diff -urn -- a/miscutils/rng_fips.h b/miscutils/rng_fips.h
--- a/miscutils/rng_fips.h	1970-01-01 00:00:00.000000000 +0000
+++ b/miscutils/rng_fips.h	2008-08-17 13:28:27.000000000 +0000
@@ -0,0 +1,152 @@
+/* vi: set sw=4 ts=4: */
+/* rng_fips.h
+ *
+ * Ported to busybox by Malek Degachi
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#ifndef _RNG_FIPS_H
+#define _RNG_FIPS_H
+
+#include "libbb.h"
+
+/**********************************************
+ * FIPS part
+ *********************************************/
+
+/*  Size of a FIPS test buffer, do not change this */
+#define FIPS_RNG_BUFFER_SIZE 2500
+
+/* Context for running FIPS tests */
+typedef struct {
+	int poker[16];
+	int runs[12];
+	int ones;
+	int rlength;
+	int current_bit;
+	int last_bit;
+	int longrun;
+	unsigned int last32;
+} fips_ctx_t;
+
+/*
+ * Return values for fips_run_rng_test. These values are OR'ed together
+ * for all tests that failed.
+ */
+#define FIPS_RNG_MONOBIT	0x0001 /* FIPS 140-2 2001-10-10 monobit */
+#define FIPS_RNG_POKER		0x0002 /* FIPS 140-2 2001-10-10 poker */
+#define FIPS_RNG_RUNS		0x0004 /* FIPS 140-2 2001-10-10 runs */
+#define FIPS_RNG_LONGRUN	0x0008 /* FIPS 140-2 2001-10-10 long run */
+#define FIPS_RNG_CONTINUOUS_RUN 0x0010 /* FIPS 140-2 continuous run */
+
+/*
+ * fips_test_store - store 8 bits of entropy in FIPS
+ * 			 internal test data pool
+ */
+static void fips_test_store(fips_ctx_t *ctx, unsigned int rng_data)
+{
+	int j;
+
+	ctx->poker[rng_data >> 4]++;
+	ctx->poker[rng_data & 15]++;
+
+	/* Note in the loop below rlength is always one less than the actual
+	   run length. This makes things easier. */
+	for (j = 7; j >= 0; j--) {
+		ctx->ones += ctx->current_bit = ((rng_data >> j) & 1);
+		if (ctx->current_bit != ctx->last_bit) {
+			/* If runlength is 1-6 count it in correct bucket. 0's go in
+			   runs[0-5] 1's go in runs[6-11] hence the 6*current_bit below */
+			if (ctx->rlength < 5) {
+				ctx->runs[ctx->rlength +
+				     (6 * ctx->current_bit)]++;
+			} else {
+				ctx->runs[5 + (6 * ctx->current_bit)]++;
+			}
+
+			/* Check if we just failed longrun test */
+			if (ctx->rlength >= 25)
+				ctx->longrun = 1;
+			ctx->rlength = 0;
+			/* flip the current run type */
+			ctx->last_bit = ctx->current_bit;
+		} else {
+			ctx->rlength++;
+		}
+	}
+}
+
+static int fips_run_rng_test(fips_ctx_t *ctx, const void *buf)
+{
+	int i, j;
+	int rng_test = 0;
+	unsigned char *rngdatabuf;
+
+	if (!ctx) return -1;
+	if (!buf) return -1;
+	rngdatabuf = (unsigned char *)buf;
+
+	for (i=0; i<FIPS_RNG_BUFFER_SIZE; i += 4) {
+		int new32 = rngdatabuf[i] | 
+			    ( rngdatabuf[i+1] << 8 ) | 
+			    ( rngdatabuf[i+2] << 16 ) | 
+			    ( rngdatabuf[i+3] << 24 );
+		if (new32 == ctx->last32) rng_test |= FIPS_RNG_CONTINUOUS_RUN;
+		ctx->last32 = new32;
+		fips_test_store(ctx, rngdatabuf[i]);
+		fips_test_store(ctx, rngdatabuf[i+1]);
+		fips_test_store(ctx, rngdatabuf[i+2]);
+		fips_test_store(ctx, rngdatabuf[i+3]);
+	}
+
+	/* add in the last (possibly incomplete) run */
+	if (ctx->rlength < 5)
+		ctx->runs[ctx->rlength + (6 * ctx->current_bit)]++;
+	else {
+		ctx->runs[5 + (6 * ctx->current_bit)]++;
+		if (ctx->rlength >= 25)
+			rng_test |= FIPS_RNG_LONGRUN;
+	}
+	
+	if (ctx->longrun) {
+		rng_test |= FIPS_RNG_LONGRUN;
+		ctx->longrun = 0;
+	}
+
+	/* Ones test */
+	if ((ctx->ones >= 10275) || (ctx->ones <= 9725))
+		rng_test |= FIPS_RNG_MONOBIT;
+	/* Poker calcs */
+	for (i = 0, j = 0; i < 16; i++)
+		j += ctx->poker[i] * ctx->poker[i];
