);
  cc->gr.ops = &shake256_grops;
  shake256_init(&cc->c); shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gr);
}

/* --- @cshake{128,256}_rand@ --- *
 *
 * Arguments:   @const void *func@ = function name
 *              @size_t fsz@ = length of function name
 *              @const void *perso@ = personalization string
 *              @size_t psz@ = length of personalization string
 *              @const void *k@ = pointer to seed material
 *              @size_t sz@ = size of the seed
 *
 * Returns:     A pseudorandom generator with the given seed.
 */

grand *cshake128_rand(const void *func, size_t fsz,
                      const void *perso, size_t psz,
                      const void *k, size_t sz)
{
  shake_grctx *cc = S_CREATE(shake_grctx);
  cc->gr.ops = &cshake128_grops;
  cshake128_init(&cc->c, func, fsz, perso, psz);
  shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gr);
}

grand *cshake256_rand(const void *func, size_t fsz,
                      const void *perso, size_t psz,
                      const void *k, size_t sz)
{
  shake_grctx *cc = S_CREATE(shake_grctx);
  cc->gr.ops = &cshake256_grops;
  cshake256_init(&cc->c, func, fsz, perso, psz);
  shake_hash(&cc->c, k, sz); shake_xof(&cc->c);
  return (&cc->gr);
}

/*----- The KMAC variable-length PRF --------------------------------------*/

typedef shake_ctx kmac_ctx;

/* --- @kmac{128,256}_init@ --- *
 *
 * Arguments:   @kmac_ctx *ctx@ = pointer to context to fill in
 *              @const char *perso@ = personalization string, or null
 *              @size_t psz@ = length of personalization string
 *              @const void *k@ = pointer to key material
 *              @size_t sz@ = size of key material
 *
 * Returns:     ---
 *
 * Use:         Sets up a KMAC context.  Use @kmac_hash@ to feed in the input
 *              message.
 */

static void init_kmac(kmac_ctx *ctx,
                      unsigned c0, const void *perso, size_t psz,
                      const void *k, size_t sz)
{
  init_shake(ctx, c0, "KMAC", 4, perso, psz);
  bytepad_before(ctx); stringenc(ctx, k, sz); bytepad_after(ctx);
}

void kmac128_init(kmac_ctx *ctx, const void *perso, size_t psz,
                  const void *k, size_t sz)
  { init_kmac(ctx, 128, perso, psz, k, sz); }

void kmac256_init(kmac_ctx *ctx, const void *perso, size_t psz,
                  const void *k, size_t sz)
  { init_kmac(ctx, 256, perso, psz, k, sz); }

/* --- @kmac_xof@ --- *
 *
 * Arguments:   @kmac_ctx *ctx@ = pointer to context
 *
 * Returns:     ---
 *
 * Use:         Marks the end of the message to be processed.  The output can
 *              be read using @kmac_get@.
 */

void kmac_xof(kmac_ctx *ctx)
  { rightenc_sz(ctx, 0); shake_xof(ctx); }

/* --- @kmac_done@ --- *
 *
 * Arguments:   @kmac_ctx *ctx@ = pointer to context
 *              @void *h@ = where to put the tag
 *              @size_t hsz@ = size of tag to produce
 *
 * Returns:     ---
 *
 * Use:         Marks the end of the message to be processed and returns a
 *              tag.  Note that the tag value is dependent on the output
 *              size.
 */

void kmac_done(kmac_ctx *ctx, void *h, size_t hsz)
  { rightenc_sz(ctx, 8*hsz); shake_done(ctx, h, hsz); }

