Entropy Source using RTL-SDR - Revision history

Leo: added tinkering category

2019-09-01T06:24:44Z

added tinkering category

← Older revision		Revision as of 06:24, 1 September 2019
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	{{Navbox Linux}}[[Category:Linux]]		{{Navbox Linux}}[[Category:Linux]]
			[[Category:Tinkering]]

Leo: Text replacement - "Category:Linux{{Navbox Linux}}" to "{{Navbox Linux}}Category:Linux"

2019-09-01T06:22:46Z

Text replacement - "Category:Linux{{Navbox Linux}}" to "{{Navbox Linux}}Category:Linux"

← Older revision		Revision as of 06:22, 1 September 2019
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	* http://sdr.osmocom.org/trac/wiki/rtl-sdr		* http://sdr.osmocom.org/trac/wiki/rtl-sdr

	[[Category:Linux]]~~{{Navbox Linux}}~~		{{Navbox Linux}}[[Category:Linux]]

Leo: Text replacement - "Category:Linux" to "Category:Linux{{Navbox Linux}}"

2019-09-01T05:08:01Z

Text replacement - "Category:Linux" to "Category:Linux{{Navbox Linux}}"

← Older revision		Revision as of 05:08, 1 September 2019
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	* http://sdr.osmocom.org/trac/wiki/rtl-sdr		* http://sdr.osmocom.org/trac/wiki/rtl-sdr

	[[Category:Linux]]		[[Category:Linux]]{{Navbox Linux}}

Leo: Text replacement - "{{highlight|lang=bash" to "{{highlight|lang=terminal"

2017-02-24T04:18:42Z

Text replacement - "{{highlight|lang=bash" to "{{highlight|lang=terminal"

← Older revision		Revision as of 04:18, 24 February 2017
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	Get and compile {{code\|rtl-entropy}}:		Get and compile {{code\|rtl-entropy}}:
	{{highlight\|lang=~~bash~~\|code=		{{highlight\|lang=terminal\|code=
	git clone https://github.com/pwarren/rtl-entropy.git		git clone https://github.com/pwarren/rtl-entropy.git
	cd rtl-entropy		cd rtl-entropy
Line 25:		Line 25:
	{{code\|rtl_entropy}} will by default generate an socket at {{code\|/var/run/rtl_entropy.fifo}}. Use the {{code\|rngd}} to use this socket as an entropy source for {{code\|/dev/random}}. This is accomplished by running:		{{code\|rtl_entropy}} will by default generate an socket at {{code\|/var/run/rtl_entropy.fifo}}. Use the {{code\|rngd}} to use this socket as an entropy source for {{code\|/dev/random}}. This is accomplished by running:

	{{highlight\|lang=~~bash~~\|code=		{{highlight\|lang=terminal\|code=
	rtl_entropy -s 2.4M -e -b		rtl_entropy -s 2.4M -e -b
	rngd -f -r /var/run/rtl_entropy.fifo		rngd -f -r /var/run/rtl_entropy.fifo
Line 62:		Line 62:

	To see the current entropy pool size on your system, run		To see the current entropy pool size on your system, run
	{{highlight\|lang=~~bash~~\|code=		{{highlight\|lang=terminal\|code=
	cat /proc/sys/kernel/random/poolsize		cat /proc/sys/kernel/random/poolsize
	}}		}}

	To see the current entropy bits available, run:		To see the current entropy bits available, run:
	{{highlight\|lang=~~bash~~\|code=		{{highlight\|lang=terminal\|code=
	cat /proc/sys/kernel/random/entropy_avail		cat /proc/sys/kernel/random/entropy_avail
	}}		}}

