Esempio n. 1
0
static gcry_err_code_t
elg_sign (int algo, gcry_mpi_t *resarr, gcry_mpi_t data, gcry_mpi_t *skey,
          int flags, int hashalgo)
{
  gcry_err_code_t err = GPG_ERR_NO_ERROR;
  ELG_secret_key sk;

  (void)algo;
  (void)flags;
  (void)hashalgo;

  if (mpi_is_opaque (data))
    return GPG_ERR_INV_DATA;

  if ((! data)
      || (! skey[0]) || (! skey[1]) || (! skey[2]) || (! skey[3]))
    err = GPG_ERR_BAD_MPI;
  else
    {
      sk.p = skey[0];
      sk.g = skey[1];
      sk.y = skey[2];
      sk.x = skey[3];
      resarr[0] = mpi_alloc (mpi_get_nlimbs (sk.p));
      resarr[1] = mpi_alloc (mpi_get_nlimbs (sk.p));
      sign (resarr[0], resarr[1], data, &sk);
    }

  return err;
}
Esempio n. 2
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/****************
 * Returns true if the signature composed of A and B is valid.
 */
static int
verify(gcry_mpi_t a, gcry_mpi_t b, gcry_mpi_t input, ELG_public_key *pkey )
{
  int rc;
  gcry_mpi_t t1;
  gcry_mpi_t t2;
  gcry_mpi_t base[4];
  gcry_mpi_t ex[4];

  if( !(mpi_cmp_ui( a, 0 ) > 0 && mpi_cmp( a, pkey->p ) < 0) )
    return 0; /* assertion	0 < a < p  failed */

  t1 = mpi_alloc( mpi_get_nlimbs(a) );
  t2 = mpi_alloc( mpi_get_nlimbs(a) );

#if 0
  /* t1 = (y^a mod p) * (a^b mod p) mod p */
  gcry_mpi_powm( t1, pkey->y, a, pkey->p );
  gcry_mpi_powm( t2, a, b, pkey->p );
  mpi_mulm( t1, t1, t2, pkey->p );

  /* t2 = g ^ input mod p */
  gcry_mpi_powm( t2, pkey->g, input, pkey->p );

  rc = !mpi_cmp( t1, t2 );
#elif 0
  /* t1 = (y^a mod p) * (a^b mod p) mod p */
  base[0] = pkey->y; ex[0] = a;
  base[1] = a;       ex[1] = b;
  base[2] = NULL;    ex[2] = NULL;
  mpi_mulpowm( t1, base, ex, pkey->p );

  /* t2 = g ^ input mod p */
  gcry_mpi_powm( t2, pkey->g, input, pkey->p );

  rc = !mpi_cmp( t1, t2 );
#else
  /* t1 = g ^ - input * y ^ a * a ^ b  mod p */
  mpi_invm(t2, pkey->g, pkey->p );
  base[0] = t2     ; ex[0] = input;
  base[1] = pkey->y; ex[1] = a;
  base[2] = a;       ex[2] = b;
  base[3] = NULL;    ex[3] = NULL;
  mpi_mulpowm( t1, base, ex, pkey->p );
  rc = !mpi_cmp_ui( t1, 1 );

#endif

  mpi_free(t1);
  mpi_free(t2);
  return rc;
}
Esempio n. 3
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/* This function returns a new context for Barrett based operations on
   the modulus M.  This context needs to be released using
   _gcry_mpi_barrett_free.  If COPY is true M will be transferred to
   the context and the user may change M.  If COPY is false, M may not
   be changed until gcry_mpi_barrett_free has been called. */
mpi_barrett_t
_gcry_mpi_barrett_init (gcry_mpi_t m, int copy)
{
  mpi_barrett_t ctx;
  gcry_mpi_t tmp;

  mpi_normalize (m);
  ctx = xcalloc (1, sizeof *ctx);

  if (copy)
    {
      ctx->m = mpi_copy (m);
      ctx->m_copied = 1;
    }
  else
    ctx->m = m;

  ctx->k = mpi_get_nlimbs (m);
  tmp = mpi_alloc (ctx->k + 1);

  /* Barrett precalculation: y = floor(b^(2k) / m). */
  mpi_set_ui (tmp, 1);
  mpi_lshift_limbs (tmp, 2 * ctx->k);
  mpi_fdiv_q (tmp, tmp, m);

  ctx->y  = tmp;
  ctx->r1 = mpi_alloc ( 2 * ctx->k + 1 );
  ctx->r2 = mpi_alloc ( 2 * ctx->k + 1 );

  return ctx;
}
Esempio n. 4
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void
mpi_fdiv_q( MPI quot, MPI dividend, MPI divisor )
{
    MPI tmp = mpi_alloc( mpi_get_nlimbs(quot) );
    mpi_fdiv_qr( quot, tmp, dividend, divisor);
    mpi_free_gpg(tmp);
}
Esempio n. 5
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void
_gcry_mpi_fdiv_q( gcry_mpi_t quot, gcry_mpi_t dividend, gcry_mpi_t divisor )
{
    gcry_mpi_t tmp = mpi_alloc( mpi_get_nlimbs(quot) );
    _gcry_mpi_fdiv_qr( quot, tmp, dividend, divisor);
    mpi_free(tmp);
}
Esempio n. 6
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void
gcry_mpi_div (gcry_mpi_t quot, gcry_mpi_t rem, gcry_mpi_t dividend, gcry_mpi_t divisor, int round)
{
  if (!round)
    {
      if (!rem)
        {
          gcry_mpi_t tmp = mpi_alloc (mpi_get_nlimbs(quot));
          _gcry_mpi_tdiv_qr (quot, tmp, dividend, divisor);
          mpi_free (tmp);
        }
      else
        _gcry_mpi_tdiv_qr (quot, rem, dividend, divisor);
    }
  else if (round < 0)
    {
      if (!rem)
        _gcry_mpi_fdiv_q (quot, dividend, divisor);
      else if (!quot)
        _gcry_mpi_fdiv_r (rem, dividend, divisor);
      else
        _gcry_mpi_fdiv_qr (quot, rem, dividend, divisor);
    }
  else
    log_bug ("mpi rounding to ceiling not yet implemented\n");
}
Esempio n. 7
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/* R = X mod M

   Using Barrett reduction.  Before using this function
   _gcry_mpi_barrett_init must have been called to do the
   precalculations.  CTX is the context created by this precalculation
   and also conveys M.  If the Barret reduction could no be done a
   straightforward reduction method is used.