/* --- MAC interface --- */

typedef struct kmac_ghctx {
  ghash h;
  kmac_ctx c;
  octet hb[KMAC256_TAGSZ];
} kmac_ghctx;

typedef struct kmac_gmctx {
  gmac m;
  kmac_ctx c;
  const ghash_ops *hops;
} kmac_gmctx;

static const ghash_ops kmac128_ghops, kmac256_ghops;
static const gmac_ops kmac128_gmops, kmac256_gmops;

static void kmac_ghhash(ghash *h, const void *p, size_t sz)
  { kmac_ghctx *cc = (kmac_ghctx *)h; kmac_hash(&cc->c, p, sz); }

static octet *kmac_ghdone(ghash *h, void *buf)
{
  kmac_ghctx *cc = (kmac_ghctx *)h;
  if (!buf) buf = cc->hb;
  kmac_done(&cc->c, buf, cc->h.ops->c->hashsz);
  return (buf);
}

static void kmac_ghdestroy(ghash *h)
  { kmac_ghctx *cc = (kmac_ghctx *)h; BURN(cc); S_DESTROY(cc); }

static ghash *kmac_ghcopy(ghash *h)
{
  kmac_ghctx *cc = (kmac_ghctx *)h;
  kmac_ghctx *hc = S_CREATE(kmac_ghctx);
  *hc = *cc;
  return (&hc->h);
}

static ghash *kmac_ghinit(void)
  { assert(((void)"Attempt to instantiate an unkeyed MAC", 0)); return (0); }

static ghash *kmac_gminit(gmac *m)
{
  kmac_gmctx *cc = (kmac_gmctx *)m;
  kmac_ghctx *hc = S_CREATE(kmac_ghctx);
  hc->h.ops = cc->hops;
  hc->c = cc->c;
  return (&hc->h);
}

static void kmac_gmdestroy(gmac *m)
  { kmac_gmctx *cc = (kmac_gmctx *)m; BURN(cc); S_DESTROY(cc); }

static gmac *kmac128_gmkey(const void *k, size_t sz)
{
  kmac_gmctx *cc = S_CREATE(kmac_gmctx);
  cc->m.ops = &kmac128_gmops; cc->hops = &kmac128_ghops;
  kmac128_init(&cc->c, 0, 0, k, sz);
  return (&cc->m);
}

static gmac *kmac256_gmkey(const void *k, size_t sz)
{
  kmac_gmctx *cc = S_CREATE(kmac_gmctx);
  cc->m.ops = &kmac256_gmops; cc->hops = &kmac256_ghops;
  kmac256_init(&cc->c, 0, 0, k, sz);
  return (&cc->m);
}

static const gchash
  kmac128_ghcls = { "kmac128", KMAC128_TAGSZ, kmac_ghinit, 168 },
  kmac256_ghcls = { "kmac256", KMAC256_TAGSZ, kmac_ghinit, 136 };

const gcmac
  kmac128 = { "kmac128", KMAC128_TAGSZ, kmac128_keysz, kmac128_gmkey },
  kmac256 = { "kmac256", KMAC256_TAGSZ, kmac256_keysz, kmac256_gmkey };

static const ghash_ops
  kmac128_ghops = { &kmac128_ghcls, kmac_ghhash, kmac_ghdone,
                    kmac_ghdestroy, kmac_ghcopy },
  kmac256_ghops = { &kmac256_ghcls, kmac_ghhash, kmac_ghdone,
                    kmac_ghdestroy, kmac_ghcopy };

static const gmac_ops
  kmac128_gmops = { &kmac128, kmac_gminit, kmac_gmdestroy },
  kmac256_gmops = { &kmac256, kmac_gminit, kmac_gmdestroy };

/* --- Random generator XOF interface --- */

typedef struct kmac_grctx {
  grand gr;
  kmac_ctx k, c;
} kmac_grctx;

static int kmac_grmisc(grand *r, unsigned op, ...)
{
  kmac_grctx *cc = (kmac_grctx *)r;
  int rc = 0;
  octet buf[64];
  va_list ap;
  int i;
  uint32 u;
  grand *rr;
  const void *p;
  size_t sz;

