1 files changed, 60 insertions, 0 deletions

diff --git a/src/math/random.c b/src/math/random.c
new file mode 100644
index 0000000..319ed3c
--- /dev/null
+++ b/src/math/random.c
@@ -0,0 +1,60 @@
+/*
+ * ecgen, tool for generating Elliptic curve domain parameters
+ * Copyright (C) 2017 J08nY
+ */
+#include "random.h"
+#include <time.h>
+
+bool random_init() {
+	pari_ulong seed = 0;
+	// Try urandom first
+	FILE *rand = fopen("/dev/urandom", "rb");
+	if (rand) {
+		fread(&seed, sizeof(char), sizeof(pari_ulong), rand);
+		fclose(rand);
+	}
+	// Try worse methods later
+	if (seed == 0) {
+		struct timespec t;
+		if (!clock_gettime(CLOCK_REALTIME, &t)) {
+			seed = (pari_ulong)t.tv_nsec;
+		} else {
+			seed = (pari_ulong)time(NULL);
+		}
+	}
+
+	pari_sp ltop = avma;
+	setrand(utoi(seed));
+	avma = ltop;
+
+	return true;
+}
+
+GEN random_prime(long bits) {
+	pari_sp ltop = avma;
+
+	GEN range = gtovec0(gen_0, 2);
+	gel(range, 1) = powis(gen_2, bits - 1);
+	gel(range, 2) = powis(gen_2, bits);
+
+	GEN p;
+	{
+		pari_sp btop = avma;
+		do {
+			p = randomprime(range);
+			if (gc_needed(btop, 1)) p = gerepilecopy(btop, p);
+		} while (!isprime(p));
+	}
+
+	return gerepilecopy(ltop, p);
+}
+
+GEN random_int(long bits) {
+	pari_sp ltop = avma;
+
+	GEN range = gtovec0(gen_0, 2);
+	gel(range, 1) = powis(gen_2, bits - 1);
+	gel(range, 2) = powis(gen_2, bits);
+
+	return gerepilecopy(ltop, genrand(range));
+}
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