ECC - GnuPG wiki

"Elliptic curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. One of the main benefits in comparison with non-ECC cryptography [...] is the same level of security provided by keys of smaller size.", ECC at Wikipedia, 2015-11-05

Function	Protocol	Curve	OpenPGP specification	Libgcrypt dependency	Token support
Signature	ECDSA	NIST ECC: P-256	RFC6637, RFC4880bis draft		Gnuk >= 1.2.0
Signature	ECDSA	NIST ECC: P-384	RFC6637, RFC4880bis draft
Signature	ECDSA	NIST ECC: P-521	RFC6637, RFC4880bis draft
Signature	ECDSA	ECC Brainpool: brainpoolP256r1	RFC4880bis draft
Signature	ECDSA	ECC Brainpool: brainpoolP384r1
Signature	ECDSA	ECC Brainpool: brainpoolP512r1	RFC4880bis draft
Signature	ECDSA	SECG: secp256k1		libgcrypt >= 1.7.0	Gnuk >= 1.2.0
Signature	EdDSA	RFC8032: Ed25519	RFC4880bis draft		Gnuk >= 1.2.0
Encryption	ECDH	NIST ECC: P-256	RFC6637, RFC4880bis draft		Gnuk >= 1.2.0
Encryption	ECDH	NIST ECC: P-384	RFC6637, RFC4880bis draft
Encryption	ECDH	NIST ECC: P-521	RFC6637, RFC4880bis draft
Encryption	ECDH	ECC Brainpool: brainpoolP256r1	RFC4880bis draft
Encryption	ECDH	ECC Brainpool: brainpoolP384r1
Encryption	ECDH	ECC Brainpool: brainpoolP512r1	RFC4880bis draft
Encryption	ECDH	SECG: secp256k1		libgcrypt >= 1.7.0	Gnuk >= 1.2.0
Encryption	ECDH	RFC7748: Curve25519	RFC4880bis draft	libgcrypt >= 1.7.0	Gnuk >= 1.2.0