Install security/gnupg. Enter these lines in ~/.gnupg/gpg.conf to set minimum acceptable defaults for signing and new key preferences (see the GnuPG options documentation for more details):
# Sorted list of preferred algorithms for signing (strongest to weakest). personal-digest-preferences SHA512 SHA384 SHA256 SHA224 # Default preferences for new keys default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 CAMELLIA256 AES192 CAMELLIA192 AES CAMELLIA128 CAST5 BZIP2 ZLIB ZIP Uncompressed
Generate a key:
% gpg --full-gen-key gpg (GnuPG) 2.1.8; 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. Warning: using insecure memory! 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) 2048 (1) Requested keysize is 2048 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) 3y (2) Key expires at Wed Nov 4 17:20:20 2015 MST Is this correct? (y/N) y GnuPG needs to construct a user ID to identify your key. Real name: Chucky Daemon (3) Email address: email@example.com Comment: You selected this USER-ID: "Chucky Daemon <firstname.lastname@example.org>" Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o You need a Passphrase to protect your secret key.
|1||2048-bit keys with a three-year expiration provide adequate protection at present (2022-10).|
|2||A three year key lifespan is short enough to obsolete keys weakened by advancing computer power, but long enough to reduce key management problems.|
|3||Use your real name here, preferably matching that shown on government-issued ID to make it easier for others to verify your identity. Text that may help others identify you can be entered in the |
After the email address is entered, a passphrase is requested. Methods of creating a secure passphrase are contentious. Rather than suggest a single way, here are some links to sites that describe various methods: https://world.std.com/~reinhold/diceware.html, https://www.iusmentis.com/security/passphrasefaq/, https://xkcd.com/936/, https://en.wikipedia.org/wiki/Passphrase.