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en:c1_hardware_number_generator [2015/01/29 04:46] mdrjr created |
en:c1_hardware_number_generator [2015/01/29 05:28] (current) mdrjr |
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| + | ====== Introduction ====== | ||
| + | |||
| + | **ODROID-C1** AMLogic S805 has a Hardware Random Number Generator Accelerator! | ||
| + | |||
| + | This entry explains how to enable it and how to test it. | ||
| + | |||
| + | |||
| + | ==== Enabling ==== | ||
| + | Note: You must be running a kernel whose version is **3.10.66-45 or later**. | ||
| + | <code> | ||
| + | sudo apt-get install rng-tools | ||
| + | </code> | ||
| + | |||
| + | That's enough to have the RNGD daemon running. | ||
| + | |||
| + | RNGD is daemon that will check if the kernel needs more entropy and feed that to the kernel when its needed. | ||
| + | |||
| + | When running you'll see something like: | ||
| + | <code> | ||
| + | root@odroid:~# ps xa | grep rng | ||
| + | 968 ? Ss 0:27 /usr/sbin/rngd -r /dev/hwrng | ||
| + | </code> | ||
| + | |||
| + | |||
| + | |||
| + | ==== Testing with and Without ==== | ||
| + | Here we'll see the difference that the hardware generator does. | ||
| + | |||
| + | === Test 1. Without === | ||
| + | |||
| + | 1. We stop the rngd daemon in order to let the kernel/CPU do its job. | ||
| + | <code>sudo /etc/init.d/rng-tools stop</code> | ||
| + | |||
| + | 2. We ask the kernel **10Kbytes** of random data (Remember this number) | ||
| + | <code>sudo dd if=/dev/random of=./random bs=10 count=1024</code> | ||
| + | |||
| + | |||
| + | The output of the command above should be something like: | ||
| + | <code> | ||
| + | root@odroid:~# sudo dd if=/dev/random of=./random bs=10 count=1024 | ||
| + | dd: warning: partial read (8 bytes); suggest iflag=fullblock | ||
| + | 49+975 records in | ||
| + | 49+975 records out | ||
| + | 8290 bytes (8.3 kB) copied, 328.245 s, 0.0 kB/s | ||
| + | root@odroid:~# | ||
| + | </code> | ||
| + | |||
| + | And you can see it took **5 minutes and 28 seconds to read 8290 bytes**. | ||
| + | |||
| + | |||
| + | |||
| + | === Test 2. With HWRNG === | ||
| + | |||
| + | 1. Start the rngd daemon (Previously stopped, not required at every boot) | ||
| + | <code>sudo /etc/init.d/rng-tools start</code> | ||
| + | |||
| + | 2. We ask the kernel for **100Kbytes** of random that. (We request 10K only previously) | ||
| + | Its a increase by 10. | ||
| + | <code>sudo dd if=/dev/random of=./random bs=100 count=1024</code> | ||
| + | |||
| + | The output should be something like: | ||
| + | <code> | ||
| + | root@odroid:~# sudo dd if=/dev/random of=./random bs=100 count=1024 | ||
| + | dd: warning: partial read (25 bytes); suggest iflag=fullblock | ||
| + | 984+40 records in | ||
| + | 984+40 records out | ||
| + | 102175 bytes (102 kB) copied, 0.215086 s, 475 kB/s | ||
| + | </code> | ||
| + | |||
| + | As you can see if took **only 0.21 seconds to get 10 times more data**. | ||
| + | If you request only 10K again it will take only 0.03 seconds. | ||
| + | Even requesting 1Mbyte takes only 3.3 Seconds. | ||
| + | |||
| + | |||
| + | |||
| + | ==== Conclusion ==== | ||
| + | |||
| + | Having the Hardware Random generator off-loads the CPU and increases the amount of "random-ness" to applications that requires it, | ||
| + | such as cryptography. Increase in security and speed on those applications. | ||