   We assume that these conditions are met:
   Input:  x =(x_2k-1 ...x_0)_b
 	   m =(m_k-1 ....m_0)_b	  with m_k-1 != 0
   Output: r = x mod m
 */
void
_gcry_mpi_mod_barrett (gcry_mpi_t r, gcry_mpi_t x, mpi_barrett_t ctx)
{
  gcry_mpi_t m = ctx->m;
  int k = ctx->k;
  gcry_mpi_t y = ctx->y;
  gcry_mpi_t r1 = ctx->r1;
  gcry_mpi_t r2 = ctx->r2;
  int sign;

  mpi_normalize (x);
  if (mpi_get_nlimbs (x) > 2*k )
    {
      mpi_mod (r, x, m);
      return;
    }

  sign = x->sign;
  x->sign = 0;

  /* 1. q1 = floor( x / b^k-1)
   *    q2 = q1 * y
   *    q3 = floor( q2 / b^k+1 )
   * Actually, we don't need qx, we can work direct on r2
   */
  mpi_set ( r2, x );
  mpi_rshift_limbs ( r2, k-1 );
  mpi_mul ( r2, r2, y );
  mpi_rshift_limbs ( r2, k+1 );

  /* 2. r1 = x mod b^k+1
   *	r2 = q3 * m mod b^k+1
   *	r  = r1 - r2
   * 3. if r < 0 then  r = r + b^k+1
   */
  mpi_set ( r1, x );
  if ( r1->nlimbs > k+1 ) /* Quick modulo operation.  */
    r1->nlimbs = k+1;
  mpi_mul ( r2, r2, m );
  if ( r2->nlimbs > k+1 ) /* Quick modulo operation. */
    r2->nlimbs = k+1;
  mpi_sub ( r, r1, r2 );

  if ( mpi_has_sign ( r ) )
    {
      if (!ctx->r3)
        {
          ctx->r3 = mpi_alloc ( k + 2 );
          mpi_set_ui (ctx->r3, 1);
          mpi_lshift_limbs (ctx->r3, k + 1 );
        }
      mpi_add ( r, r, ctx->r3 );
    }

  /* 4. while r >= m do r = r - m */
  while ( mpi_cmp( r, m ) >= 0 )
    mpi_sub ( r, r, m );

  x->sign = sign;
}
Esempio n. 8
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gcry_mpi_t
gcry_mpi_set( gcry_mpi_t w, const gcry_mpi_t u )
{
    if( !w )
	w = _gcry_mpi_alloc( mpi_get_nlimbs(u) );
    _gcry_mpi_set( w, (gcry_mpi_t)u );
    return w;
}
Esempio n. 9
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static gcry_err_code_t
ecc_sign (int algo, gcry_mpi_t *resarr, gcry_mpi_t data, gcry_mpi_t *skey)
{
  gpg_err_code_t err;
  ECC_secret_key sk;

  (void)algo;

  if (!data || !skey[0] || !skey[1] || !skey[2] || !skey[3] || !skey[4]
      || !skey[5] || !skey[6] )
    return GPG_ERR_BAD_MPI;

  sk.E.p = skey[0];
  sk.E.a = skey[1];
  sk.E.b = skey[2];
  point_init (&sk.E.G);
  err = os2ec (&sk.E.G, skey[3]);
  if (err)
    {
      point_free (&sk.E.G);
      return err;
    }
  sk.E.n = skey[4];
  point_init (&sk.Q);
  err = os2ec (&sk.Q, skey[5]);
  if (err)
    {
      point_free (&sk.E.G);
      point_free (&sk.Q);
      return err;
    }
  sk.d = skey[6];

  resarr[0] = mpi_alloc (mpi_get_nlimbs (sk.E.p));
  resarr[1] = mpi_alloc (mpi_get_nlimbs (sk.E.p));
  err = sign (data, &sk, resarr[0], resarr[1]);
  if (err)
    {
      mpi_free (resarr[0]);
      mpi_free (resarr[1]);
      resarr[0] = NULL; /* Mark array as released.  */
    }
  point_free (&sk.E.G);
  point_free (&sk.Q);
  return err;
}
Esempio n. 10
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int
elg_encrypt( int algo, MPI *resarr, MPI data, MPI *pkey )
{
    ELG_public_key pk;

    if( !is_ELGAMAL(algo) )
	return G10ERR_PUBKEY_ALGO;
    if( !data || !pkey[0] || !pkey[1] || !pkey[2] )
	return G10ERR_BAD_MPI;

    pk.p = pkey[0];
    pk.g = pkey[1];
    pk.y = pkey[2];
    resarr[0] = mpi_alloc( mpi_get_nlimbs( pk.p ) );
    resarr[1] = mpi_alloc( mpi_get_nlimbs( pk.p ) );
    do_encrypt( resarr[0], resarr[1], data, &pk );
    return 0;
}
Esempio n. 11
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int
mpi_fdiv_q( MPI quot, MPI dividend, MPI divisor )
{
    MPI tmp = mpi_alloc( mpi_get_nlimbs(quot) );
    if (!tmp)
	    return -ENOMEM;
    mpi_fdiv_qr( quot, tmp, dividend, divisor);
    mpi_free(tmp);
    return 0;
}
Esempio n. 12
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/****************
 * Test whether the secret key is valid.
 * Returns: true if this is a valid key.
 */
static int
check_secret_key( RSA_secret_key *sk )
{
  int rc;
  gcry_mpi_t temp = mpi_alloc( mpi_get_nlimbs(sk->p)*2 );
  
  mpi_mul(temp, sk->p, sk->q );
  rc = mpi_cmp( temp, sk->n );
  mpi_free(temp);
  return !rc;
}
Esempio n. 13
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/****************
 * Test whether the secret key is valid.
 * Returns: if this is a valid key.
 */
static int
check_secret_key( ELG_secret_key *sk )
{
  int rc;
  gcry_mpi_t y = mpi_alloc( mpi_get_nlimbs(sk->y) );

  gcry_mpi_powm( y, sk->g, sk->x, sk->p );
  rc = !mpi_cmp( y, sk->y );
  mpi_free( y );
  return rc;
}
Esempio n. 14
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static void
sign(gcry_mpi_t a, gcry_mpi_t b, gcry_mpi_t input, ELG_secret_key *skey )
{
    gcry_mpi_t k;
    gcry_mpi_t t   = mpi_alloc( mpi_get_nlimbs(a) );
    gcry_mpi_t inv = mpi_alloc( mpi_get_nlimbs(a) );
    gcry_mpi_t p_1 = mpi_copy(skey->p);

