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diff --git a/lib/libc/gen/arc4random.3 b/lib/libc/gen/arc4random.3
new file mode 100644
index 000000000000..25c6d4d0a02e
--- /dev/null
+++ b/lib/libc/gen/arc4random.3
@@ -0,0 +1,83 @@
+.\" $OpenBSD: arc4random.3,v 1.2 1997/04/27 22:40:25 angelos Exp $
+.\" Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"      This product includes software developed by Niels Provos.
+.\" 4. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" Manual page, using -mandoc macros
+.\"
+.Dd April 15, 1997
+.Dt ARC4RANDOM 3
+.Os
+.Sh NAME
+.Nm arc4random,
+.Nm arc4random_stir,
+.Nm arc4random_addrandom
+.Nd arc4 random number generator.
+.Sh SYNOPSIS
+.Fd #include <stdlib.h>
+.Ft u_int32_t
+.Fn arc4random "void"
+.Ft void
+.Fn arc4random_stir "void"
+.Ft void
+.Fn arc4random_addrandom "unsigned char *dat" "int datlen"
+.Sh DESCRIPTION
+The
+.Fn arc4random 
+function uses the key stream generator employed by the
+arc4 cipher, which uses 8*8 8 bit S-Boxes. The S-Boxes
+can be in about 
+.if t 2\u\s71700\s10\d
+.if n (2**1700)
+states.
+.Pp
+The
+.Fn arc4random_stir
+function reads data from 
+.Pa /dev/urandom
+and uses it to permutate the S-Boxes via
+.Fn arc4random_addrandom .
+.Pp
+There is no need to call 
+.Fn arc4random_stir
+before using
+.Fn arc4random ,
+since
+.Fn arc4random
+automatically initalizes itself.
+.Sh SEE ALSO
+.Xr rand 3 ,
+.Xr random 3 ,
+.Xr srandomdev 3
+.Sh HISTORY
+.Pa RC4 
+has been designed by RSA Data Security, Inc. It was posted anonymously
+to the USENET and was confirmed to be equivalent by several sources who
+had access to the original cipher. Since 
+.Pa RC4
+used to be a trade secret, the cipher is now refered to as 
+.Pa ARC4 .
diff --git a/lib/libc/gen/arc4random.c b/lib/libc/gen/arc4random.c
new file mode 100644
index 000000000000..b9f8a4846832
--- /dev/null
+++ b/lib/libc/gen/arc4random.c
@@ -0,0 +1,172 @@
+/* $Id: arc4random.c,v 1.1 1996/12/28 06:33:01 dm Exp $ */
+
+/*
+ * Arc4 random number generator for OpenBSD.
+ * Copyright 1996 David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project (for instance by leaving this copyright notice
+ * intact).
+ */
+
+/*
+ * This code is derived from section 17.1 of Applied Cryptography,
+ * second edition, which describes a stream cipher allegedly
+ * compatible with RSA Labs "RC4" cipher (the actual description of
+ * which is a trade secret).  The same algorithm is used as a stream
+ * cipher called "arcfour" in Tatu Ylonen's ssh package.
+ *
+ * Here the stream cipher has been modified always to include the time
+ * when initializing the state.  That makes it impossible to
+ * regenerate the same random sequence twice, so this can't be used
+ * for encryption, but will generate good random numbers.
+ *
+ * RC4 is a registered trademark of RSA Laboratories.
+ */
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+struct arc4_stream {
+	u_int8_t i;
+	u_int8_t j;
+	u_int8_t s[256];
+};
+
+static int rs_initialized;
+static struct arc4_stream rs;
+
+static inline void
+arc4_init(as)
+	struct arc4_stream *as;
+{
+	int     n;
+
+	for (n = 0; n < 256; n++)
+		as->s[n] = n;
+	as->i = 0;
+	as->j = 0;
+}
+
+static inline void
+arc4_addrandom(as, dat, datlen)
+	struct arc4_stream *as;
+	u_char *dat;
+	int     datlen;
+{
+	int     n;
+	u_int8_t si;
+
+	as->i--;
+	for (n = 0; n < 256; n++) {
+		as->i = (as->i + 1);
+		si = as->s[as->i];
+		as->j = (as->j + si + dat[n % datlen]);
+		as->s[as->i] = as->s[as->j];
+		as->s[as->j] = si;
+	}
+}
+
+static void
+arc4_stir(as)
+	struct arc4_stream *as;
+{
+	int     fd;
+	struct {
+		struct timeval tv;
+		pid_t pid;
+		u_int8_t rnd[128 - sizeof(struct timeval) - sizeof(pid_t)];
+	}       rdat;
+
+	gettimeofday(&rdat.tv, NULL);
+	rdat.pid = getpid();
+	fd = open("/dev/urandom", O_RDONLY, 0);
+	if (fd >= 0) {
+		(void) read(fd, rdat.rnd, sizeof(rdat.rnd));
+		close(fd);
+	}
+	/* fd < 0?  Ah, what the heck. We'll just take whatever was on the
+	 * stack... */
+
+	arc4_addrandom(as, (void *) &rdat, sizeof(rdat));
+}
+
+static inline u_int8_t
+arc4_getbyte(as)
+	struct arc4_stream *as;
+{
+	u_int8_t si, sj;
+
+	as->i = (as->i + 1);
+	si = as->s[as->i];
+	as->j = (as->j + si);
+	sj = as->s[as->j];
+	as->s[as->i] = sj;
+	as->s[as->j] = si;
+	return (as->s[(si + sj) & 0xff]);
+}
+
+static inline u_int32_t
+arc4_getword(as)
+	struct arc4_stream *as;
+{
+	u_int32_t val;
+	val = arc4_getbyte(as) << 24;
+	val |= arc4_getbyte(as) << 16;
+	val |= arc4_getbyte(as) << 8;
+	val |= arc4_getbyte(as);
+	return val;
+}
+
+void
+arc4random_stir()
+{
+	if (!rs_initialized) {
+		arc4_init(&rs);
+		rs_initialized = 1;
+	}
+	arc4_stir(&rs);
+}
+
+void
+arc4random_addrandom(dat, datlen)
+	u_char *dat;
+	int     datlen;
+{
+	if (!rs_initialized)
+		arc4random_stir();
+	arc4_addrandom(&rs, dat, datlen);
+}
+
+u_int32_t
+arc4random()
+{
+	if (!rs_initialized)
+		arc4random_stir();
+	return arc4_getword(&rs);
+}
+
+#if 0
+/*-------- Test code for i386 --------*/
+#include <stdio.h>
+#include <machine/pctr.h>
+int
+main(int argc, char **argv)
+{
+	const int iter = 1000000;
+	int     i;
+	pctrval v;
+
+	v = rdtsc();
+	for (i = 0; i < iter; i++)
+		arc4random();
+	v = rdtsc() - v;
+	v /= iter;
+
+	printf("%qd cycles\n", v);
+}
+#endif