From db6608bd819d10cc2ddb57d18054d62d4ca15596 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sun, 23 Nov 2003 18:21:42 +0000
Subject: add libsec

---
 src/libsec/port/genrandom.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/libsec/port/genrandom.c

(limited to 'src/libsec/port/genrandom.c')

diff --git a/src/libsec/port/genrandom.c b/src/libsec/port/genrandom.c
new file mode 100644
index 00000000..294111e2
--- /dev/null
+++ b/src/libsec/port/genrandom.c
@@ -0,0 +1,61 @@
+#include "os.h"
+#include <libsec.h>
+
+typedef struct State{
+	QLock		lock;
+	int		seeded;
+	uvlong		seed;
+	DES3state	des3;
+} State;
+static State x917state;
+
+static void
+X917(uchar *rand, int nrand)
+{
+	int i, m, n8;
+	uvlong I, x;
+
+	/* 1. Compute intermediate value I = Ek(time). */
+	I = nsec();
+	triple_block_cipher(x917state.des3.expanded, (uchar*)&I, 0); /* two-key EDE */
+
+	/* 2. x[i] = Ek(I^seed);  seed = Ek(x[i]^I); */
+	m = (nrand+7)/8;
+	for(i=0; i<m; i++){
+		x = I ^ x917state.seed;
+		triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);
+		n8 = (nrand>8) ? 8 : nrand;
+		memcpy(rand, (uchar*)&x, n8);
+		rand += 8;
+		nrand -= 8;
+		x ^= I;
+		triple_block_cipher(x917state.des3.expanded, (uchar*)&x, 0);
+		x917state.seed = x;
+	}
+}
+
+static void
+X917init(void)
+{
+	int n;
+	uchar mix[128];
+	uchar key3[3][8];
+	ulong *ulp;
+
+	ulp = (ulong*)key3;
+	for(n = 0; n < sizeof(key3)/sizeof(ulong); n++)
+		ulp[n] = truerand();
+	setupDES3state(&x917state.des3, key3, nil);
+	X917(mix, sizeof mix);
+	x917state.seeded = 1;
+}
+
+void
+genrandom(uchar *p, int n)
+{
+	qlock(&x917state.lock);
+	if(x917state.seeded == 0)
+		X917init();
+	X917(p, n);
+	qunlock(&x917state.lock);
+}
-- 
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