   /*
    * b = (t * inv) mod (p-1)
    * b = (t * inv(k,(p-1),(p-1)) mod (p-1)
    * b = (((M-x*a) mod (p-1)) * inv(k,(p-1),(p-1))) mod (p-1)
    *
    */
    mpi_sub_ui(p_1, p_1, 1);
    k = gen_k( skey->p, 0 /* no small K ! */ );
    gcry_mpi_powm( a, skey->g, k, skey->p );
    mpi_mul(t, skey->x, a );
    mpi_subm(t, input, t, p_1 );
    mpi_invm(inv, k, p_1 );
    mpi_mulm(b, t, inv, p_1 );

#if 0
    if( DBG_CIPHER ) 
      {
	log_mpidump("elg sign p= ", skey->p);
	log_mpidump("elg sign g= ", skey->g);
	log_mpidump("elg sign y= ", skey->y);
	log_mpidump("elg sign x= ", skey->x);
	log_mpidump("elg sign k= ", k);
	log_mpidump("elg sign M= ", input);
	log_mpidump("elg sign a= ", a);
	log_mpidump("elg sign b= ", b);
      }
#endif
    mpi_free(k);
    mpi_free(t);
    mpi_free(inv);
    mpi_free(p_1);
}
Esempio n. 15
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gcry_err_code_t
_gcry_elg_encrypt (int algo, gcry_mpi_t *resarr,
                   gcry_mpi_t data, gcry_mpi_t *pkey, int flags)
{
  gcry_err_code_t err = GPG_ERR_NO_ERROR;
  ELG_public_key pk;

  (void)algo;
  (void)flags;

  if ((! data) || (! pkey[0]) || (! pkey[1]) || (! pkey[2]))
    err = GPG_ERR_BAD_MPI;
  else
    {
      pk.p = pkey[0];
      pk.g = pkey[1];
      pk.y = pkey[2];
      resarr[0] = mpi_alloc (mpi_get_nlimbs (pk.p));
      resarr[1] = mpi_alloc (mpi_get_nlimbs (pk.p));
      do_encrypt (resarr[0], resarr[1], data, &pk);
    }
  return err;
}
Esempio n. 16
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/****************
 * Barrett precalculation: y = floor(b^(2k) / m)
 */
static gcry_mpi_t
init_barrett( gcry_mpi_t m, int *k, gcry_mpi_t *r1, gcry_mpi_t *r2 )
{
    gcry_mpi_t tmp;

    mpi_normalize( m );
    *k = mpi_get_nlimbs( m );
    tmp = mpi_alloc( *k + 1 );
    mpi_set_ui( tmp, 1 );
    mpi_lshift_limbs( tmp, 2 * *k );
    mpi_fdiv_q( tmp, tmp, m );
    *r1 = mpi_alloc( 2* *k + 1 );
    *r2 = mpi_alloc( 2* *k + 1 );
    return tmp;
}
Esempio n. 17
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gcry_err_code_t
_gcry_elg_sign (int algo, gcry_mpi_t *resarr, gcry_mpi_t data, gcry_mpi_t *skey)
{
  gcry_err_code_t err = GPG_ERR_NO_ERROR;
  ELG_secret_key sk;

  (void)algo;

  if ((! data)
      || (! skey[0]) || (! skey[1]) || (! skey[2]) || (! skey[3]))
    err = GPG_ERR_BAD_MPI;
  else
    {
      sk.p = skey[0];
      sk.g = skey[1];
      sk.y = skey[2];
      sk.x = skey[3];
      resarr[0] = mpi_alloc (mpi_get_nlimbs (sk.p));
      resarr[1] = mpi_alloc (mpi_get_nlimbs (sk.p));
      sign (resarr[0], resarr[1], data, &sk);
    }
  
  return err;
}
Esempio n. 18
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/****************
 * Barrett reduction: We assume that these conditions are met:
 * Given x =(x_2k-1 ...x_0)_b
 *	 m =(m_k-1 ....m_0)_b	  with m_k-1 != 0
 * Output r = x mod m
 * Before using this function init_barret must be used to calucalte y and k.
 * Returns: false = no error
 *	    true = can't perform barret reduction
 */
static int
calc_barrett( gcry_mpi_t r, gcry_mpi_t x, gcry_mpi_t m, gcry_mpi_t y, int k, gcry_mpi_t r1, gcry_mpi_t r2 )
{
    int xx = k > 3 ? k-3:0;

    mpi_normalize( x );
    if( mpi_get_nlimbs(x) > 2*k )
	return 1; /* can't do it */

    /* 1. q1 = floor( x / b^k-1)
     *	  q2 = q1 * y
     *	  q3 = floor( q2 / b^k+1 )
     * Actually, we don't need qx, we can work direct on r2
     */
    mpi_set( r2, x );
    mpi_rshift_limbs( r2, k-1 );
    mpi_mul( r2, r2, y );
    mpi_rshift_limbs( r2, k+1 );

    /* 2. r1 = x mod b^k+1
     *	  r2 = q3 * m mod b^k+1
     *	  r  = r1 - r2
     * 3. if r < 0 then  r = r + b^k+1
     */
    mpi_set( r1, x );
    if( r1->nlimbs > k+1 ) /* quick modulo operation */
	r1->nlimbs = k+1;
    mpi_mul( r2, r2, m );
    if( r2->nlimbs > k+1 ) /* quick modulo operation */
	r2->nlimbs = k+1;
    mpi_sub( r, r1, r2 );

    if( mpi_has_sign (r) ) {
	gcry_mpi_t tmp;

	tmp = mpi_alloc( k + 2 );
	mpi_set_ui( tmp, 1 );
	mpi_lshift_limbs( tmp, k+1 );
	mpi_add( r, r, tmp );
	mpi_free(tmp);
    }

