Also use fully secure ChaChaRng with a full seed, not just a u64.
Now that we always generate an extra proper VerificationKey for each
Tweak::ChangePubkey case, this /should/ never fail: it also helps split out the
actual verification of the signature from the parsing and validation of the key
itself.
* Impl DefaultIsZeros for every type that uses jubjub::Fr/Scalar
This requires Copy and Clone along with Default. If we do not want to include those, we can impl Zeroize and Drop directly.
* Hash signature message with HStar before deriving the binding factor
To avoid a collision, we should hash our input message, our 'standard' hash is HStar, which uses a domain separator already, and is the same one that generates the binding factor.
* Add a comment about why we hash the signature message before generating the binding factor
* Add comments on how we Zeroize
* Consume nonces with sign()
We want to make sure that the nonces we use when signing are Drop'd
(and thus Zeroize'd) when they go out of scope, so we must move participant_nonces into sign()
Implements FROST (Flexible Round Optimized Schnorr Threshold Signatures, https://eprint.iacr.org/2020/852) where key generation is performed by a trusted dealer.
Future work will include implementing distributed key generation and re-randomizability.
Co-authored-by: Chelsea Komlo <me@chelseakomlo.com>
Co-authored-by: Isis Lovecruft <isis@patternsinthevoid.net>
This closes a gap in the API where it was impossible to retry items in a failed
batch, because the opaque Item type could not be verified individually.
* Pulls in some traits and methods from curve25519-dalek around the
vartime multiscalar multiplication.
* Move scalar mul things we want to upstream to jubjub to their own crate
* Make Verify agnostic to the SigType
Co-authored-by: Henry de Valence <hdevalence@hdevalence.ca>
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
The `SpendAuth` test vectors were generated using
`FixedGenerators::SpendingKeyGenerator`, and the `Binding` test vectors
were generated using `FixedGenerators::ValueCommitmentRandomness`.
Deirdre Connolly
Alfredo Garcia
Deirdre Connolly
Marek
Jack Grigg
Henry de Valence