  va_start(ap, op);
  switch (op) {
    case GRAND_CHECK:
      op = va_arg(ap, unsigned);
      switch (op) {
        case GRAND_SEEDINT: case GRAND_SEEDUINT32:
        case GRAND_SEEDBLOCK: case GRAND_SEEDRAND:
          rc = 1; break;
        default:
          rc = 0; break;
      }
      break;
    case GRAND_SEEDINT:
      i = va_arg(ap, int); STORE32_L(buf, i); p = buf; sz = 4; goto seed;
    case GRAND_SEEDUINT32:
      u = va_arg(ap, uint32); STORE32_L(buf, u); p = buf; sz = 4; goto seed;
    case GRAND_SEEDRAND:
      rr = va_arg(ap, grand *);
      p = buf; sz = (200 - cc->c.h.r)/2; GR_FILL(rr, buf, sz); goto seed;
    case GRAND_SEEDBLOCK:
      p = va_arg(ap, const void *); sz = va_arg(ap, size_t);
    seed:
      cc->c = cc->k;
      kmac_hash(&cc->c, p, sz);
      kmac_xof(&cc->c);
      break;
    default: GRAND_BADOP; break;
  }
  return (rc);
}

static void kmac_grdestroy(grand *r)
  { kmac_grctx *cc = (kmac_grctx *)r; BURN(cc); S_DESTROY(cc); }

static octet kmac_grbyte(grand *r)
{
  kmac_grctx *cc = (kmac_grctx *)r;
  octet o;
  kmac_get(&cc->c, &o, 1);
  return (o);
}

static uint32 kmac_grword(grand *r)
{
  kmac_grctx *cc = (kmac_grctx *)r;
  octet b[4];
  kmac_get(&cc->c, &b, 4);
  return (LOAD32(b));
}

static void kmac_grfill(grand *r, void *p, size_t sz)
  { kmac_grctx *cc = (kmac_grctx *)r; kmac_get(&cc->c, p, sz); }

static const grand_ops
  kmac128_grops = { "kmac128", GRAND_CRYPTO, 0,
                    kmac_grmisc, kmac_grdestroy, kmac_grword,
                    kmac_grbyte, kmac_grword, grand_defaultrange,
                    kmac_grfill },
  kmac256_grops = { "kmac256", GRAND_CRYPTO, 0,
                    kmac_grmisc, kmac_grdestroy, kmac_grword,
                    kmac_grbyte, kmac_grword, grand_defaultrange,
                    kmac_grfill };

/* --- @kmac{128,256}_rand@ --- *
 *
 * Arguments:   @const void *perso@ = personalization string, or null
 *              @size_t psz@ = length of personalization string
 *              @const void *k@ = pointer to seed material
 *              @size_t sz@ = size of the seed
 *
 * Returns:     A pseudorandom generator with the given key.
 *
 * Use:         The generator processes an empty message by default, but this
 *              can be changed by seeding it.
 */

grand *kmac128_rand(const void *perso, size_t psz, const void *k, size_t sz)
{
  kmac_grctx *cc = S_CREATE(kmac_grctx);
  cc->gr.ops = &kmac128_grops;
  kmac128_init(&cc->k, perso, psz, k, sz);
  cc->c = cc->k; kmac_xof(&cc->c);
  return (&cc->gr);
}

grand *kmac256_rand(const void *perso, size_t psz, const void *k, size_t sz)
{
  kmac_grctx *cc = S_CREATE(kmac_grctx);
  cc->gr.ops = &kmac256_grops;
  kmac256_init(&cc->k, perso, psz, k, sz);
  cc->c = cc->k; kmac_xof(&cc->c);
  return (&cc->gr);
}

/*----- Test rig ----------------------------------------------------------*/

#ifdef TEST_RIG

#include <stdio.h>

#include <mLib/macros.h>
#include <mLib/report.h>
#include <mLib/testrig.h>

HASHES(HASH_VERIFYX)

static int vrf_sha3_mct(void (*initfn)(sha3_ctx *),
                        int n, dstr *in, dstr *out)
{
  sha3_ctx ctx;
  dstr d = DSTR_INIT;
  int ok = 1;
  int i;

  if (in->len != out->len) die(1, "inconsistent lengths");
  dstr_ensure(&d, out->len); d.len = out->len;
  memcpy(d.buf, in->buf, in->len);
  for (i = 0; i < n; i++) {
    initfn(&ctx);
    sha3_hash(&ctx, d.buf, d.len);
    sha3_done(&ctx, d.buf);
  }