    /* 4. while r >= m do r = r - m */
    while( mpi_cmp( r, m ) >= 0 )
	mpi_sub( r, r, m );

    return 0;
}
Esempio n. 19
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gcry_mpi_t
gcry_mpi_set( gcry_mpi_t w, gcry_mpi_t u)
{
  mpi_ptr_t wp, up;
  mpi_size_t usize = u->nlimbs;
  int usign = u->sign;

  if (!w)
    w = _gcry_mpi_alloc( mpi_get_nlimbs(u) );
  RESIZE_IF_NEEDED(w, usize);
  wp = w->d;
  up = u->d;
  MPN_COPY( wp, up, usize );
  w->nlimbs = usize;
  w->flags = u->flags;
  w->sign = usign;
  return w;
}
Esempio n. 20
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int
elg_decrypt( int algo, MPI *result, MPI *data, MPI *skey )
{
    ELG_secret_key sk;

    if( !is_ELGAMAL(algo) )
	return G10ERR_PUBKEY_ALGO;
    if( !data[0] || !data[1]
	|| !skey[0] || !skey[1] || !skey[2] || !skey[3] )
	return G10ERR_BAD_MPI;

    sk.p = skey[0];
    sk.g = skey[1];
    sk.y = skey[2];
    sk.x = skey[3];
    *result = mpi_alloc_secure( mpi_get_nlimbs( sk.p ) );
    decrypt( *result, data[0], data[1], &sk );
    return 0;
}
Esempio n. 21
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static void
decrypt(gcry_mpi_t output, gcry_mpi_t a, gcry_mpi_t b, ELG_secret_key *skey )
{
  gcry_mpi_t t1 = mpi_alloc_secure( mpi_get_nlimbs( skey->p ) );

  /* output = b/(a^x) mod p */
  gcry_mpi_powm( t1, a, skey->x, skey->p );
  mpi_invm( t1, t1, skey->p );
  mpi_mulm( output, b, t1, skey->p );
#if 0
  if( DBG_CIPHER ) 
    {
      log_mpidump("elg decrypted x= ", skey->x);
      log_mpidump("elg decrypted p= ", skey->p);
      log_mpidump("elg decrypted a= ", a);
      log_mpidump("elg decrypted b= ", b);
      log_mpidump("elg decrypted M= ", output);
    }
#endif
  mpi_free(t1);
}
Esempio n. 22
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gcry_err_code_t
_gcry_elg_decrypt (int algo, gcry_mpi_t *result,
                   gcry_mpi_t *data, gcry_mpi_t *skey, int flags)
{
  gcry_err_code_t err = GPG_ERR_NO_ERROR;
  ELG_secret_key sk;

  (void)algo;
  (void)flags;

  if ((! data[0]) || (! data[1])
      || (! skey[0]) || (! skey[1]) || (! skey[2]) || (! skey[3]))
    err = GPG_ERR_BAD_MPI;
  else
    {
      sk.p = skey[0];
      sk.g = skey[1];
      sk.y = skey[2];
      sk.x = skey[3];
      *result = mpi_alloc_secure (mpi_get_nlimbs (sk.p));
      decrypt (*result, data[0], data[1], &sk);
    }
  return err;
}
Esempio n. 23
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gcry_mpi_t
_gcry_mpi_set (gcry_mpi_t w, gcry_mpi_t u)
{
  mpi_ptr_t wp, up;
  mpi_size_t usize = u->nlimbs;
  int usign = u->sign;

  if (!w)
    w = _gcry_mpi_alloc( mpi_get_nlimbs(u) );
  if (mpi_is_immutable (w))
    {
      mpi_immutable_failed ();
      return w;
    }
  RESIZE_IF_NEEDED(w, usize);
  wp = w->d;
  up = u->d;
  MPN_COPY( wp, up, usize );
  w->nlimbs = usize;
  w->flags = u->flags;
  w->flags &= ~(16|32); /* Reset the immutable and constant flags.  */
  w->sign = usign;
  return w;
}
Esempio n. 24
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/*
 * Generate a random secret exponent K less than Q.
 * Note that ECDSA uses this code also to generate D.
 */
gcry_mpi_t
_gcry_dsa_gen_k (gcry_mpi_t q, int security_level)
{
  gcry_mpi_t k        = mpi_alloc_secure (mpi_get_nlimbs (q));
  unsigned int nbits  = mpi_get_nbits (q);
  unsigned int nbytes = (nbits+7)/8;
  char *rndbuf = NULL;

  /* To learn why we don't use mpi_mod to get the requested bit size,
     read the paper: "The Insecurity of the Digital Signature
     Algorithm with Partially Known Nonces" by Nguyen and Shparlinski.
     Journal of Cryptology, New York. Vol 15, nr 3 (2003)  */

  if (DBG_CIPHER)
    log_debug ("choosing a random k of %u bits at seclevel %d\n",
               nbits, security_level);
  for (;;)
    {
      if ( !rndbuf || nbits < 32 )
        {
          xfree (rndbuf);
          rndbuf = _gcry_random_bytes_secure (nbytes, security_level);
	}
      else
        { /* Change only some of the higher bits.  We could improve
	     this by directly requesting more memory at the first call
	     to get_random_bytes() and use these extra bytes here.
	     However the required management code is more complex and
	     thus we better use this simple method.  */
          char *pp = _gcry_random_bytes_secure (4, security_level);
          memcpy (rndbuf, pp, 4);
          xfree (pp);
	}
      _gcry_mpi_set_buffer (k, rndbuf, nbytes, 0);

