sign.mpcl

// -*- go -*-

// This example implements Ed25519 signature computation. The Ed25519
// keypair is:
//
//	pub  : 8ae64963506002e267a59665e9a2e6f9348cc159be53747894478e182ece9fcb
//
//	priv : 2f8d55706c0cb226d75aafe2f4c4648e5cd32bd51fbc9764d54908c67812aee2
//	       8ae64963506002e267a59665e9a2e6f9348cc159be53747894478e182ece9fcb
//
// The Garbler and Evaluator share the private key as two random
// shares. The private key is contructed during the signature
// computation by XOR:ing the random shares together:
//
//	privG: a66e6bb15b6ad6b19bacf163573d0179de7f62bafcd6aba521d525a0d7b79f7e
//	       153801bc47f6d566a274e370f615f140f20202ab80ec88fdd611b726b8526726
//
//
//	privE: 89e33ec1376664974cf65e81a3f965f782ac496fe36a3cc1f49c2d66afa5319c
//	       9fde48df1796d784c5d175151fb717b9c68ec3f23ebffc854256393e969cf8ed
//
//	priv = privG ^ privE
//
// Run the Evaluator with one input: the Evaluator's private key share:
//
//	./garbled -e -v -stream -i 0x89e33ec1376664974cf65e81a3f965f782ac496fe36a3cc1f49c2d66afa5319c9fde48df1796d784c5d175151fb717b9c68ec3f23ebffc854256393e969cf8ed
//
// The Garbler takes two inputs: the message to sign, and the
// Garbler's private key share:
//
//	./garbled -stream -v -i 0x4d61726b6b7520526f737369203c6d747240696b692e66693e2068747470733a2f2f7777772e6d61726b6b75726f7373692e636f6d2f,0xa66e6bb15b6ad6b19bacf163573d0179de7f62bafcd6aba521d525a0d7b79f7e153801bc47f6d566a274e370f615f140f20202ab80ec88fdd611b726b8526726 examples/ed25519/sign.mpcl
//
// The result signature is:
//
//	Result[0]: f43c1cf1755345852211942af0838414334eec9cbf36e26a9f9e8d4bb720deb145ffbeec82249c875116757441206bcdc56b501e750f1f590917d772dfee980f
package main

import (
	"crypto/ed25519"
)

type Garbler struct {
	msg       [64]byte
	privShare [64]byte
}

func main(g Garbler, privShare [64]byte) []byte {
	var priv [64]byte

	for i := 0; i < len(priv); i++ {
		priv[i] = g.privShare[i] ^ privShare[i]
	}

	return ed25519.Sign(priv, g.msg)
}