+	/* 16/5000*1563176-5000 = 2.1632  */
+	/* 16/5000*1576928-5000 = 46.1696 */
+	if ((j > 1576928) || (j < 1563176))
+		rng_test |= FIPS_RNG_POKER;
+
+	if ((ctx->runs[0] < 2315) || (ctx->runs[0] > 2685) ||
+	    (ctx->runs[1] < 1114) || (ctx->runs[1] > 1386) ||
+	    (ctx->runs[2] < 527) || (ctx->runs[2] > 723) ||
+	    (ctx->runs[3] < 240) || (ctx->runs[3] > 384) ||
+	    (ctx->runs[4] < 103) || (ctx->runs[4] > 209) ||
+	    (ctx->runs[5] < 103) || (ctx->runs[5] > 209) ||
+	    (ctx->runs[6] < 2315) || (ctx->runs[6] > 2685) ||
+	    (ctx->runs[7] < 1114) || (ctx->runs[7] > 1386) ||
+	    (ctx->runs[8] < 527) || (ctx->runs[8] > 723) ||
+	    (ctx->runs[9] < 240) || (ctx->runs[9] > 384) ||
+	    (ctx->runs[10] < 103) || (ctx->runs[10] > 209) ||
+	    (ctx->runs[11] < 103) || (ctx->runs[11] > 209)) {
+		rng_test |= FIPS_RNG_RUNS;
+	}
+	
+	/* finally, clear out FIPS variables for start of next run */
+	memset(ctx->poker, 0, sizeof (ctx->poker));
+	memset(ctx->runs, 0, sizeof (ctx->runs));
+	ctx->ones = 0;
+	ctx->rlength = -1;
+	ctx->current_bit = 0;
+
+	return rng_test;
+}
+#endif /* _RNG_FIPS_H */
diff -urn -- a/miscutils/rngd.c b/miscutils/rngd.c
--- a/miscutils/rngd.c	2021-04-14 10:06:59.131381906 +0300
+++ b/miscutils/rngd.c	2021-04-14 10:04:59.785401231 +0300
@@ -0,0 +1,193 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * rngd implementation for busybox
+ *
+ * Ported to busybox by Malek Degachi
+ *
+ * Licensed under GPLv2 or later, see file License in this tarball for details.
+ *
+ */
+
+//config:config RNGD
+//config:	bool "rngd"
+//config:	default n
+//config:	help
+//config:	Hardware random number generation daemon.
+//config:config FEATURE_RNGD_LONG_OPTIONS
+//config:	bool "Enable long options"
+//config:	default n
+//config:	depends on RNGD && GETOPT_LONG
+//config:	help
+//config:	Support long options for the rngd applet.
+
+//applet:IF_RNGD(APPLET(rngd, BB_DIR_USR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_RNGD) += rngd.o
+
+//usage:#define rngd_trivial_usage
+//usage:       "[-bf] [-o random file] [-r rng file] [-s step] [-t nnn] [-W n]"
+//usage:#define rngd_full_usage "\n\n"
+//usage:       "Check and feed random data from hardware device to kernel entropy pool.\n"
+//usage:      "\nOptions:"
+//usage:     "\n	-b,--background		Become a daemon (default)"
+//usage:     "\n	-f,--foreground		Do not fork and become a daemon"
+//usage:     "\n	-o,--rng-device=file	Kernel device used for random number output"
+//usage:     "\n				(default: /dev/random)"
+//usage:     "\n	-r,--random-step=nnn	Kernel device used for random number input"
+//usage:     "\n				(default: /dev/hw_random)"
+//usage:     "\n	-s,--random-step=nnn	Number of bytes written to random-device at a time"
+//usage:     "\n				(default: 64)"
+//usage:     "\n	-t,--timeout=nnn	Interval written to random-device when the entropy"
+//usage:     "\n				pool is full, in seconds (default: 60)"
+//usage:     "\n	-W,--fill-watermark=n	Do not stop feeding entropy to random-device until"
+//usage:     "\n				at least n bits of entropy are available in the"
+//usage:     "\n				pool (default: 2048), 0 <= n <= 4096"
+
+
+#include "libbb.h"
+#include "rng_fips.h"
+#include <syslog.h>
+
+#ifndef __u32
+typedef unsigned int __u32;
+#endif
+#include <linux/random.h>	/* struct rand_pool_info, RNDADDENTROPY and RNDGETENTCNT */
+
+enum {
+	RNG_b	= (1 << 0),
+	RNG_f	= (1 << 1),
+	RNG_o	= (1 << 2),
+	RNG_r	= (1 << 3),
+	RNG_s	= (1 << 4),
+	RNG_t	= (1 << 5),
+	RNG_W	= (1 << 6),