Leo: /* Creating a Service */

2016-01-07T05:48:31Z

Creating a Service

← Older revision		Revision as of 05:48, 7 January 2016
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	[Service]		[Service]
			ExecStartPre=/usr/bin/mkfifo /var/run/rtl_entropy.fifo
	ExecStart=/usr/bin/rtl_entropy -s 2.4M -o /var/run/rtl_entropy.fifo -e -q 1		ExecStart=/usr/bin/rtl_entropy -s 2.4M -o /var/run/rtl_entropy.fifo -e -q 1

Leo: /* Creating a Service */

2016-01-07T05:30:04Z

Creating a Service

← Older revision		Revision as of 05:30, 7 January 2016
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	== Creating a Service ==		== Creating a Service ==
	To run the utilities above, create or edit the Systemd service file with the following contents.		To run the utilities above, create or edit the Systemd service file with the following contents.

			{{code\|/usr/lib/systemd/system/rtl-entropy.service}}:
			{{highlight\|lang=text\|code=
			[Unit]
			Requires=rngd.service
			Description=RTL Entropy Gatherer Daemon

			[Service]
			ExecStart=/usr/bin/rtl_entropy -s 2.4M -o /var/run/rtl_entropy.fifo -e -q 1

			[Install]
			WantedBy=multi-user.target
			}}

	{{code\|/usr/lib/systemd/system/rngd.service}}:		{{code\|/usr/lib/systemd/system/rngd.service}}:
	{{highlight\|lang=text\|code=		{{highlight\|lang=text\|code=
	[Unit]		[Unit]
	~~Description~~=Description=Hardware RNG Entropy Gatherer Daemon		Requires=rtl-entropy.service
			Description=Hardware RNG Entropy Gatherer Daemon

	[Service]		[Service]
	~~ExecStartPre=/usr/bin/rtl_entropy -s 2.4M -b~~		ExecStart=/sbin/rngd -f -r /var/run/rtl_entropy.fifo
	ExecStart=~~/usr~~/sbin/rngd -f -r /var/run/rtl_entropy.fifo		SuccessExitStatus=66
	~~ExecStopPost~~=~~/usr/bin/killall rtl_entropy~~

	[Install]		[Install]

Leo: service file update

2015-11-23T09:25:39Z

service file update

← Older revision		Revision as of 09:25, 23 November 2015
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	== Creating a Service ==		== Creating a Service ==
	To run the utilities above, create ~~a new~~ Systemd service file with the following contents.		To run the utilities above, create or edit the Systemd service file with the following contents.

	{{code\|/usr/lib/systemd/system/rngd.service}}:		{{code\|/usr/lib/systemd/system/rngd.service}}:
	{{highlight\|lang=text\|code=		{{highlight\|lang=text\|code=
	[Unit]		[Unit]
	Description=~~RTL~~ Entropy		Description=Description=Hardware RNG Entropy Gatherer Daemon

	[Service]		[Service]
	ExecStartPre=/usr/bin/rtl_entropy -s 2.4M -b		ExecStartPre=/usr/bin/rtl_entropy -s 2.4M -b
	ExecStart=/usr/~~bin~~/rngd -f -r /var/run/rtl_entropy.fifo		ExecStart=/usr/sbin/rngd -f -r /var/run/rtl_entropy.fifo
	ExecStopPost=/usr/bin/killall rtl_entropy		ExecStopPost=/usr/bin/killall rtl_entropy

Leo: see also rtl-sdr info

2015-11-23T07:32:44Z

Leo at 05:13, 23 November 2015

2015-11-23T05:13:03Z

← Older revision		Revision as of 05:13, 23 November 2015
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	You can use a cheap RTL-SDR USB dongle as an entropy source for your linux machine using the rtl-entropy project.		You can use a cheap RTL-SDR USB dongle as an entropy source for your linux machine using the [http://rtl-entropy.org/ rtl-entropy project].

	== Installation ==		== Installation ==
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	== See Also ==		== See Also ==
	* https://github.com/pwarren/rtl-entropy		* https://github.com/pwarren/rtl-entropy
			* [[Entropy]]

	[[Category:Linux]]		[[Category:Linux]]

Leo: Created page with "You can use a cheap RTL-SDR USB dongle as an entropy source for your linux machine using the rtl-entropy project. == Installation == Depending on your system, you might not h..."

