This channel is created when we open the initial message. It allows us to
seal the initial response at which point the channel gets transformed into a
fully established and bidirectional HPKE channel.
Seal the given plaintext using the associated data and this
UnidirectionalRecipientChannel.
This method will encrypt the given plaintext for the other side of this
channel and fully establish the HPKE channel, enabling bidirectional
communication.
The unidirectional HPKE sender channel.
This channel is created when we open the initial message. It allows us to seal the initial response at which point the channel gets transformed into a fully established and bidirectional HPKE channel.
See HpkeRecipientChannel.establishChannel.