construction time.
/* -*-c-*-
*
- * $Id: gfshare.c,v 1.5 2000/06/24 19:11:47 mdw Exp $
+ * $Id: gfshare.c,v 1.6 2000/12/06 20:30:10 mdw Exp $
*
* Secret sharing over %$\gf(2^8)$%
*
/*----- Revision history --------------------------------------------------*
*
* $Log: gfshare.c,v $
+ * Revision 1.6 2000/12/06 20:30:10 mdw
+ * Change secret sharing interface: present the secret at share
+ * construction time.
+ *
* Revision 1.5 2000/06/24 19:11:47 mdw
* Fix daft error in the comment for @gfshare_get@.
*
s->t = t;
s->i = 0;
s->sz = sz;
- s->s = 0;
s->v = 0;
}
*
* Arguments: @gfshare *s@ = pointer to share context to fill in
* @grand *r@ = pointer to random number source
+ * @const void *buf@ = pointer to the secret to share
*
* Returns: ---
*
* Use: Initializes a sharing context to be able to create shares.
* The context structure is expected to be mostly filled in. In
- * particular, @t@ and @s@ must be initialized. If @v@ is zero,
- * a vector of appropriate size is allocated. You should use
- * the macro @GFSHARE_INIT@ or @gfshare_create@ to construct
- * sharing contexts.
+ * particular, @t@ must be initialized. If @v@ is zero, a
+ * vector of appropriate size is allocated. You should use the
+ * macro @GFSHARE_INIT@ or @gfshare_create@ to construct sharing
+ * contexts.
*/
-void gfshare_mkshares(gfshare *s, grand *r)
+void gfshare_mkshares(gfshare *s, grand *r, const void *buf)
{
s->v = XS_ALLOC(s->sz * s->t);
r->ops->fill(r, s->v, s->sz * (s->t - 1));
- memcpy(s->v + s->sz * (s->t - 1), s->s, s->sz);
+ memcpy(s->v + s->sz * (s->t - 1), buf, s->sz);
}
/* --- @gfshare_get@ --- *
r->ops->fill(r, sec, len);
gfshare_create(&s, t, len);
- s.s = sec;
- gfshare_mkshares(&s, r);
+ gfshare_mkshares(&s, r, sec);
for (i = 0; i < t; i++)
gfshare_get(&s, p[i], v + (i * len));
gfshare_destroy(&s);
/* -*-c-*-
*
- * $Id: gfshare.h,v 1.5 2000/06/24 19:11:47 mdw Exp $
+ * $Id: gfshare.h,v 1.6 2000/12/06 20:30:10 mdw Exp $
*
* Secret sharing over %$\gf{2^8}$%
*
/*----- Revision history --------------------------------------------------*
*
* $Log: gfshare.h,v $
+ * Revision 1.6 2000/12/06 20:30:10 mdw
+ * Change secret sharing interface: present the secret at share
+ * construction time.
+ *
* Revision 1.5 2000/06/24 19:11:47 mdw
* Fix daft error in the comment for @gfshare_get@.
*
unsigned t; /* Threshold */
unsigned i; /* Next free slot in vector */
size_t sz; /* Size of the secret and shares */
- void *s; /* The secret */
octet *v; /* Vector of share information */
} gfshare;
-#define GFSHARE_INIT(t, sz) { t, 0, sz, 0, 0 }
+#define GFSHARE_INIT(t, sz) { t, 0, sz, 0 }
/*----- Functions provided ------------------------------------------------*/
*
* Arguments: @gfshare *s@ = pointer to share context to fill in
* @grand *r@ = pointer to random number source
+ * @const void *buf@ = pointer to the secret to share
*
* Returns: ---
*
* Use: Initializes a sharing context to be able to create shares.
* The context structure is expected to be mostly filled in. In
- * particular, @t@ and @s@ must be initialized. If @v@ is zero,
- * a vector of appropriate size is allocated. You should use
- * the macro @GFSHARE_INIT@ or @gfshare_create@ to construct
- * sharing contexts.
+ * particular, @t@ must be initialized. If @v@ is zero, a
+ * vector of appropriate size is allocated. You should use the
+ * macro @GFSHARE_INIT@ or @gfshare_create@ to construct sharing
+ * contexts.
*/
-extern void gfshare_mkshares(gfshare */*s*/, grand */*r*/);
+extern void gfshare_mkshares(gfshare */*s*/, grand */*r*/,
+ const void */*buf*/);
/* --- @gfshare_get@ --- *
*
/* -*-c-*-
*
- * $Id: share.c,v 1.4 2000/10/08 12:16:17 mdw Exp $
+ * $Id: share.c,v 1.5 2000/12/06 20:30:10 mdw Exp $
*
* Shamir's secret sharing
*
/*----- Revision history --------------------------------------------------*
*
* $Log: share.c,v $
+ * Revision 1.5 2000/12/06 20:30:10 mdw
+ * Change secret sharing interface: present the secret at share
+ * construction time.
