RND: first try of random module

Currently only works with specifying the number
of negative and positive ones.

src/Makefile

@@ -10,7 +10,8 @@ PQC_SOURCES = poly.c \
 			  ascii_poly.c \
 			  file.c \
 			  ntru_string.c \
-			  poly_ascii.c
+			  poly_ascii.c \
+			  rnd.c
 
 PQC_OBJS = $(patsubst %.c, %.o, $(PQC_SOURCES))
 
@@ -24,7 +25,8 @@ PQC_HEADERS = err.h \
 			  common.h \
 			  file.h \
 			  ntru_string.h \
-			  poly_ascii.h
+			  poly_ascii.h \
+			  rnd.h
 
 # libs
 LIBS += -L. -lgmp -lmpfr -lflint $(shell $(PKG_CONFIG) --libs glib-2.0) -lm
@@ -32,6 +34,8 @@ LIBS += -L. -lgmp -lmpfr -lflint $(shell $(PKG_CONFIG) --libs glib-2.0) -lm
 # includes
 INCS = -I. -I/usr/include/flint $(shell $(PKG_CONFIG) --cflags glib-2.0)
 
+CFLAGS += -D_XOPEN_SOURCE -D_XOPEN_SOURCE_EXTENDED
+
 
 %.o: %.c
 	$(CC) -fPIC $(CFLAGS) $(CPPFLAGS) $(INCS) -c $*.c

src/rnd.c

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2014 FH Bielefeld
+ *
+ * This file is part of a FH Bielefeld project.
+ *
+ * This 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.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA  02110-1301  USA
+ */
+
+/**
+ * @file rnd.c
+ * This file allows generation of random polynomials.
+ * @brief random polynomials
+ */
+
+#include "context.h"
+#include "err.h"
+#include "math.h"
+#include "poly.h"
+
+#include <fmpz_poly.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+
+/*------------------------------------------------------------------------*/
+
+static int
+get_rnd_int(void)
+{
+	int rnd_data = open("/dev/random", O_RDONLY);
+	int rnd_int;
+	size_t rnd_len = 0;
+
+	while (rnd_len < sizeof(rnd_int)) {
+		ssize_t result = read(rnd_data, ((char*)&rnd_int) + rnd_len,
+				sizeof(rnd_int) - rnd_len);
+
+		if (result < 0)
+			NTRU_ABORT("Unable to read /dev/random!\n");
+
+		rnd_len += result;
+	}
+
+	close(rnd_data);
+
+	return rnd_int;
+}
+
+/*------------------------------------------------------------------------*/
+
+static int
+get_urnd_int(void)
+{
+	int rnd_data = open("/dev/urandom", O_RDONLY);
+	int rnd_int;
+	ssize_t result;
+
+	result = read(rnd_data, ((char*)&rnd_int),
+			sizeof(rnd_int));
+
+	if (result < 0)
+		NTRU_ABORT("Unable to read /dev/urandom!\n");
+
+	close(rnd_data);
+
+	return rnd_int;
+}
+
+/*------------------------------------------------------------------------*/
+
+void
+ntru_get_rnd_tern_poly_num(fmpz_poly_t poly,
+		const ntru_context *ctx,
+		uint32_t num_ones,
+		uint32_t num_neg_ones)
+{
+	if (!poly || ! ctx)
+		NTRU_ABORT("unexpected NULL parameters in"
+				"ntru_get_rnd_tern_poly_num()!\n");
+
+	fmpz_poly_zero(poly);
+
+	while (num_ones != 0 || num_neg_ones != 0) {
+		int32_t pos = get_rnd_int() % ctx->N;
+
+		if (!fmpz_cmp_si_n(fmpz_poly_get_coeff_ptr(poly, pos), 0)) {
+			if (num_ones > 0) {
+				fmpz_poly_set_coeff_si(poly, pos, 1);
+				num_ones--;
+			} else if (num_neg_ones > 0) {
+				fmpz_poly_set_coeff_si(poly, pos, -1);
+				num_neg_ones--;
+			}
+		}
+	}
+}
+
+/*------------------------------------------------------------------------*/

src/rnd.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2014 FH Bielefeld
+ *
+ * This file is part of a FH Bielefeld project.
+ *
+ * This 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.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA  02110-1301  USA
+ */
+
+/**
+ * @file rnd.h
+ * Header for the internal API of rnd.c.
+ * @brief header for rnd.c
+ */
+
+#ifndef NTRU_RND_H
+#define NTRU_RND_H
+
+#include "context.h"
+
+#include <stdlib.h>
+
+#include <fmpz_poly.h>
+
+
+/**
+ * Get a random ternary polynomial with specified numbers
+ * of 1 coefficients and -1 coefficients.
+ *
+ * @param poly the resulting random polynomial [out]
+ * @param ctx the NTRU context
+ * @param num_ones the number of 1 coefficients
+ * @param num_neg_ones the number of -1 coefficients
+ */
+void
+ntru_get_rnd_tern_poly_num(fmpz_poly_t poly,
+		const ntru_context *ctx,
+		uint32_t num_ones,
+		uint32_t num_neg_ones);
+
+
+#endif /* NTRU_RND_H */