commitments

type Commitment[C any] base.Equatable[C]

type Committer[W Witness, M Message, C Commitment[C]] interface {
	// Commit samples fresh randomness and commits to a message, returning the commitment and witness.
	Commit(message M, prng io.Reader) (C, W, error)
	// CommitWithWitness commits to a message using caller-supplied witness randomness.
	CommitWithWitness(message M, W W) (C, error)
}

type CommitterOption[
	COM Committer[W, M, C], W Witness, M Message, C Commitment[C],
] = func(COM) error

type GenericVerifier[T Committer[W, M, C], W Witness, M Message, C Commitment[C]] struct {
	// contains filtered or unexported fields
}

type GroupHomomorphicScheme[
	K Key,
	W interface {
		Witness
		algebra.HomomorphicLike[W, WT]
	}, WT algebra.UintLike[WT],
	M interface {
		Message
		algebra.HomomorphicLike[M, MT]
	}, MT algebra.UintLike[MT],
	C interface {
		Commitment[C]
		algebra.HomomorphicLike[C, CT]
		algebra.Actable[C, M]
	}, CT algebra.AbelianGroupElement[CT, WT],
	CO Committer[W, M, C], VF Verifier[W, M, C],
	G algebra.AbelianGroup[CT, WT],
] interface {
	HomomorphicScheme[K, W, WT, M, MT, C, CT, CO, VF]
	// Group exposes the group structure.
	Group() G
}

type HomomorphicScheme[
	K Key,
	W interface {
		Witness
		algebra.HomomorphicLike[W, WT]
	}, WT algebra.GroupElement[WT],
	M interface {
		Message
		algebra.HomomorphicLike[M, MT]
	}, MT algebra.GroupElement[MT],
	C interface {
		Commitment[C]
		algebra.HomomorphicLike[C, CT]
		algebra.Actable[C, M]
	}, CT algebra.GroupElement[CT],
	CO Committer[W, M, C], VF Verifier[W, M, C],
] Scheme[K, W, M, C, CO, VF]

type Key any

type Message any

type Name string

type ReRandomisableCommitment[C Commitment[C], W Witness, K Key] interface {
	Commitment[C]
	// ReRandomiseWithWitness re-randomises an existing commitment using caller-supplied witness shift.
	ReRandomiseWithWitness(K, W) (C, error)
	// ReRandomise re-randomises an existing commitment using fresh randomness shift.
	ReRandomise(K, io.Reader) (C, W, error)
}

type Scheme[K Key, W Witness, M Message, C Commitment[C], COM Committer[W, M, C], VF Verifier[W, M, C]] interface {
	// Name returns the identifier of the commitment scheme.
	Name() Name
	// Committer returns a committer configured with the scheme.
	Committer(...CommitterOption[COM, W, M, C]) (COM, error)
	// Verifier returns a verifier compatible with commitments produced by the scheme.
	Verifier(...VerifierOption[VF, W, M, C]) (VF, error)
	// Key exposes the scheme key.
	Key() K
}

type Verifier[W Witness, M Message, C Commitment[C]] interface {
	// Verify checks commitments against provided messages and witnesses.
	Verify(commitment C, message M, witness W) error
}

type VerifierOption[
	VF Verifier[W, M, C], W Witness, M Message, C Commitment[C],
] = func(VF) error

type Witness any