2015-11-23T05:11:40Z

Created page with "You can use a cheap RTL-SDR USB dongle as an entropy source for your linux machine using the rtl-entropy project. == Installation == Depending on your system, you might not h..."

New page

You can use a cheap RTL-SDR USB dongle as an entropy source for your linux machine using the rtl-entropy project.

== Installation ==
Depending on your system, you might not have the {{code|rtl-entropy}} package. In which case, you will need to compile it manually.

Install the {{code|rng-tools}} package, and also the {{code|rtl-entropy}} dependencies:
* rng-tools
* rtl-sdr-devel
* libcap-devel
* openssl-devel

Get and compile {{code|rtl-entropy}}:
{{highlight|lang=bash|code=
git clone https://github.com/pwarren/rtl-entropy.git
cd rtl-entropy
mkdir build
cd build
cmake ../
make
}}

Run {{code|make install}} or copy the {{code|src/rtl_entropy}} binary to somewhere on the system such as {{code|/usr/bin}}.

== Usage ==
{{code|rtl_entropy}} will by default generate an socket at {{code|/var/run/rtl_entropy.fifo}}. Use the {{code|rngd}} to use this socket as an entropy source for {{code|/dev/random}}. This is accomplished by running:

{{highlight|lang=bash|code=
rtl_entropy -s 2.4M -e -b
rngd -f -r /var/run/rtl_entropy.fifo
}}

=== {{code|rtl_entropy}} Arguments ===
Arguments passed to {{code|rtl_entropy}} are:
{| class="wikitable"
! -s
| sample rate
|-
! -e
| Use Kaminsky debiasing
|-
! -b
| run as a daemon.
|}

Because we are capturing radio, it is possible for an attacker to influence our random pool and possibly any keys generated using this pool. The rtl-entropy developer mentions this on the project's github page and recommends enabling the {{code|-e}} option to turn on Kaminsky debiasing. This in essence makes influencing the entropy pool harder to guess by an attacker.

=== {{code|rngd}} Arguments ===

Arguments passed to {{code|rngd}} are:
{| class="wikitable"
! -f
| Run in the foreground
|-
! -r
| Specify the entropy device
|-
! -W
| The watermark size (defaults to 2048 bits or typically half of the entropy pool size)
|}

The watermark size defines how much influence this device has on the random pool. Setting this too high means the device will dominate the contents of the entropy pool.

To see the current entropy pool size on your system, run
{{highlight|lang=bash|code=
cat /proc/sys/kernel/random/poolsize
}}

To see the current entropy bits available, run:
{{highlight|lang=bash|code=
cat /proc/sys/kernel/random/entropy_avail
}}

== Creating a Service ==
To run the utilities above, create a new Systemd service file with the following contents.

{{code|/usr/lib/systemd/system/rngd.service}}:
{{highlight|lang=text|code=
[Unit]
Description=RTL Entropy

[Service]
ExecStartPre=/usr/bin/rtl_entropy -s 2.4M -b
ExecStart=/usr/bin/rngd -f -r /var/run/rtl_entropy.fifo
ExecStopPost=/usr/bin/killall rtl_entropy

[Install]
WantedBy=multi-user.target
}}

== See Also ==
* https://github.com/pwarren/rtl-entropy

[[Category:Linux]]

← Older revision		Revision as of 07:32, 23 November 2015
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	== See Also ==		== See Also ==
			* [[Entropy]]
	* https://github.com/pwarren/rtl-entropy		* https://github.com/pwarren/rtl-entropy
	* ~~[[Entropy]]~~		* http://sdr.osmocom.org/trac/wiki/rtl-sdr

	[[Category:Linux]]		[[Category:Linux]]