+};
+
+static void random_add_entropy(int random_fd, void *buf, size_t size)
+{
+	struct rand_pool_info *entropy;
+
+	entropy = xmalloc(sizeof(struct rand_pool_info) + size);
+
+	entropy->entropy_count = size * 8;
+	entropy->buf_size = size;
+	memcpy(entropy->buf, buf, size);
+
+	ioctl_or_perror_and_die(random_fd, RNDADDENTROPY, entropy, "RNDADDENTROPY failed: %s\n",
+			strerror(errno));
+}
+
+static void random_sleep(int random_fd, double timeout, unsigned fill_watermark)
+{
+	int ent_count;
+	struct pollfd pfd[1];
+
+	pfd[0].fd = random_fd;
+	pfd[0].events = POLLOUT;
+
+	ioctl_or_perror_and_die(random_fd, RNDGETENTCNT, &ent_count, "RNDGETENTCNT failed: %s\n",
+			strerror(errno));
+	if (ent_count < fill_watermark) return;
+	
+	safe_poll(pfd, 1, 1000.0 * timeout);
+}
+
+/* Initialize entropy source */
+static int discard_initial_data(int rng_fd)
+{
+	/* Trash 32 bits of what is probably stale (non-random)
+	 * initial state from the RNG.  For Intel's, 8 bits would
+	 * be enough, but since AMD's generates 32 bits at a time...
+	 *
+	 * The kernel drivers should be doing this at device powerup,
+	 * but at least up to 2.4.24, it doesn't. */
+	unsigned char tempbuf[4];
+
+	xread(rng_fd, tempbuf, sizeof tempbuf);
+
+	/* Return 32 bits of bootstrap data */
+	xread(rng_fd, tempbuf, sizeof tempbuf);
+
+	return tempbuf[0] | (tempbuf[1] << 8) | 
+		(tempbuf[2] << 16) | (tempbuf[3] << 24);
+}
+
+
+#if ENABLE_FEATURE_RNGD_LONG_OPTIONS
+static const char rngd_longopts[] ALIGN1 =
+	"background\0"		No_argument		"b"
+	"foreground\0"		No_argument		"f"
+	"random-device\0"	Required_argument	"o"
+	"rng-device\0"		Required_argument	"r"
+	"random-step\0"		Required_argument	"s"
+	"timeout\0"		Required_argument	"t"
+	"fill-watermark\0"	Required_argument	"W"
+	;
+#endif
+
+int rngd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int rngd_main(int argc UNUSED_PARAM, char **argv)
+{
+	const char *random_name = "/dev/random";
+	const char *rng_name = "/dev/hw_random";
+	int random_step = 64;
+	unsigned fill_watermark;
+	double poll_timeout = 60;
+
+	const char *watermark = "2048";
+	static int rng_fd;
+	static int random_fd;
+
+	unsigned char buf[FIPS_RNG_BUFFER_SIZE];
+	unsigned char *p;
+	int fips;
+	fips_ctx_t *fipsctx;
+
+#if ENABLE_FEATURE_RNGD_LONG_OPTIONS
+	applet_long_options = rngd_longopts;
+#endif
+
+
+	getopt32(argv, "bfo:r:s:t:W:", &random_name, &rng_name, &random_step, &poll_timeout, &watermark);
+	argv += optind;
+
+	fill_watermark = xatou_range(watermark, 0, 4096);
+
+	/* Init entropy source, and open hardware RNG device */
+	rng_fd = xopen(rng_name, O_RDONLY);
+
+	/* Bootstrap FIPS tests */
+	fipsctx = (fips_ctx_t *) xzalloc(sizeof(fips_ctx_t));
+	fipsctx->rlength = -1;
+	fipsctx->last32 = discard_initial_data(rng_fd);
+
+	/* Init entropy sink and open random device */
+	random_fd = xopen(random_name, O_RDWR);
+
+	if (!(option_mask32 & RNG_f)) { /* no -f */
+		bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
+		openlog(applet_name, LOG_PID, LOG_DAEMON);
+		logmode = LOGMODE_SYSLOG;
+	}
+
+	write_pidfile("/var/run/rngd.pid");
+	for (;;) {
+		xread(rng_fd, buf, sizeof buf);
+
+		fips = fips_run_rng_test(fipsctx, buf);
+
+		if (fips) {
+			bb_info_msg("failed fips test");
+			sleep(1);
+			continue;
+		}
+
+		for (p = buf; p + random_step <= &buf[sizeof buf]; p += random_step) {
+			random_add_entropy(random_fd, p, random_step);
+			random_sleep(random_fd, poll_timeout ? : -1.0, fill_watermark);
+		}
+	}
+
+	return EXIT_SUCCESS;
+}
+