From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001
From: Taru Karttunen <taruti@taruti.net>
Date: Wed, 30 Mar 2011 15:46:40 +0300
Subject: Import sources from 2011-03-30 iso image

---
 sys/src/libsec/port/genrandom.c | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100755 sys/src/libsec/port/genrandom.c

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

diff --git a/sys/src/libsec/port/genrandom.c b/sys/src/libsec/port/genrandom.c
new file mode 100755
index 000000000..2cbaeb8c4
--- /dev/null
+++ b/sys/src/libsec/port/genrandom.c
@@ -0,0 +1,62 @@
+#include "os.h"
+#include <mp.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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