send encrypted secret

[netcriptus]

Allow encrypted secret to be sent on LockedTransfer's metadata

Fixes: #7191

[fredo]

LGTM in general, good job!

Once you have implemented the encryption with the correct public key we are good to go.

2 things to take care/notice:

1. Somewhere deep in my memory I remember that it was not allowed to use an empty (b'0') bytestring as the secret. We should ask some Raiden OGs in the stand up.
2. Some tests that encryption/decryption works would be good.

[istankovic]

@netcriptus nitpick: it would be nice to squash some of the changes (e.g. the pdb stuff, hex encode fix) here and split some others
(like the addition of dependencies in the "refactor tests" commit 26012b3).

[netcriptus]

@netcriptus nitpick: it would be nice to squash some of the changes (e.g. the pdb stuff, hex encode fix) here and split some others
(like the addition of dependencies in the "refactor tests" commit 26012b3).

Will most definitely do it, but sadly I'm not done with this yet. I'm working on more tests. I can promise the squash will come later.

[ezdac]

Some things that need to be addressed.
Also we have to sync with the tsRaiden team again - (the PR could still be merged first)

[fredo]

Looks good to me! thanks

[ezdac]

I discovered a flaw in the serialize-missing mechanism. I'd still rather fix the underlying issue, but possibly we can do that at a later time and merge the PR?
Still, let's discuss briefly in private before merging