export to ssh

[pmazzini]

Initial support for exporting keys in the SSH format as requested in #111.
For now it only supports Ed25519 curves but it shouldn't be hard to add additional ones.

[tomato42]

IIRC, openssh supports only 4 or 5 curves (P-256, P-384, P-521, Ed25519, Ed448), I see no reason not to support all of them...

[tomato42]

test coverage missing

[beldmit]

IIRC, openssh supports only 4 or 5 curves (P-256, P-384, P-521, Ed25519, Ed448), I see no reason not to support all of them...

Not sure about Ed448

[pmazzini]

test coverage missing

I am happy to add some tests if you think the code is looking ok-ish.

[pmazzini]

Not sure about Ed448

Yeah, there is no support for Ed448 yet.

[tomato42]

test coverage missing

I am happy to add some tests if you think the code is looking ok-ish.

yes, the code looks ok-ish, but python 2.6 compat and test coverage is mandatory, I won't merge the code otherwise.

[pmazzini]

Added unit tests. CI for Py 2.x was working fine.

[tomato42]

you will need to use methods from https://github.com/tlsfuzzer/python-ecdsa/blob/master/src/ecdsa/_compat.py for py2 compat

[tomato42]

CI failures are relevant

[pmazzini]

Switched to compat int_to_bytes.

[tomato42]

CI failures on Python 2 still.

Also, please note the code checks run: https://github.com/tlsfuzzer/python-ecdsa/actions/runs/6374029084/job/17310264458?pr=323

[pmazzini]

Switch to using der.topem() and fix it while on it.
Use a line break every 76 bytes: https://docs.python.org/3/library/base64.html#base64.encodebytes

[pmazzini]

Use compat26_str in der.topem().

[pmazzini]

More compat26_str.

[pmazzini]

Fix typo.

[pmazzini]

Any blocker for merging? :)

[tomato42]

Any blocker for merging? :)

yes, my time to do a final review :)

thanks for the PR!