      /* Make sure we have the requested number of bits.  This code
         looks a bit funny but it is easy to understand if you
         consider that mpi_set_highbit clears all higher bits.  We
         don't have a clear_highbit, thus we first set the high bit
         and then clear it again.  */
      if (mpi_test_bit (k, nbits-1))
        mpi_set_highbit (k, nbits-1);
      else
        {
          mpi_set_highbit (k, nbits-1);
          mpi_clear_bit (k, nbits-1);
	}

      if (!(mpi_cmp (k, q) < 0))    /* check: k < q */
        {
          if (DBG_CIPHER)
            log_debug ("\tk too large - again\n");
          continue; /* no  */
        }
      if (!(mpi_cmp_ui (k, 0) > 0)) /* check: k > 0 */
        {
          if (DBG_CIPHER)
            log_debug ("\tk is zero - again\n");
          continue; /* no */
        }
      break;	/* okay */
    }
  xfree (rndbuf);

  return k;
}
Esempio n. 25
0


/****************
 * Public key operation. Encrypt INPUT with PKEY and put result into OUTPUT.
 *
 *	c = m^e mod n
 *
 * Where c is OUTPUT, m is INPUT and e,n are elements of PKEY.
 */
static void
public(gcry_mpi_t output, gcry_mpi_t input, RSA_public_key *pkey )
{
  if( output == input )  /* powm doesn't like output and input the same */
    {
      gcry_mpi_t x = mpi_alloc( mpi_get_nlimbs(input)*2 );
      mpi_powm( x, input, pkey->e, pkey->n );
      mpi_set(output, x);
      mpi_free(x);
    }
  else
    mpi_powm( output, input, pkey->e, pkey->n );
}

#if 0
static void
stronger_key_check ( RSA_secret_key *skey )
{
  gcry_mpi_t t = mpi_alloc_secure ( 0 );
  gcry_mpi_t t1 = mpi_alloc_secure ( 0 );
  gcry_mpi_t t2 = mpi_alloc_secure ( 0 );
Esempio n. 26
0
/****************
 * Calculate the multiplicative inverse X of A mod N
 * That is: Find the solution x for
 *		1 = (a*x) mod n
 */
int mpi_invm(MPI x, const MPI a, const MPI n)
{
	/* Extended Euclid's algorithm (See TAOPC Vol II, 4.5.2, Alg X)
	 * modified according to Michael Penk's solution for Exercice 35
	 * with further enhancement */
	MPI u = NULL, v = NULL;
	MPI u1 = NULL, u2 = NULL, u3 = NULL;
	MPI v1 = NULL, v2 = NULL, v3 = NULL;
	MPI t1 = NULL, t2 = NULL, t3 = NULL;
	unsigned k;
	int sign;
	int odd = 0;
	int rc = -ENOMEM;

	if (mpi_copy(&u, a) < 0)
		goto cleanup;
	if (mpi_copy(&v, n) < 0)
		goto cleanup;

	for (k = 0; !mpi_test_bit(u, 0) && !mpi_test_bit(v, 0); k++) {
		if (mpi_rshift(u, u, 1) < 0)
			goto cleanup;
		if (mpi_rshift(v, v, 1) < 0)
			goto cleanup;
	}
	odd = mpi_test_bit(v, 0);

	u1 = mpi_alloc_set_ui(1);
	if (!u1)
		goto cleanup;
	if (!odd) {
		u2 = mpi_alloc_set_ui(0);
		if (!u2)
			goto cleanup;
	}
	if (mpi_copy(&u3, u) < 0)
		goto cleanup;
	if (mpi_copy(&v1, v) < 0)
		goto cleanup;
	if (!odd) {
		v2 = mpi_alloc(mpi_get_nlimbs(u));
		if (!v2)
			goto cleanup;
		if (mpi_sub(v2, u1, u) < 0)
			goto cleanup;	/* U is used as const 1 */
	}
	if (mpi_copy(&v3, v) < 0)
		goto cleanup;
	if (mpi_test_bit(u, 0)) {	/* u is odd */
		t1 = mpi_alloc_set_ui(0);
		if (!t1)
			goto cleanup;
		if (!odd) {
			t2 = mpi_alloc_set_ui(1);
			if (!t2)
				goto cleanup;
			t2->sign = 1;
		}
		if (mpi_copy(&t3, v) < 0)
			goto cleanup;
		t3->sign = !t3->sign;
		goto Y4;
	} else {
		t1 = mpi_alloc_set_ui(1);
		if (!t1)
			goto cleanup;
		if (!odd) {
			t2 = mpi_alloc_set_ui(0);
			if (!t2)
				goto cleanup;
		}
		if (mpi_copy(&t3, u) < 0)
			goto cleanup;
	}
	do {
		do {
			if (!odd) {
				if (mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0)) {	/* one is odd */
					if (mpi_add(t1, t1, v) < 0)
						goto cleanup;
					if (mpi_sub(t2, t2, u) < 0)
						goto cleanup;
				}
				if (mpi_rshift(t1, t1, 1) < 0)
					goto cleanup;
				if (mpi_rshift(t2, t2, 1) < 0)
					goto cleanup;
				if (mpi_rshift(t3, t3, 1) < 0)
					goto cleanup;
			} else {
				if (mpi_test_bit(t1, 0))
					if (mpi_add(t1, t1, v) < 0)
						goto cleanup;
				if (mpi_rshift(t1, t1, 1) < 0)
					goto cleanup;
				if (mpi_rshift(t3, t3, 1) < 0)
					goto cleanup;
			}
Y4:
			;
		} while (!mpi_test_bit(t3, 0));	/* while t3 is even */

		if (!t3->sign) {
			if (mpi_set(u1, t1) < 0)
				goto cleanup;
			if (!odd)
				if (mpi_set(u2, t2) < 0)
					goto cleanup;
			if (mpi_set(u3, t3) < 0)
				goto cleanup;
		} else {
			if (mpi_sub(v1, v, t1) < 0)
				goto cleanup;
			sign = u->sign;
			u->sign = !u->sign;
			if (!odd)
				if (mpi_sub(v2, u, t2) < 0)
					goto cleanup;
			u->sign = sign;
			sign = t3->sign;
			t3->sign = !t3->sign;
			if (mpi_set(v3, t3) < 0)
				goto cleanup;
			t3->sign = sign;
		}
		if (mpi_sub(t1, u1, v1) < 0)
			goto cleanup;
		if (!odd)
			if (mpi_sub(t2, u2, v2) < 0)
				goto cleanup;
		if (mpi_sub(t3, u3, v3) < 0)
			goto cleanup;
		if (t1->sign) {
			if (mpi_add(t1, t1, v) < 0)
				goto cleanup;
			if (!odd)
				if (mpi_sub(t2, t2, u) < 0)
					goto cleanup;
		}
	} while (mpi_cmp_ui(t3, 0));	/* while t3 != 0 */
	/* mpi_lshift( u3, k ); */
	rc = mpi_set(x, u1);

