Ed25519 & ECC support

[ctrlcctrlv]

ECC keys were recently added to GnuPG, and various RFCs are open or accepted for it:

https://www.gnupg.org/faq/whats-new-in-2.1.html
https://www.ietf.org/id/draft-koch-eddsa-for-openpgp-03.txt
https://www.gnupg.org/documentation/manuals/gcrypt/ECC-key-parameters.html#ECC-key-parameters
https://tools.ietf.org/html/rfc6637
https://www.ietf.org/mail-archive/web/openpgp/current/msg07321.html

However, openpgp-php doesn't support ECC keys. I've been trying to add it myself, but it's quite difficult. I'm not sure what key fields I should use, for example.

Anyone have any ideas or want to take a crack at it? ECC keys are awesome and super useful.

[singpolyma]

Do you have a PHP library for ECC that you're using?

[ctrlcctrlv]

Yep, libsodium-php, but I want to make it so that people can export their keys in GnuPG format.

[Rotzbua]

You can use openssl for encryption and signing. Of course you need a modern openssl version which support ecc.

[Mikiya83]

Any news about ECC support ?
Thanks

[sartor]

I need this feature too

[Rotzbua]

@sartor Then implement it and create a pr.

[mpdude]

Could anyone give some starting pointers what would be needed for this extension? In particular for adding the necessary import/export formats (“packet” in GPG speak?), when libsodium would be used for the heavy lifting parts?

[mpdude]

@singpolyma do you think you could give some starting pointers what needs to be done for this?

[singpolyma]

I have put in the extensions needed for ECDH, ECDSA, and EdDSA key parsing, serialization, and fingerprint calculation 3b62407

[singpolyma]

Support for verifying Ed25519 signatures: fe63af6

[singpolyma]

sodium will not be able to support the full range of OpenPGP ECC options, since it is limited to 25519 curve, but it's a start

[mpdude]

😮

🕺🏼 Thank you @singpolyma!

Now I will have to learn how to use it.

My goal is writing a pure-PHP CLI that can be used by Git instead of a full GPG implementation, and just for signing.

Maybe that can lower the barrier for PHP devs to start signing their Git commits.

[Rotzbua]

@mpdude As mentioned in #13 (comment) just use openssl. I already implemented it years ago. Unfortunately the code is lost 😢 and the only thing I remember that I used normal openssl for the ecc crypto part. Good luck 🚀