- Revocation tickets are now created by default.
- Secring.gpg will no longer store secret keys (About Damn time)
- Support for ECC.
A few things that make support for ECC very peculiar in the 2.1 release.
"For many people the NIST and also the Brainpool curves have an doubtful origin and thus the plan for GnuPG is to use Bernstein’s Curve 25519 as default. GnuPG 2.1.0 already comes with support for signing keys using the Ed25519 variant of this curve. This has not yet been standardized by the IETF (i.e. there is no RFC) but we won’t wait any longer and go ahead using the proposed format for this signing algorithm. The format for an encryption key has not yet been finalized and will be added to GnuPG in one of the next point releases."
$ gpg2 --expert --full-gen-key gpg (GnuPG) 2.1.0; Copyright (C) 2014 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) (7) DSA (set your own capabilities) (8) RSA (set your own capabilities) (9) ECC and ECC (10) ECC (sign only) (11) ECC (set your own capabilities) Your selection? 9 Please select which elliptic curve you want: (2) NIST P-256 (3) NIST P-384 (4) NIST P-521 (5) Brainpool P-256 (6) Brainpool P-384 (7) Brainpool P-512 Your selection? 2 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) Key does not expire at all Is this correct? (y/N) y GnuPG needs to construct a user ID to identify your key.
These slides make a good case for the dangers of ECC.
I would personally Stay away from ECC in GNUPG until they have curve 25519 available
for processes other than signing messages.