What are GPG Tools?
GPG, or GNU Privacy Guard, is a replacement for Symantec’s PGP cryptographic software suite and allows users to encrypt sensitive information. Specifically, GPG Tools includes a utility that integrates with Apple Mail, a GPG Keychain to manage OpenPGP keys, and a command line tool (which I will be using below).
What is Keybase?
Keybase is an identity management service allowing users to manage keys, social media accounts, and devices. The idea is that when you meet someone online and want to exchange secure messages or files with them, you will want some way to establish the other party is who they say they are. Keybase has also created their own file system, which encrypts everything in their mounted drive. It’s a new feature and definitely worth reading more about here.
It’s worth noting that while Keybase does work with GPG and does have a relatively slick CLI, the Keybase CLI does lack equivalents to
gpg --list-keys and
Currently Keybase is in alpha – so that means you need an invite or you can join the wait queue.
Digging Deeper: Key Caveats
Probably obvious data collection, usage, and sharing:
- The information you provide when signing up, i.e. the name you provide, your location, etc., is all stored. The information you put in your profile, including the names of the accounts you choose to verify, are publicly visible.
- Data may be shared to comply with the law after receiving a request via a lawful process.
- Data may be shared as a result of a business transaction, such as a corporate restructuring or merger.
Some potentially less obvious collection, usage, and sharing:
- Usage information is automatically collected and does not appear to be disable…able. So Keybase gathers and stores your IP address, host computer preferences, URL of the site that referred you to the service, how you interacted with the Keybase UI, and how long you were logged in for. This information is stored in logs that "may persist for an indefinite period."
- "We may disclose any information, including your Personal Information and any other information or data collected, stored or processed on our servers, if required to do so by law or in the good-faith belief that such action is necessary…to protect the personal safety of Keybase employees, customers, or the public." I read "good faith" as them asking me to rely on them to Do No Evil with my data, which you may or may not want to do depending on what types of secure information you are interested in sharing.
How to Setup Keybase and GPG
Signup for Keybase with either your invite or when your lucky # is drawn from the queue. When you choose your name, choose with caution. Remember, Keybase is an identity management service, which means that:
- You cannot change your username later, unless you open a new account and delete the old one which brings me to the next point:
- Once a user name is used, it cannot be reused. Even if the account has been deleted.
To clarify #2: this means if you delete your account, the username does not re-enter the free pool. It is unavailable forever. This makes sense, since you wouldn’t want to delete your account and then have someone else come along and pretend to be you. As with all things security: be aware, take care!
Installing Keybase and GPG Tools
You’ll need to install GPG Tools and Keybase. The GPG Tools suite is available on their site for Macs. For Keybase, you can either use the Keybase installer which installs an app and the CLI utility, or you can use Homebrew:
brew install keybase. Note that you may need to run
brew update && brew upgrade keybase. I ultimately used the installer so I could have the app as well to explore later.
Generating your public PGP Key for Keybase
Now that you have your Keybase account and CLI tools, you’ll need to generate a public PGP key so you can encrypt/decrypt files and messages. You can do this either with the Keybase CLI or GPG. In my case, I went the GPG route:
