(dsa_keypair_from_sexp_alist, dsa_keypair_from_sexp):

New file, new functions.

Rev: src/nettle/sexp2dsa.c:1.1

sexp2dsa.c

+/* sexp2dsa.c
+ *
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 Niels Mller
+ *  
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ * 
+ * The nettle library 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 Lesser General Public
+ * License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#if WITH_PUBLIC_KEY
+
+#include "dsa.h"
+
+#include "bignum.h"
+#include "sexp.h"
+
+#include <string.h>
+
+#define GET(x, l, v) \
+do { if (!nettle_mpz_set_sexp((x), (l), (v))) return 0; } while(0)
+
+/* Iterator should point past the algorithm tag, e.g.
+ *
+ *   (public-key (dsa (p |xxxx|) ...)
+ *                    ^ here
+ */
+
+int
+dsa_keypair_from_sexp_alist(struct dsa_public_key *pub,
+			    struct dsa_private_key *priv,
+			    unsigned limit,
+			    struct sexp_iterator *i)
+{
+  static const uint8_t *names[5]
+    = { "p", "q", "g", "y", "x" };
+  struct sexp_iterator values[5];
+  unsigned nvalues = priv ? 5 : 4;
+  
+  if (!sexp_iterator_assoc(i, nvalues, names, values))
+    return 0;
+
+  if (priv)
+    GET(priv->x, limit, &values[4]);
+  
+  GET(pub->p, limit, &values[0]);
+  GET(pub->q, DSA_Q_BITS, &values[1]);
+  GET(pub->g, limit, &values[2]);
+  GET(pub->y, limit, &values[3]);
+  
+  return 1;
+}
+
+int
+dsa_keypair_from_sexp(struct dsa_public_key *pub,
+		      struct dsa_private_key *priv,
+		      unsigned limit, 
+		      unsigned length, const uint8_t *expr)
+{
+  struct sexp_iterator i;
+
+  return sexp_iterator_first(&i, length, expr)
+    && sexp_iterator_check_type(&i, priv ? "private-key" : "public-key")
+    && sexp_iterator_check_type(&i, "dsa")
+    && dsa_keypair_from_sexp_alist(pub, priv, limit, &i);
+}
+
+#endif /* WITH_PUBLIC_KEY */