  if (MEMCMP(d.buf, !=, out->buf, out->len)) {
    ok = 0;
    printf("\nfail\n\tsteps = %d\n\tinput = ", n);
    type_hex.dump(in, stdout);
    printf("\n\texpected = ");
    type_hex.dump(out, stdout);
    fputs("\n\tcomputed = ", stdout);
    type_hex.dump(&d, stdout);
    putchar('\n');
  }

  dstr_destroy(&d);
  return (ok);
}

#define VRF_MCT(PRE, pre, name)                                         \
  static int vrf_##pre##_mct(dstr *v)                                   \
    { return (vrf_sha3_mct(pre##_init, *(int *)v[0].buf, &v[1], &v[2])); }
HASHES(VRF_MCT)
#undef VRF_MCT

static int vrf_shaky(void (*initfn)(shake_ctx *,
                                    const void *, size_t,
                                    const void *, size_t),
                     dstr *func, dstr *perso,
                     dstr *m, dstr *want)
{
  shake_ctx ctx;
  dstr d = DSTR_INIT;
  int ok = 1;
  int i;
  const int *ip;
  size_t sz;
  octet *p;
  static const int szs[] = { 1, 7, 192, -1, 0 };

  dstr_ensure(&d, want->len); d.len = want->len;
  for (ip = szs; *ip; ip++) {
    initfn(&ctx,
           func ? func->buf : 0, func ? func->len : 0,
           perso ? perso->buf : 0, perso ? perso->len : 0);
    p = (octet *)m->buf; sz = m->len;
    i = (*ip == -1 || *ip > sz) ? sz : *ip;
    while (sz) {
      if (i > sz) i = sz;
      shake_hash(&ctx, p, i);
      p += i; sz -= i;
    }
    shake_xof(&ctx);

    p = (octet *)d.buf; sz = d.len;
    i = (*ip == -1 || *ip > sz) ? sz : *ip;
    while (sz) {
      if (i > sz) i = sz;
      shake_get(&ctx, p, i);
      p += i; sz -= i;
    }

    if (MEMCMP(d.buf, !=, want->buf, want->len)) {
      ok = 0;
      printf("\nfail (get):\n\tstep = %i\n\tinput = ", *ip);
      type_hex.dump(m, stdout);
      if (func) printf("\n\tfunction = `%s'", func->buf);
      if (perso) printf("\n\tperso = `%s'", perso->buf);
      printf("\n\texpected = ");
      type_hex.dump(want, stdout);
      fputs("\n\tcomputed = ", stdout);
      type_hex.dump(&d, stdout);
      putchar('\n');
    }

    initfn(&ctx,
           func ? func->buf : 0, func ? func->len : 0,
           perso ? perso->buf : 0, perso ? perso->len : 0);
    p = (octet *)m->buf; sz = m->len;
    i = (*ip == -1 || *ip > sz) ? sz : *ip;
    while (sz) {
      if (i > sz) i = sz;
      shake_hash(&ctx, p, i);
      p += i; sz -= i;
    }
    shake_xof(&ctx);

    memset(d.buf, 0, d.len);
    p = (octet *)d.buf; sz = d.len;
    i = (*ip == -1 || *ip > sz) ? sz : *ip;
    while (sz) {
      if (i > sz) i = sz;
      shake_mask(&ctx, p, p, i);
      p += i; sz -= i;
    }

    if (MEMCMP(d.buf, !=, want->buf, want->len)) {
      ok = 0;
      printf("\nfail (mask):\n\tstep = %i\n\tinput = ", *ip);
      type_hex.dump(m, stdout);
      if (func) printf("\n\tfunction = `%s'", func->buf);
      if (perso) printf("\n\tperso = `%s'", perso->buf);
      printf("\n\texpected = ");
      type_hex.dump(want, stdout);
      fputs("\n\tcomputed = ", stdout);
      type_hex.dump(&d, stdout);
      putchar('\n');
    }
  }

