Bug 3087

Summary: Ed448 support
Product: Portable OpenSSH Reporter: sergio <sergio+it>
Component: MiscellaneousAssignee: Assigned to nobody <unassigned-bugs>
Status: REOPENED ---    
Severity: enhancement CC: complain, djm, git, mindrot
Priority: P5    
Version: 8.1p1   
Hardware: Other   
OS: Linux   

Description sergio 2019-11-03 18:41:16 AEDT
Please add support for Ed448 keys.
Comment 1 Damien Miller 2020-01-25 16:25:44 AEDT
Sorry, we don't see any need for ed448. There's nothing wrong with the algorithm per se, but there doesn't seem to be much point for it. Being able to break ed25519 seems to require either a fundamental cryptanalytic result against elliptic curve cryptography or quantum computation.

In either case, the attack that allows ed25519 to be broken is likely to apply equally to ed448. I.e. if one falls, then the other is almost certainly going to as well.
Comment 2 sergio 2020-02-13 03:57:45 AEDT
Quite an odd decision. ed448 differs from ed25519 same as rsa4096 from rsa8192. It's not about quantum computation resistance but about a key length. Moreover ed448 is included into multiple RFCs and supported in openssl for example.
Comment 3 sergio 2020-08-06 20:46:50 AEST
I believe this decision should be reviewed.
Comment 4 sergio 2020-08-06 20:49:12 AEST
openssl supports Ed448
gnupg will support Ed448: https://dev.gnupg.org/D505
erlang ssh supports Ed448: https://erlang.org/doc/man/SSH_app.html
Comment 5 complain 2020-10-13 05:39:31 AEDT
For completeness it should be noted that since this bug was closed, ssh-ed448 was formalized in RFC 8709:

https://tools.ietf.org/rfc/rfc8709.txt
Comment 6 Christian Kujau 2021-11-16 01:20:57 AEDT
Adding more and more software that supports Ed448 may look a bit spammy, but I cannot resist doing exactly that:
 
Putty supports Ed448 keys since v0.75 (released 2021-05-08)
https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/ed448.html

Thanks for re-considering :-)