X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/math/ec-raw.c

diff --git a/math/ec-raw.c b/math/ec-raw.c
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+/* -*-c-*-
+ *
+ * Raw formatting of elliptic curve points
+ *
+ * (c) 2004 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 "ec.h"
+#include "ec-raw.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @ec_putraw@ --- *
+ *
+ * Arguments:	@ec_curve *c@ = elliptic curve
+ *		@buf *b@ = pointer to a buffer
+ *		@const ec *p@ = an elliptic curve point
+ *
+ * Returns:	Zero on success, nonzero on failure.
+ *
+ * Use:		Puts an elliptic curve point to the given buffer using the
+ *		standard uncompressed format described in P1383 and SEC1.
+ *		This requires at most @1 + 2 * c->f->noctets@ space in the
+ *		buffer.  We don't do point compression.
+ */
+
+int ec_putraw(ec_curve *c, buf *b, const ec *p)
+{
+  octet *q;
+  size_t n;
+
+  if (EC_ATINF(p)) return (buf_putbyte(b, 0));
+  buf_putbyte(b, 4);
+  n = c->f->noctets;
+  if ((q = buf_get(b, n * 2)) == 0) return (-1);
+  mp_storeb(p->x, q, n);
+  mp_storeb(p->y, q + n, n);
+  return (0);
+}
+
+/* --- @ec_getraw@ --- *
+ *
+ * Arguments:	@ec_curve *c@ = elliptic curve
+ *		@buf *b@ = pointer to a buffer
+ *		@ec *d@ = an elliptic curve point
+ *
+ * Returns:	Zero on success, nonzero on failure.
+ *
+ * Use:		Reads an elliptic curve point from the given buffer using the
+ *		standard uncompressed format described in P1383 and SEC1.
+ *		We don't do point compression.
+ */
+
+int ec_getraw(ec_curve *c, buf *b, ec *d)
+{
+  const octet *q;
+  size_t n;
+  int u;
+
+  if ((u = buf_getbyte(b)) < 0) return (-1);
+  if (!u) { EC_SETINF(d); return (0); }
+  if (!(u & 4)) return (-1);
+  n = c->f->noctets;
+  if ((q = buf_get(b, n * 2)) == 0) return (-1);
+  EC_DESTROY(d);
+  d->x = mp_loadb(MP_NEW, q, n);
+  d->y = mp_loadb(MP_NEW, q + n, n);
+  d->z = 0;
+  return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/