cleanup:
	mpi_free(u1);
	mpi_free(v1);
	mpi_free(t1);
	if (!odd) {
		mpi_free(u2);
		mpi_free(v2);
		mpi_free(t2);
	}
	mpi_free(u3);
	mpi_free(v3);
	mpi_free(t3);

	mpi_free(u);
	mpi_free(v);
	return rc;
}
Esempio n. 27
0
/****************
 * We do not need to use the strongest RNG because we gain no extra
 * security from it - The prime number is public and we could also
 * offer the factors for those who are willing to check that it is
 * indeed a strong prime.  With ALL_FACTORS set to true all afcors of
 * prime-1 are returned in FACTORS.
 *
 * mode 0: Standard
 *	1: Make sure that at least one factor is of size qbits.
 */
static gcry_err_code_t
prime_generate_internal (int mode,
			 gcry_mpi_t *prime_generated, unsigned int pbits,
			 unsigned int qbits, gcry_mpi_t g,
			 gcry_mpi_t **ret_factors,
			 gcry_random_level_t randomlevel, unsigned int flags,
                         int all_factors,
                         gcry_prime_check_func_t cb_func, void *cb_arg)
{
  gcry_err_code_t err = 0;
  gcry_mpi_t *factors_new = NULL; /* Factors to return to the
				     caller.  */
  gcry_mpi_t *factors = NULL;	/* Current factors.  */
  gcry_mpi_t *pool = NULL;	/* Pool of primes.  */
  unsigned char *perms = NULL;	/* Permutations of POOL.  */
  gcry_mpi_t q_factor = NULL;	/* Used if QBITS is non-zero.  */
  unsigned int fbits = 0;	/* Length of prime factors.  */
  unsigned int n = 0;		/* Number of factors.  */
  unsigned int m = 0;		/* Number of primes in pool.  */
  gcry_mpi_t q = NULL;		/* First prime factor.  */
  gcry_mpi_t prime = NULL;	/* Prime candidate.  */
  unsigned int nprime = 0;	/* Bits of PRIME.  */
  unsigned int req_qbits;       /* The original QBITS value.  */
  gcry_mpi_t val_2;             /* For check_prime().  */
  unsigned int is_secret = (flags & GCRY_PRIME_FLAG_SECRET);
  unsigned int count1 = 0, count2 = 0;
  unsigned int i = 0, j = 0;

  if (pbits < 48)
    return GPG_ERR_INV_ARG;

  /* If QBITS is not given, assume a reasonable value. */
  if (!qbits)
    qbits = pbits / 3;

  req_qbits = qbits;

  /* Find number of needed prime factors.  */
  for (n = 1; (pbits - qbits - 1) / n  >= qbits; n++)
    ;
  n--;

  val_2 = mpi_alloc_set_ui (2);

  if ((! n) || ((mode == 1) && (n < 2)))
    {
      err = GPG_ERR_INV_ARG;
      goto leave;
    }

  if (mode == 1)
    {
      n--;
      fbits = (pbits - 2 * req_qbits -1) / n;
      qbits =  pbits - req_qbits - n * fbits;
    }
  else
    {
      fbits = (pbits - req_qbits -1) / n;
      qbits = pbits - n * fbits;
    }
  
  if (DBG_CIPHER)
    log_debug ("gen prime: pbits=%u qbits=%u fbits=%u/%u n=%d\n",
               pbits, req_qbits, qbits, fbits, n);

  prime = gcry_mpi_new (pbits);

  /* Generate first prime factor.  */
  q = gen_prime (qbits, is_secret, randomlevel, NULL, NULL);
  
  if (mode == 1)
    q_factor = gen_prime (req_qbits, is_secret, randomlevel, NULL, NULL);
  
  /* Allocate an array to hold the factors + 2 for later usage.  */
  factors = gcry_calloc (n + 2, sizeof (*factors));
  if (!factors)
    {
      err = gpg_err_code_from_errno (errno);
      goto leave;
    }
      
  /* Make a pool of 3n+5 primes (this is an arbitrary value).  */
  m = n * 3 + 5;
  if (mode == 1) /* Need some more (for e.g. DSA).  */
    m += 5;
  if (m < 25)
    m = 25;
  pool = gcry_calloc (m , sizeof (*pool));
  if (! pool)
    {
      err = gpg_err_code_from_errno (errno);
      goto leave;
    }

  /* Permutate over the pool of primes.  */
  do
    {
    next_try:
      if (! perms)
        {
          /* Allocate new primes.  */
          for(i = 0; i < m; i++)
            {
              mpi_free (pool[i]);
              pool[i] = NULL;
            }

          /* Init m_out_of_n().  */
          perms = gcry_calloc (1, m);
          if (! perms)
            {
              err = gpg_err_code_from_errno (errno);
              goto leave;
            }
          for(i = 0; i < n; i++)
            {
              perms[i] = 1;
              pool[i] = gen_prime (fbits, is_secret,
                                   randomlevel, NULL, NULL);
              factors[i] = pool[i];
            }
        }
      else
        {
          m_out_of_n ((char*)perms, n, m);
          for (i = j = 0; (i < m) && (j < n); i++)
            if (perms[i])
              {
                if(! pool[i])
                  pool[i] = gen_prime (fbits, 0, 1, NULL, NULL);
                factors[j++] = pool[i];
              }
          if (i == n)
            {
              gcry_free (perms);
              perms = NULL;
              progress ('!');
              goto next_try;	/* Allocate new primes.  */
            }
        }

