gpg --quick-gen-key myName

duplicity --encrypt-key myName some-directory file://backup

===== Begin GnuPG log =====
gpg: ebncrypted with 1024-bit RSA key, ID FA5B21B4E274D59A, created 2019-08-14 "myName"
gpg: public key decryption failed: No passphrase given
gpg: decryption failed: No secret key
===== End GnuPG log =====