* Replace recompute_R with a separate RCompute
This struct can be use to implement verifiers with incremental updates
* Add raw_sign_byupdate and raw_verify_byupdate
These allow signing/verifying a non-prehashed message
but don't require the whole message to be provided at once.
* Tests for raw_sign_byupdate, raw_verify_byupdate
* Add StreamVerifier
* Make StreamVerifier use RCompute
This allows it to use the same implementation as non-stream signature
verification.
* Guard StreamVerifier behind hazmat feature
* docs: disambiguate unsafety
Co-authored-by: Tony Arcieri <bascule@gmail.com>
* chore: relax F bounds on raw_verify_byupdate
* chore: remove raw_sign_byupdate and raw_verify_byupdate
* chore: address clippy lints within new code
* docs: fixup changelog
* test: invert new chunked test
* chore: revert raw_sign
---------
Co-authored-by: Matt Johnston <matt@ucc.asn.au>
Co-authored-by: Tony Arcieri <bascule@gmail.com>
* ed25519-dalek: remove `ExpandedSecretKey::to_bytes`
The reason `ExpandedSecretKey` needs a private `scalar_bytes` field is
to retain the canonical scalar bytes as output by SHA-512 during key
expansion so they can be serialized by the `to_bytes` method.
However, `ExpandedSecretKey`s should not be serialized to the wire.
Removing this method allows the private field to be removed, which
allows `ExpandedSecretKey` to be constructed entirely from public
fields. This provides an alternative to #544 for use cases like
Ed25519-BIP32 where the private scalar is derived rather than clamped
from bytes.
One other change is needed: `to_scalar_bytes` was changed to `to_scalar`
as the canonical scalar bytes are no longer retained, however this has
no impact on its main use case, X25519 Diffie-Hellman exchanges, where
the `Scalar` should NOT be written to the wire anyway.
* Added scalar byte comparison back to ed25519-dalek x25519 test
---------
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
