With my current OpenPGP key set to expire in the middle of December I’ve decided to extend its life by changing the expiry date for the primary signing key 0xFEEEFA8F and adding a new encryption subkey that can be used when the existing one expires. The new expiry date for the main signing key as well as the new encryption subkey is 2 years from today. Before getting into the actual notice allow me to capture exactly what I did:
Recently there have been two very good, and opposing, articles written on the state of Pretty Good Privacy (PGP) and whether or not it is worth using in 2016/2017 and beyond. You can find the original article, I’m throwing in the towel on PGP, and I work in security, at Ars Technica here but I’ve reproduced it below in case the link stops working at some point. You can also find the follow up piece, Why I’m not giving up on PGP, also at Ars Technica here and again I’ve reproduced it below just in case.
If you are worried about your hard drive one day crashing and you losing access to your OpenPGP key (and thus the contents of your encrypted e-mails) then you should have been using a backup! That said an extra archival method of storing your key completely offline would be to use a program called paperkey to export the contents of your OpenPGP key to an easily printed file that you can then re-type into your PC if necessary.
While I am by no means a security expert the following are the current best practices for configuring your gpg.conf file as best as I can determine. Key usage options default-key <your primary key> Use as the default key to sign with. If this option is not used, the default key is the first key found in the secret keyring. hidden-encrypt-to <your primary key> Same as –hidden-recipient but this one is intended for use in the options file and may be used with your own user-id as a hidden “encrypt-to-self”.
As advances in cryptography and technology move forward there is a chance that your once secure system may suddenly be relying on outdated (and perhaps now broken) algorithms or implementations. Some good examples of this in recent memory are the breaking of the MD5 hash algorithm and the constant problems plaguing the RC4 encryption cipher. When it comes to PGP it is well known that short keys, keys generated without good entropy to pull from or keys using outdated implementations and algorithms can be far less secure than you would hope they would be.
I recently came across a very good (albeit sort of old) post over at Chris Wellons’ null program blog about increasing the default protections on your stored PGP key. The short hand version is that gpg attempts to protect your PGP key from theft by encrypting it on disk so that if anyone gets access to your secret key file they still don’t immediately have access to your PGP key.
Came across pgp.asc a while back but finally got around to setting it up here. What is pgp.asc? From their website: What is pgp.asc? pgp.asc is an initiative to decentralize public PGP keys, making it easier to get an up to date and authenticated key. Sounds complicated? It isn’t: Just upload your public PGP key to your websites root folder and you’re good to go! So there you have it.
If you’ve had issues trying to get Thunderbird to send your PGP signed e-mail using anything other than SHA-1 there is a quick and easy fix that will let you pick whichever hash you prefer. Open up Thunderbird’s preferences On the Advanced Tab, under General click Config Editor… In the about:config window search for “extensions.enigmail.mimeHashAlgorithm” without quotes. Double click on this and enter a value.
After reading this I’m still not 100% sure there can ever be a completely “safe” way to do this with Twitter. That said some ways are certainly better than others… Personally I think the best of the approaches listed is to include the full key fingerprint and then to also periodically tweet the details. At least that way if an attacker does go and maliciously modify your bio there is still a chance for someone to see the good tweet as well.
Below you will find my OpenPGP Key Transition notice signaling my intention to migrate from my current key (0x1CD3E3D8) to my new one (0xFEEEFA8F). Note that it is very likely that the software used on this website will render the notice in such a way as to invalidate the signature below. Instead please see the plain text version here to do proper validation against or check out my About Me page for full details.