	/* Generate next prime candidate:
	   p = 2 * q [ * q_factor] * factor_0 * factor_1 * ... * factor_n + 1. 
        */
	mpi_set (prime, q);
	mpi_mul_ui (prime, prime, 2);
	if (mode == 1)
	  mpi_mul (prime, prime, q_factor);
	for(i = 0; i < n; i++)
	  mpi_mul (prime, prime, factors[i]);
	mpi_add_ui (prime, prime, 1);
	nprime = mpi_get_nbits (prime);

	if (nprime < pbits)
	  {
	    if (++count1 > 20)
	      {
		count1 = 0;
		qbits++;
		progress('>');
		mpi_free (q);
		q = gen_prime (qbits, 0, 0, NULL, NULL);
		goto next_try;
	      }
	  }
	else
	  count1 = 0;
        
	if (nprime > pbits)
	  {
	    if (++count2 > 20)
	      {
		count2 = 0;
		qbits--;
		progress('<');
		mpi_free (q);
		q = gen_prime (qbits, 0, 0, NULL, NULL);
		goto next_try;
	      }
	  }
	else
	  count2 = 0;
    }
  while (! ((nprime == pbits) && check_prime (prime, val_2, cb_func, cb_arg)));

  if (DBG_CIPHER)
    {
      progress ('\n');
      log_mpidump ("prime    : ", prime);
      log_mpidump ("factor  q: ", q);
      if (mode == 1)
        log_mpidump ("factor q0: ", q_factor);
      for (i = 0; i < n; i++)
        log_mpidump ("factor pi: ", factors[i]);
      log_debug ("bit sizes: prime=%u, q=%u",
                 mpi_get_nbits (prime), mpi_get_nbits (q));
      if (mode == 1)
        log_debug (", q0=%u", mpi_get_nbits (q_factor));
      for (i = 0; i < n; i++)
        log_debug (", p%d=%u", i, mpi_get_nbits (factors[i]));
      progress('\n');
    }

  if (ret_factors)
    {
      /* Caller wants the factors.  */
      factors_new = gcry_calloc (n + 4, sizeof (*factors_new));
      if (! factors_new)
        {
          err = gpg_err_code_from_errno (errno);
          goto leave;
        }

      if (all_factors)
        {
          i = 0;
          factors_new[i++] = gcry_mpi_set_ui (NULL, 2);
          factors_new[i++] = mpi_copy (q);
          if (mode == 1)
            factors_new[i++] = mpi_copy (q_factor);
          for(j=0; j < n; j++)
            factors_new[i++] = mpi_copy (factors[j]);
        }
      else
        {
          i = 0;
          if (mode == 1)
            {
              factors_new[i++] = mpi_copy (q_factor);
              for (; i <= n; i++)
                factors_new[i] = mpi_copy (factors[i]);
            }
          else
            for (; i < n; i++ )
              factors_new[i] = mpi_copy (factors[i]);
        }
    }
  
  if (g)
    {
      /* Create a generator (start with 3).  */
      gcry_mpi_t tmp = mpi_alloc (mpi_get_nlimbs (prime));
      gcry_mpi_t b = mpi_alloc (mpi_get_nlimbs (prime));
      gcry_mpi_t pmin1 = mpi_alloc (mpi_get_nlimbs (prime));
      
      if (mode == 1)
        err = GPG_ERR_NOT_IMPLEMENTED;
      else
        {
          factors[n] = q;
          factors[n + 1] = mpi_alloc_set_ui (2);
          mpi_sub_ui (pmin1, prime, 1);
          mpi_set_ui (g, 2);
          do
            {
              mpi_add_ui (g, g, 1);
              if (DBG_CIPHER)
                {
                  log_debug ("checking g:");
                  gcry_mpi_dump (g);
                  log_printf ("\n");
                }
              else
                progress('^');
              for (i = 0; i < n + 2; i++)
                {
                  mpi_fdiv_q (tmp, pmin1, factors[i]);
                  /* No mpi_pow(), but it is okay to use this with mod
                     prime.  */
                  gcry_mpi_powm (b, g, tmp, prime);
                  if (! mpi_cmp_ui (b, 1))
                    break;
                }
              if (DBG_CIPHER)
                progress('\n');
            } 
          while (i < n + 2);

          mpi_free (factors[n+1]);
          mpi_free (tmp);
          mpi_free (b);
          mpi_free (pmin1);
        }
    }
  
  if (! DBG_CIPHER)
    progress ('\n');


 leave:
  if (pool)
    {
      for(i = 0; i < m; i++)
	mpi_free (pool[i]);
      gcry_free (pool);
    }
  if (factors)
    gcry_free (factors);  /* Factors are shallow copies.  */
  if (perms)
    gcry_free (perms);

  mpi_free (val_2);
  mpi_free (q);
  mpi_free (q_factor);

  if (! err)
    {
      *prime_generated = prime;
      if (ret_factors)
	*ret_factors = factors_new;
    }
  else
    {
      if (factors_new)
	{
	  for (i = 0; factors_new[i]; i++)
	    mpi_free (factors_new[i]);
	  gcry_free (factors_new);
	}
      mpi_free (prime);
    }

  return err;
}
Esempio n. 28
0
/*
 * Return true if n is probably a prime
 */
static int
is_prime (gcry_mpi_t n, int steps, unsigned int *count)
{
  gcry_mpi_t x = mpi_alloc( mpi_get_nlimbs( n ) );
  gcry_mpi_t y = mpi_alloc( mpi_get_nlimbs( n ) );
  gcry_mpi_t z = mpi_alloc( mpi_get_nlimbs( n ) );
  gcry_mpi_t nminus1 = mpi_alloc( mpi_get_nlimbs( n ) );
  gcry_mpi_t a2 = mpi_alloc_set_ui( 2 );
  gcry_mpi_t q;
  unsigned i, j, k;
  int rc = 0;
  unsigned nbits = mpi_get_nbits( n );

  mpi_sub_ui( nminus1, n, 1 );

  /* Find q and k, so that n = 1 + 2^k * q . */
  q = mpi_copy ( nminus1 );
  k = mpi_trailing_zeros ( q );
  mpi_tdiv_q_2exp (q, q, k);

  for (i=0 ; i < steps; i++ )
    {
      ++*count;
      if( !i )
        {
          mpi_set_ui( x, 2 );
        }
      else
        {
          gcry_mpi_randomize( x, nbits, GCRY_WEAK_RANDOM );