===[ 15:34:05 ]=[ [email protected] ]=[ ~ ]=== $ gpg --gen-key gpg (GnuPG/MacGPG2) 2.0.30; Copyright (C) 2015 Free Software Foundation, Inc. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Please select what kind of key you want: (1) RSA and RSA (default) (2) DSA and Elgamal (3) DSA (sign only) (4) RSA (sign only) Your selection? 1 RSA keys may be between 1024 and 4096 bits long. What keysize do you want? (2048) 4096 Requested keysize is 4096 bits 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) 0 Key does not expire at all Is this correct? (y/N) y GnuPG needs to construct a user ID to identify your key. Real name: Quintessence Email address: myemail[at]example.com Comment: You selected this USER-ID: "Quintessence <myemail[at]example.com>" Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O You need a Passphrase to protect your secret key. We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. gpg: key PSUEDOPUB marked as ultimately trusted public and secret key created and signed. gpg: checking the trustdb gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model gpg: depth: 0 valid: 2 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 2u gpg: next trustdb check due at 2018-08-19 pub 4096R/PSUEDOPUB 2016-08-24 Key fingerprint = <REDACTED> uid [ultimate] Quintessence <myemail[at]example.com> sub 4096R/PSEUDOSUB 2016-08-24 ===[ 15:37:11 ]=[ [email protected] ]=[ ~ ]=== $ gpg --list-keys /Users/quinn/.gnupg/pubring.gpg ------------------------------- pub 2048D/PGPPUB 2010-08-19 [expires: 2018-08-19] uid [ultimate] GPGTools Team <team[at]gpgtools.org> uid [ultimate] GPGMail Project Team (Official OpenPGP Key) <gpgmail-devel[at]lists.gpgmail.org> uid [ultimate] GPGTools Project Team (Official OpenPGP Key) <gpgtools-org[at]lists.gpgtools.org> uid [ultimate] [jpeg image of size 5871] sub 2048g/PGPSUB1 2010-08-19 [expires: 2018-08-19] sub 4096R/PGPSUB2 2014-04-08 [expires: 2024-01-02] pub 4096R/RVMPUB 2014-10-28 uid [ unknown] Michal Papis (RVM signing) <mpapis[at]gmail.com> pub 4096R/PSUEDOPUB 2016-08-24 uid [ultimate] Quintessence <myemail[at]example.com> sub 4096R/PSEUDOSUB 2016-08-24
To export the public key for Keybase:
===[ 15:42:55 ]=[ [email protected] ]=[ ~/.gnupg ]=== $ gpg -a --export PSUEDOPUB -----BEGIN PGP PUBLIC KEY BLOCK----- Comment: GPGTools - https://gpgtools.org ... -----END PGP PUBLIC KEY BLOCK-----
Make sure you use the
-a flag for ASCII, otherwise you’ll get binary output dumping to your terminal. Everyone’s favorite experience, amirite?
Copy/paste the key block into Keybase and choose "command line with
keybase" when prompted for how you would like to sign your public key. Keybase will display the appropriate command to sign the public key, but first you will need to log into the Keybase API on your laptop using the Keybase CLI. To do this, you will use the same password you use to log into the Keybase website. When you initially log in with the Keybase ClI you will be prompted to generate a paper key, as below:
===[ 15:55:57 ]=[ [email protected] ]=[ ~/.gnupg ]=== $ keybase login Your keybase username or email address: quintessence Enter a public name for this device: FingerSkillet =============================== IMPORTANT: PAPER KEY GENERATION =============================== During Keybase's alpha, everyone gets a paper key. This is a private key. 1. you must write it down 2. the first two words are a public label 3. it can be used to recover data 4. it can provision new keys/devices, so put it in your wallet 5. just like any other device, it'll be revokable/replaceable if you lose it Your paper key is <REDACTED> Write it down....now! Have you written down the above paper key? [y/N] y Excellent! Is it in your wallet? [y/N] y ✔ Success! You provisioned your device FingerSkillet. You are logged in as quintessence - type `keybase help` for more info.
Now that you have logged in, you can proceed:
===[ 16:26:00 ]=[ [email protected] ]=[ ~/.gnupg ]=== $ keybase pgp select <REDACTED> # Algo Key Id Created UserId = ==== ====== ======= ====== 1 4096R <REDACTED> Quintessence <myemail[at]example.com> Choose a key: 1 ▶ INFO Bundle unlocked: <REDACTED> ▶ INFO Generated new PGP key: ▶ INFO user: Quintessence <myemail[at]example.com> ▶ INFO 4096-bit RSA key, ID <REDACTED>, created 2016-08-24 ▶ INFO Key <REDACTED> imported
Generating the PGP key with Keybase
The other way to generate your PGP key is with the Keybase CLI, using
keybase pgp gen. When you do, you will be given the option to upload the (encrypted) secret key to Keybase, e.g.:
===[ 14:45:05 ]=[ [email protected] ]=[ ~ ]=== $ keybase pgp gen Enter your real name, which will be publicly visible in your new key: Quintessence Enter a public email address for your key: myemail[at]example.com Enter another email address (or <enter> when done): Push an encrypted copy of your new secret key to the Keybase.io server? [Y/n]
Depending on your level of paranoia, putting a copy of the secret key on the Keybase server might be asking a bit much. Personally, this behavior is a reason in favor of generating keys with
Y is the default action.
