Hi Paul,

On Wed, 12 Apr 2023 00:47:46 +0200, me@paulapplegate.com wrote:

When installing Sequoia sq ( v0.29), I checked the version after the install and saw, sq 0.29.0 (sequoia-openpgp 1.14.0, using Nettle 3.8 (Cv448: true)).

`Cv448: true` means that your version of Nettle supports Cv448.

`sq` generates the version string that you quoted above as follows:

``` format!( "{} (sequoia-openpgp {}, using {})", env!("CARGO_PKG_VERSION"), sequoia_openpgp::VERSION, sequoia_openpgp::crypto::backend() ) ```

The documentation for `sequoia_openpgp::crypto::backend` says:

Returns a short, human-readable description of the backend.

This starts with the name of the backend, possibly a version, and any optional features that are available. This is meant for inclusion in version strings to improve bug reports.

https://docs.sequoia-pgp.org/sequoia_openpgp/crypto/fn.backend.html

Nettle's implementation of `backend` is:

``` format!( "Nettle {}.{} (Cv448: {:?})", major, minor, nettle::curve448::IS_SUPPORTED, ) ```

https://gitlab.com/sequoia-pgp/sequoia/-/blob/c1a3ef8c/openpgp/src/crypto/ba...

Not wanting to assume anything, but how does one activate the cv448 ECC curve? I see cv448 mentioned a lot especially in the "justus/ocb" branch. Thanks

That functionality is not part of RFC 4880, but will be part of the upcoming OpenPGP RFC, see e.g.:

https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-08.html#se...

And we'll add that to sequoia-openpgp 2.0.

HTH,

:) Neal