          /* Make sure that the number is smaller than the prime and
             keep the randomness of the high bit. */
          if ( mpi_test_bit ( x, nbits-2) )
            {
              mpi_set_highbit ( x, nbits-2); /* Clear all higher bits. */
            }
          else
            {
              mpi_set_highbit( x, nbits-2 );
              mpi_clear_bit( x, nbits-2 );
            }
          assert ( mpi_cmp( x, nminus1 ) < 0 && mpi_cmp_ui( x, 1 ) > 0 );
	}
      gcry_mpi_powm ( y, x, q, n);
      if ( mpi_cmp_ui(y, 1) && mpi_cmp( y, nminus1 ) )
        {
          for ( j=1; j < k && mpi_cmp( y, nminus1 ); j++ )
            {
              gcry_mpi_powm(y, y, a2, n);
              if( !mpi_cmp_ui( y, 1 ) )
                goto leave; /* Not a prime. */
            }
          if (mpi_cmp( y, nminus1 ) )
            goto leave; /* Not a prime. */
	}
      progress('+');
    }
  rc = 1; /* May be a prime. */

 leave:
  mpi_free( x );
  mpi_free( y );
  mpi_free( z );
  mpi_free( nminus1 );
  mpi_free( q );
  mpi_free( a2 );

  return rc;
}
Esempio n. 29
0
/****************
 * Generate a random secret exponent k from prime p, so that k is
 * relatively prime to p-1.  With SMALL_K set, k will be selected for
 * better encryption performance - this must never be used signing!
 */
static gcry_mpi_t
gen_k( gcry_mpi_t p, int small_k )
{
  gcry_mpi_t k = mpi_alloc_secure( 0 );
  gcry_mpi_t temp = mpi_alloc( mpi_get_nlimbs(p) );
  gcry_mpi_t p_1 = mpi_copy(p);
  unsigned int orig_nbits = mpi_get_nbits(p);
  unsigned int nbits, nbytes;
  char *rndbuf = NULL;

  if (small_k)
    {
      /* Using a k much lesser than p is sufficient for encryption and
       * it greatly improves the encryption performance.  We use
       * Wiener's table and add a large safety margin. */
      nbits = wiener_map( orig_nbits ) * 3 / 2;
      if( nbits >= orig_nbits )
        BUG();
    }
  else
    nbits = orig_nbits;


  nbytes = (nbits+7)/8;
  if( DBG_CIPHER )
    log_debug("choosing a random k ");
  mpi_sub_ui( p_1, p, 1);
  for(;;) 
    {
      if( !rndbuf || nbits < 32 ) 
        {
          gcry_free(rndbuf);
          rndbuf = gcry_random_bytes_secure( nbytes, GCRY_STRONG_RANDOM );
        }
      else
        { 
          /* Change only some of the higher bits.  We could improve
             this by directly requesting more memory at the first call
             to get_random_bytes() and use this the here maybe it is
             easier to do this directly in random.c Anyway, it is
             highly inlikely that we will ever reach this code. */
          char *pp = gcry_random_bytes_secure( 4, GCRY_STRONG_RANDOM );
          memcpy( rndbuf, pp, 4 );
          gcry_free(pp);
	}
      _gcry_mpi_set_buffer( k, rndbuf, nbytes, 0 );
        
      for(;;)
        {
          if( !(mpi_cmp( k, p_1 ) < 0) )  /* check: k < (p-1) */
            {
              if( DBG_CIPHER )
                progress('+');
              break; /* no  */
            }
          if( !(mpi_cmp_ui( k, 0 ) > 0) )  /* check: k > 0 */
            {
              if( DBG_CIPHER )
                progress('-');
              break; /* no */
            }
          if (gcry_mpi_gcd( temp, k, p_1 ))
            goto found;  /* okay, k is relative prime to (p-1) */
          mpi_add_ui( k, k, 1 );
          if( DBG_CIPHER )
            progress('.');
	}
    }
 found:
  gcry_free(rndbuf);
  if( DBG_CIPHER )
    progress('\n');
  mpi_free(p_1);
  mpi_free(temp);

  return k;
}
Esempio n. 30
0
/****************
 * RES = (BASE[0] ^ EXP[0]) *  (BASE[1] ^ EXP[1]) * ... * mod M
 */
int
mpi_mulpowm( MPI res, MPI *basearray, MPI *exparray, MPI m)
{
	int rc = -ENOMEM;
	int k;	/* number of elements */
	int t;	/* bit size of largest exponent */
	int i, j, idx;
	MPI *G = NULL;	/* table with precomputed values of size 2^k */
	MPI tmp = NULL;

	for(k=0; basearray[k]; k++ )
		;
	if (!k) { printk("mpi_mulpowm: assert(k) failed\n"); BUG(); }
	for(t=0, i=0; (tmp=exparray[i]); i++ ) {
		j = mpi_get_nbits(tmp);
		if( j > t )
			t = j;
	}
	if (i!=k) { printk("mpi_mulpowm: assert(i==k) failed\n"); BUG(); }
	if (!t)	  { printk("mpi_mulpowm: assert(t) failed\n"); BUG(); }
	if (k>=10) { printk("mpi_mulpowm: assert(k<10) failed\n"); BUG(); }

//daveti: hack
	//G = kzalloc( (1<<k) * sizeof *G, GFP_KERNEL );
	G = kzalloc( (1<<k) * sizeof *G, GFP_ATOMIC );
	if (!G) goto nomem;

	/* and calculate */
	tmp =  mpi_alloc( mpi_get_nlimbs(m)+1 ); if (!tmp) goto nomem;
	if (mpi_set_ui( res, 1 ) < 0) goto nomem;
	for(i = 1; i <= t; i++ ) {
		if (mpi_mulm(tmp, res, res, m ) < 0) goto nomem;
		idx = build_index( exparray, k, i, t );
		if (!(idx >= 0 && idx < (1<<k))) {
			printk("mpi_mulpowm: assert(idx >= 0 && idx < (1<<k)) failed\n");
			BUG();
		}
		if( !G[idx] ) {
			if( !idx ) {
				G[0] = mpi_alloc_set_ui( 1 );
				if (!G[0]) goto nomem;
			}
			else {
				for(j=0; j < k; j++ ) {
					if( (idx & (1<<j) ) ) {
						if( !G[idx] ) {
							if (mpi_copy( &G[idx], basearray[j] ) < 0)
								goto nomem;
						}
						else {
							if (mpi_mulm(G[idx],G[idx],basearray[j],m) < 0)
								goto nomem;
						}
					}
				}
				if( !G[idx] ) {
					G[idx] = mpi_alloc(0);
					if (!G[idx]) goto nomem;
				}
			}
		}
		if (mpi_mulm(res, tmp, G[idx], m ) < 0) goto nomem;
	}

	rc = 0;
 nomem:
	/* cleanup */
	mpi_free(tmp);
	for(i=0; i < (1<<k); i++ )
		mpi_free(G[i]);
	kfree(G);
	return rc;
}