Note: When you generate a key with
keybase pgp gen it will appear in your GPG keyring.
Verifying an account with the CLI
Accounts can be verified using either the web UI or using the Keybase CLI. For the latter:
===[ 16:31:42 ]=[ [email protected] ]=[ ~/.gnupg ]=== $ keybase prove github quintessence Please publicly post the following Gist, and name it keybase.md ### Keybase proof I hereby claim: * I am quintessence on github. ... Check Github now? [Y/n] Y ▶ NOTICE Success! ===[ 16:33:46 ]=[ [email protected] ]=[ ~ ]=== $ keybase prove hackernews quintessence Please edit your HackerNews profile to contain the following text. Click here: https://news.ycombinator.com/user?id=quintessence [ my public key: ... Check HackerNews now? [Y/n] Y ▶ NOTICE Success!
Notice when you are proving that you are a user you are proving that you can somehow post as that user. In the case of GitHub, that means creating a public Gist. For other sites, e.g. Twitter and Reddit, you create a tweet/post. An example of a more complete profile is that of one of my coworkers here at S&W, James Hunt:
Following a user
You can see above that
jhunt is already following me on Keybase. If I want to follow him as well, I can do so via the command line using his Keybase username:
===[ 15:27:25 ]=[ [email protected] ]=[ ~ ]=== $ keybase follow jhunt ▶ INFO Identifying jhunt ✔ public key fingerprint: 2BA0 1C9D B438 A64F 214C D2D3 E7B1 C84A EDE5 75A0 ✔ admin of DNS zone jameshunt.us: found TXT entry keybase-site-verification=v_ja_-Bvv9kxVH8l0JKdX_yCTFw4TlsZ2bFXoz4g9M0 ✔ admin of DNS zone niftylogic.com: found TXT entry keybase-site-verification=QQg_TcUz22MGcRgb5DOcBIzsndgBpsuMZmhU7hQ7jes ✔ admin of DNS zone huntprod.com: found TXT entry keybase-site-verification=qfh_K7mBbkb6JP3WrRLyZiu5bWz8jYCyEHwWopfdPDM ✔ "filefrog" on reddit: https://www.reddit.com/r/KeybaseProofs/comments/4trseg/my_keybase_proof_redditfilefrog_keybasejhunt_z9/ ✔ "iamjameshunt" on twitter: https://twitter.com/iamjameshunt/status/755790627552448513 ✔ "jhunt" on github: https://gist.github.com/6347ae03c701d50782f25b879b72c394 Is this the jhunt you wanted? [Y/n] Y Publicly follow? [Y/n] Y
I can now see that he is both following me and I am following him using the Keybase CLI:
===[ 15:59:40 ]=[ [email protected] ]=[ ~ ]=== $ keybase list-followers jhunt ===[ 15:59:46 ]=[ [email protected] ]=[ ~ ]=== $ keybase list-following jhunt
I can also see that I’m following him now using the Keybase web UI:
Why follow other users?
Following users cuts out a couple steps when you wish to send encrypted information. For example, let’s say I wanted to send
jhunt the following message:
keybase encrypt jhunt -m "Check out my blog post!"
If I wasn’t already following
jhunt, the CLI would give me the same manual verification process to ensure that the
jhunt it found was the
jhunt that I intended to encrypt the message for. When I started following
jhunt, Keybase created a signed snapshot of the identity. So now when I encrypt the above message, it uses the signed snapshot instead and doesn’t prompt me to verify the user.
For Keybase, following users also helps establish each user’s web of trust. When I started following
jhunt I verified that I knew him. The more people that follow
jhunt over time lends credibility to the Keybase
jhunt user being matched with the correct person. Keybase talks about this a bit more in their doc on following users.
Keys are removed from the Keybase client using
keybase drop '<KEY>'; however, this does not remove the key from your GPG keyring. Since keys generated with the Keybase CLI are stored in the GPG keyring, regardless of whether you used
gpg to generate the key you will need to revoke the key on the GPG side as well or else the generated key will remain in your GPG keyring.