JEP for X25519/X448 key agreement
adam.petcher at oracle.com
Thu Sep 14 16:59:51 UTC 2017
The JEP for X25519/X448 key agreement is now available and ready to
review. Please take a look and reply with any feedback you have.
The JEP contains a description of the proposed JCA API. We have
discussed the API on this mailing list, and I have attempted to
incorporate all the feedback I have received. Here is a description of
the changes since the last discussion:
1) Multiple people requested more specific types for public/private keys
for this algorithm. The latest API design mirrors the "EC" hierarchy and
has both interfaces and spec classes for public and private keys. I also
added the interface "XDHKey", which serves the same purpose as "ECKey".
2) The representation of public keys was changed from byte to a
BigInteger which holds the u coordinate of the point. Private keys are
still represented using byte due to complications related to pruning,
and also because BigInteger doesn't provide a branch-free way to get the
key into another representation (which is necessary for
The proposed API still lacks a standard way to specify arbitrary domain
parameters, but I believe the API design could be extended to support
this feature. I would prefer to add this API as a separate enhancement
in the future, preferably in cooperation with someone who is developing
a provider that supports this feature.
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