  dstr_destroy(&d);
  return (ok);
}

static int vrf_cshake128(dstr *v)
{
  return (vrf_shaky(cshake128_init, &v[0], &v[1], &v[2], &v[3]));
}

static int vrf_cshake256(dstr *v)
{
  return (vrf_shaky(cshake256_init, &v[0], &v[1], &v[2], &v[3]));
}

static void shake128_init_adaptor(shake_ctx *ctx,
                                  const void *func, size_t fsz,
                                  const void *perso, size_t psz)
  { assert(!fsz); assert(!psz); shake128_init(ctx);}

static void shake256_init_adaptor(shake_ctx *ctx,
                                  const void *func, size_t fsz,
                                  const void *perso, size_t psz)
  { assert(!fsz); assert(!psz); shake256_init(ctx);}

static int vrf_shake128(dstr *v)
  { return (vrf_shaky(shake128_init_adaptor, 0, 0, &v[0], &v[1])); }

static int vrf_shake256(dstr *v)
  { return (vrf_shaky(shake256_init_adaptor, 0, 0, &v[0], &v[1])); }

static int vrf_kmac(void (*initfn)(kmac_ctx *, const void *, size_t,
                                   const void *, size_t),
                    dstr *perso, int tsz,
                    dstr *k, dstr *m, dstr *want)
{
  kmac_ctx ctx;
  dstr d = DSTR_INIT;
  int ok = 1;

  if (tsz && tsz != want->len) die(1, "inconsistent tag length request");
  dstr_ensure(&d, want->len); d.len = want->len;
  initfn(&ctx, perso->buf, perso->len, k->buf, k->len);
  kmac_hash(&ctx, m->buf, m->len);
  if (tsz) kmac_done(&ctx, d.buf, tsz);
  else { kmac_xof(&ctx); kmac_get(&ctx, d.buf, d.len); }

  if (MEMCMP(d.buf, !=, want->buf, want->len)) {
    ok = 0;
    printf("\nfail");
    printf("\n\tperso = `%s'", perso->buf);
    printf("\n\ttag size = %d", tsz);
    printf("\n\tkey = "); type_hex.dump(k, stdout);
    printf("\n\tinput = "); type_hex.dump(m, stdout);
    printf("\n\texpected = "); type_hex.dump(want, stdout);
    fputs("\n\tcomputed = ", stdout); type_hex.dump(&d, stdout);
    putchar('\n');
  }

  dstr_destroy(&d);
  return (ok);
}

static int vrf_kmac128(dstr *v)
{
  return (vrf_kmac(kmac128_init, &v[0], *(int *)v[1].buf,
                   &v[2], &v[3], &v[4]));
}

static int vrf_kmac256(dstr *v)
{
  return (vrf_kmac(kmac256_init, &v[0], *(int *)v[1].buf,
                   &v[2], &v[3], &v[4]));
}

static const test_chunk defs[] = {
  HASHES(HASH_TESTDEFSX)
#define VRF_MCTDEF(PRE, pre, name)                                      \
  { name "-mct", vrf_##pre##_mct,                                       \
    { &type_int, &type_hex, &type_hex, 0 } },
  HASHES(VRF_MCTDEF)
#undef VRF_MCTDEF
  { "shake128", vrf_shake128, { &type_hex, &type_hex, 0 } },
  { "shake256", vrf_shake256, { &type_hex, &type_hex, 0 } },
  { "cshake128", vrf_cshake128,
    { &type_string, &type_string, &type_hex, &type_hex, 0 } },
  { "cshake256", vrf_cshake256,
    { &type_string, &type_string, &type_hex, &type_hex, 0 } },
  { "kmac128", vrf_kmac128,
    { &type_string, &type_int, &type_hex, &type_hex, &type_hex, 0 } },
  { "kmac256", vrf_kmac256,
    { &type_string, &type_int, &type_hex, &type_hex, &type_hex, 0 } },
  { 0, 0, { 0 } }
};

int main(int argc, char *argv[])
{
  test_run(argc, argv, defs, SRCDIR"/t/sha3");
  return (0);
}

#endif

/*----- That's all, folks -------------------------------------------------*/