envelope-spec/encoding/tfk.md

specification for envelope encryption

# type-format-key encoding

TFK was the name used for encoding message and feed ids. TFK has now
morphed into a bigger spec for general [binary field encodings] (BFE)
in SSB.

If you came here looking for the tkf.json file, that is now part of
the [ssb-bfe] library.

[binary field encodings]: https://github.com/ssb-ngi-pointer/ssb-binary-field-encodings-spec
[ssb-bfe]: https://github.com/ssb-ngi-pointer/ssb-bfe