veto, curve: Added an abstraction layer for elliptic curves

This will allow to easily swap various curves and implementations, for benchmarking, f.e.

1 files changed, 61 insertions, 0 deletions

diff --git a/curve/curve.go b/curve/curve.go
new file mode 100644
index 0000000..a194cde
--- /dev/null
+++ b/curve/curve.go
@@ -0,0 +1,61 @@
+// This package implements an abstraction for various
+// elliptic curve primitives, as multiplicative group.
+package curve
+
+import "io"
+
+type Data interface {
+	Bytes() []byte
+	String() string
+}
+
+type SomeScalar[S Data] interface {
+	Add(S) S
+	Sub(S) S
+	Mult(S) S
+	Equal(S) bool
+
+	// Maybe later:
+	// Invert(S) S
+	// Negate(S) S
+}
+
+type ScalarReader[S any] interface {
+	RandomScalar() S
+	ScalarFromReader(io.Reader) (S, error)
+	ScalarFromBytes([]byte) (S, error)
+}
+
+type MultiplicativeCurve[S SomeScalar[s], s Data, P MPoint[S, s, p], p Data] interface {
+	ScalarReader[S]
+
+	Identity() P
+	Generator() P
+	Product([]P) P
+	Exp(S) P
+}
+
+type MPoint[S SomeScalar[s], s Data, P Data] interface {
+	Mult(P) P
+	Div(P) P
+	Inv() P
+	Exp(S) P
+	Equal(P) bool
+}
+
+// For additive formulation of the curve, use these interfaces:
+type AdditiveCurve[S SomeScalar[s], s Data, P APoint[S, s, p], p Data] interface {
+	ScalarReader[S]
+	Zero() P
+	Generator() P
+	Sum([]P) P
+	Mul(S) P
+}
+
+type APoint[S SomeScalar[s], s Data, P Data] interface {
+	Add(P) P
+	Sub(P) P
+	Neg(P) P
+	ScalarMult(S) P
+	Equal(P) bool
+}
\ No newline at end of file