+ *
* Revision 1.4 2000/10/08 12:16:17 mdw
* Use @MP_EQ@ instead of @MP_CMP@.
*
{
s->t = t;
s->i = 0;
- s->s = 0;
s->p = 0;
s->v = 0;
}
if (s->p)
mp_drop(s->p);
- if (s->s)
- mp_drop(s->s);
}
/* --- @share_mkshares@ --- *
*
* Arguments: @share *s@ = pointer to share context to fill in
* @grand *r@ = pointer to random number source
+ * @mp *n@ = the secret to share
*
* Returns: ---
*
* Use: Initializes a sharing context to be able to create shares.
* The context structure is expected to be mostly filled in. In
- * particular, @t@ and @s@ must be initialized. If @p@ is zero,
- * a prime number of appropriate size is generated
- * automatically. If @v@ is zero, a vector of appropriate size
- * is allocated. You should use the macro @SHARE_INIT@ or
- * @share_create@ to construct sharing contexts.
+ * particular, @t@ must be initialized. If @p@ is zero, a prime
+ * number of appropriate size is generated automatically. If
+ * @v@ is zero, a vector of appropriate size is allocated. You
+ * should use the macro @SHARE_INIT@ or @share_create@ to
+ * construct sharing contexts.
*/
-void share_mkshares(share *s, grand *r)
+void share_mkshares(share *s, grand *r, mp *n)
{
unsigned i;
pgen_filterctx pf;
rabin pr;
mp *p;
- unsigned bits = (mp_octets(s->s) + 1) * 8;
+ unsigned bits = (mp_octets(n) + 1) * 8;
pf.step = 2;
p = mprand(MP_NEW, bits, r, 1);
s->v = xmalloc(s->t * sizeof(share_pt));
for (i = 0; i < s->t - 1; i++)
s->v[i].y = mprand_range(MP_NEWSEC, s->p, r, 0);
- s->v[s->t - 1].y = mp_copy(s->s);
+ s->v[s->t - 1].y = mp_copy(n);
}
/* --- @share_get@ --- *
}
a = mpbarrett_reduce(&mb, a, a);
- s->s = mp_copy(a);
if (m)
mp_drop(m);
mpbarrett_destroy(&mb);
}
share_create(&s, t);
- s.s = mp_copy(sec);
- share_mkshares(&s, r);
+ share_mkshares(&s, r, sec);
for (i = 0; i < t; i++)
v[i] = share_get(&s, MP_NEW, p[i]);
pp = mp_copy(s.p);
/* -*-c-*-
*
- * $Id: share.h,v 1.2 2000/06/24 18:29:05 mdw Exp $
+ * $Id: share.h,v 1.3 2000/12/06 20:30:10 mdw Exp $
*
* Shamir's secret sharing
*
/*----- Revision history --------------------------------------------------*
*
* $Log: share.h,v $
+ * Revision 1.3 2000/12/06 20:30:10 mdw
+ * Change secret sharing interface: present the secret at share
+ * construction time.
+ *
* Revision 1.2 2000/06/24 18:29:05 mdw
* Interface change: allow shares to be extracted from a context on demand,
* rather than building them all up-front.
typedef struct share {
unsigned t; /* Threshold */
unsigned i; /* Next free slot in the vector */
- mp *s; /* The secret */
mp *p; /* Modulus for arithmetic */
share_pt *v; /* Vector of share information */
} share;
-#define SHARE_INIT(t) { t, 0, 0, 0, 0 }
+#define SHARE_INIT(t) { t, 0, 0, 0 }
/*----- Functions provided ------------------------------------------------*/
*
* Arguments: @share *s@ = pointer to share context to fill in
* @grand *r@ = pointer to random number source
+ * @mp *n@ = the secret to share
*
* Returns: ---
*
* Use: Initializes a sharing context to be able to create shares.
* The context structure is expected to be mostly filled in. In
- * particular, @t@ and @s@ must be initialized. If @p@ is zero,
- * a prime number of appropriate size is generated
- * automatically. If @v@ is zero, a vector of appropriate size
- * is allocated. You should use the macro @SHARE_INIT@ or
- * @share_create@ to construct sharing contexts.
+ * particular, @t@ must be initialized. If @p@ is zero, a prime
+ * number of appropriate size is generated automatically. If
+ * @v@ is zero, a vector of appropriate size is allocated. You
+ * should use the macro @SHARE_INIT@ or @share_create@ to
+ * construct sharing contexts.
*/
-extern void share_mkshares(share */*s*/, grand */*r*/);
+extern void share_mkshares(share */*s*/, grand */*r*/, mp */*n*/);
/* --- @share_get@ --- *
*
projects / u / mdw / catacomb / commitdiff