Following are some of my notes and how-tos on creating, and managing PGP keys.

Here is a link to a website with some very good information and best practices for managing keys:
https://help.riseup.net/en/security/message-security/openpgp/best-practices

Most of this article deals with the concept of setting a expiration date on a set of keys to a reasonable time and how you can update that key as time goes by.  Separate to the creation and publishing of your public key, you should set a reminder in whatever calendar system you are using to remind you to update the expiration date BEFORE it does actually expire a couple of weeks ahead of time.  I typically set my keys to expire in 13 months and set my calendar to remind me after 12 or so months.

1) Creating a key set and distributing your public key:

As mentioned, and when prompted, set a reasonable expiration time.  Also create a revocation cert.  See the aforementioned link for details.

- To create a key:
$ gpg2 --gen-key

- List keys:
$ gpg2 --list-keys
/data/home/rchapin/.gnupg/pubring.gpg
-------------------------------------
pub   4096R/E5170CE8 2015-03-26 [expires: 2019-03-14]
uid                  Ryan Chapin <rchapin@nbinteractive.com>
sub   4096R/-------- 2015-03-26 [expires: 2019-03-14]

- Distribute Public Key (use hkps, encrypted connection)
$ gpg2 --keyserver hkps://hkps.pool.sks-keyservers.net --send-keys E5170CE8


2) Searching for keys and verifying that they have been posted to a public keyserver:

- List your keys
$ gpg2 --list-keys
/data/home/rchapin/.gnupg/pubring.gpg
-------------------------------------
pub   4096R/E5170CE8 2015-03-26 [expires: 2019-03-14]
uid                  Ryan Chapin <rchapin@nbinteractive.com>
sub   4096R/-------- 2015-03-26 [expires: 2019-03-14]

The public key for this user is E5170CE8.  The 4096R indicates that it is 4096 bits.

- Searching for the key:
To search for the key via a key server such as https://pgp.mit.edu/ enter the following in the search string

  0xE5170CE8

Make sure to prefix the hex value of the key with 0x to indicate to the keyserver that is a hex value and not an ASCII string.


3) Update the expiration date of a key:

- List the keys:

- List your keys
$ gpg2 --list-keys
/data/home/rchapin/.gnupg/pubring.gpg
-------------------------------------
pub   4096R/E5170CE8 2015-03-26 [expires: 2019-03-14]
uid                  Ryan Chapin <rchapin@nbinteractive.com>
sub   4096R/-------- 2015-03-26 [expires: 2019-03-14]

- Edit the key:
$ gpg2 --edit-key E5170CE8


- Select the key to edit, and then run the expire command.  Select the amount of time afterwhich the key will expire and follow the prompts to enter your passphrase.

gpg> key 0
gpg> expire
Changing expiration time for the primary key.
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 13m
Key expires at Thu 14 Mar 2019 08:42:22 AM EDT
Is this correct? (y/N) y

You need a passphrase to unlock the secret key for
user: "Ryan Chapin <rchapin@nbinteractive.com>"
4096-bit RSA key, ID E5170CE8, created 2015-03-26


- Select the sub-key (1) and repeat the process

- Save the key
gpg> save

- Send the updated key to a keyserver
$ gpg2 --keyserver hkps://hkps.pool.sks-keyservers.net --send-keys E5170CE8

- Or you can export an ASCII-armored PGP key and upload it via a trusted https keyserver.

$ gpg2 --armor --export <your-email-address>

Following is a quick how-to on compiling and adding addition SELinux modules.

When configuring and deploying new and/or custom services on systems that are enforcing SELinux you will likely have to compile addition SELinux modules.

This how-to includes how to go through each step of compiling a new module one-by-one; similar to the model of breaking down the compilation of C and C++ into it's composite steps.

Step 1:  Gather the audit.log entries

You will need to determine which action(s) that SELinux is blocking.  To do so, you can tail the /var/log/audit/audit.log file.  You will see something similar to the following

type=AVC msg=audit(1517605342.101:88032): avc:  denied  { write } for  pid=7236 comm="check_zookeeper" path="/tmp/sh-thd-1517587323" dev="dm-0" ino=308042 scontext=system_u:system_r:nrpe_t:s0 tcontext=system_u:object_r:tmp_t:s0 tclass=file
type=SYSCALL msg=audit(1517605342.101:88032): arch=c000003e syscall=2 success=no exit=-13 a0=1e2df10 a1=2c1 a2=180 a3=0 items=0 ppid=7232 pid=7236 auid=4294967295 uid=997 gid=994 euid=997 suid=997 fsuid=997 egid=994 sgid=994 fsgid=994 tty=(none) ses=4294967295 comm="check_zookeeper" exe="/usr/bin/bash" subj=system_u:system_r:nrpe_t:s0 key=(null)
type=PROCTITLE msg=audit(1517605342.101:88032): proctitle=2F62696E2F62617368002F7573722F6C6F63616C2F6E6167696F732F706C7567696E732F636865636B5F7A6F6F6B65657065722E7368002D2D73746174

Take that output and save it into a file.


Step 2: Generate the Type Enforcement (te) File From the Log Output

audit2allow -m new-module > new-module.te < audit-log-output


Step 3:  Check and Compile the SELinux Security Policy Module (mod) File From the .te File

checkmodule -M -m -o new-module.mod new-module.te


Step 4:  Create the SELinux Policy Module Packet (pp) File From the .mod File

semodule_package -o new-module.pp -m new-module.mod


Step 5:  Install the SELinux Policy Module

semodule -i new-module.pp