Add option to retrieve additionaly entropy from YubiKey itself

pull/209/head
Mirko Vogt 2020-08-29 16:15:36 +00:00
parent 697a7d8fb9
commit 767b84eb3b
1 changed files with 13 additions and 0 deletions

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@ -320,6 +320,18 @@ $ cat /proc/sys/kernel/random/entropy_avail
Most operating systems use software-based pseudorandom number generators. A hardware random number generator like [OneRNG](https://onerng.info/onerng/) will [increase the speed](https://lwn.net/Articles/648550/) of entropy generation and possibly the quality.
From YubiKey firmware version 5.2.3 onwards - which introduces "Enhancements to OpenPGP 3.4 Support" - we can gather additional entropy from the YubiKey itself via the SmartCard interface.
## YubiKey
To feed the system's PRNG with entropy generated by the YubiKey itself, issue:
```console
$ echo "SCD RANDOM 512" | gpg-connect-agent | sudo tee /dev/random | hexdump -C
```
This will seed the Linux kernel's PRNG with additional 512 bytes retrieved from the YubiKey.
## OneRNG
Install and configure OneRNG software:
```console
@ -2447,3 +2459,4 @@ Admin PIN: 12345678
* https://www.void.gr/kargig/blog/2013/12/02/creating-a-new-gpg-key-with-subkeys/
* https://mlohr.com/gpg-agent-forwarding/
* https://www.ingby.com/?p=293
* https://support.yubico.com/support/solutions/articles/15000027139-yubikey-5-2-3-enhancements-to-openpgp-3-4-support