gpg2

GnuPG 2 encryption and digital signatures

TLDR

Generate key pair

$ gpg2 --full-generate-key

List keys

$ gpg2 --list-keys

Encrypt file for recipient

$ gpg2 -e -r [recipient@email.com] [file]

Decrypt file

$ gpg2 -d [file.gpg]

Sign file

$ gpg2 --sign [file]

Verify signature

$ gpg2 --verify [file.sig]

Export public key

$ gpg2 --armor --export [keyid] > [public.asc]

Import a key

$ gpg2 --import [public.asc]

Symmetric encryption with passphrase

$ gpg2 -c [file]

gpg2 (GnuPG 2) is the modern version of GNU Privacy Guard, implementing the OpenPGP standard for encryption, digital signatures, and key management. It uses a modular architecture with separate daemons for improved security.On most modern systems, gpg is aliased to gpg2. The two share keyrings and are functionally equivalent, with gpg2 offering improved architecture and daemon management.

PARAMETERS

-e, --encrypt

Encrypt data.

-d, --decrypt

Decrypt data.

-s, --sign

Sign data.

--verify

Verify signature.

-r, --recipient name

Encrypt for recipient.

-a, --armor

ASCII armored output.

--gen-key

Generate key pair with default settings.

--full-generate-key

Generate key pair with full options (algorithm, size, expiry).

--list-keys

List public keys.

--list-secret-keys

List private keys.

--export keyid

Export public key.

--import file

Import keys.

--delete-keys keyid

Delete public key from keyring.

--delete-secret-keys keyid

Delete secret key from keyring.

--keyserver server

Keyserver to use.

-o, --output file

Write output to file instead of stdout.

--clearsign

Make a cleartext signature.

--detach-sign

Make a detached signature.

-c, --symmetric

Encrypt with a symmetric cipher using a passphrase.

--batch

Run in non-interactive batch mode.

-q, --quiet

Minimize output.

-v, --verbose

Display detailed processing information.

CONFIGURATION

~/.gnupg/gpg.conf

User configuration file for default options, preferred algorithms, and keyserver settings.

~/.gnupg/gpg-agent.conf

Configuration for the gpg-agent daemon handling passphrase caching and key operations.

CAVEATS

Key management requires understanding of web of trust. Private keys must be protected. Passphrase selection is critical. gpg and gpg2 share keyrings on modern systems.

HISTORY

GnuPG was created by Werner Koch in 1997 as a free replacement for PGP. GPG 2.0 was released in 2006 with a modular architecture. It's a fundamental tool for secure email and software signing.