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tecdsa/dklsv1/dealer/dealer.go

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+//
+// Copyright Coinbase, Inc. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+// Package dealer implements key generation via a trusted dealer for the protocol [DKLs18](https://eprint.iacr.org/2018/499.pdf).
+// The trusted dealer produces the same output as the corresponding DKG protocol and can be used for signing without
+// additional modifications.
+// Note that running actual DKG is ALWAYS recommended over a trusted dealer.
+package dealer
+
+import (
+	"crypto/rand"
+
+	"github.com/pkg/errors"
+
+	"github.com/sonr-io/sonr/crypto/core/curves"
+	"github.com/sonr-io/sonr/crypto/ot/base/simplest"
+	"github.com/sonr-io/sonr/crypto/ot/extension/kos"
+	"github.com/sonr-io/sonr/crypto/tecdsa/dklsv1/dkg"
+)
+
+// GenerateAndDeal produces private key material for alice and bob which they can later use in signing.
+// Running actual DKG is ALWAYS recommended over using this function, as this function breaks the security guarantees of DKG.
+// only use this function if you have a very good reason to.
+func GenerateAndDeal(curve *curves.Curve) (*dkg.AliceOutput, *dkg.BobOutput, error) {
+	aliceSecretShare, bobSecretShare, publicKey := produceKeyShares(curve)
+	aliceOTOutput, bobOTOutput, err := produceOTResults(curve)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "couldn't produce OT results")
+	}
+	alice := &dkg.AliceOutput{
+		PublicKey:      publicKey,
+		SecretKeyShare: aliceSecretShare,
+		SeedOtResult:   aliceOTOutput,
+	}
+	bob := &dkg.BobOutput{
+		PublicKey:      publicKey,
+		SecretKeyShare: bobSecretShare,
+		SeedOtResult:   bobOTOutput,
+	}
+	return alice, bob, nil
+}
+
+func produceKeyShares(
+	curve *curves.Curve,
+) (aliceSecretShare curves.Scalar, bobSecretShare curves.Scalar, publicKey curves.Point) {
+	aliceSecretShare = curve.Scalar.Random(rand.Reader)
+	bobSecretShare = curve.Scalar.Random(rand.Reader)
+	publicKey = curve.ScalarBaseMult(aliceSecretShare.Mul(bobSecretShare))
+	return aliceSecretShare, bobSecretShare, publicKey
+}
+
+func produceOTResults(
+	curve *curves.Curve,
+) (*simplest.ReceiverOutput, *simplest.SenderOutput, error) {
+	oneTimePadEncryptionKeys := make([]simplest.OneTimePadEncryptionKeys, kos.Kappa)
+	oneTimePadDecryptionKey := make([]simplest.OneTimePadDecryptionKey, kos.Kappa)
+
+	// we'll need a receiver because in its constructor random bits will be selected.
+	receiver, err := simplest.NewReceiver(curve, kos.Kappa, [simplest.DigestSize]byte{})
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "couldn't initialize a receiver")
+	}
+	packedRandomChoiceBits, randomChoiceBits := receiver.Output.PackedRandomChoiceBits, receiver.Output.RandomChoiceBits
+
+	for i := 0; i < kos.Kappa; i++ {
+		if _, err := rand.Read(oneTimePadEncryptionKeys[i][0][:]); err != nil {
+			return nil, nil, errors.WithStack(err)
+		}
+		if _, err := rand.Read(oneTimePadEncryptionKeys[i][1][:]); err != nil {
+			return nil, nil, errors.WithStack(err)
+		}
+		oneTimePadDecryptionKey[i] = oneTimePadEncryptionKeys[i][randomChoiceBits[i]]
+	}
+
+	senderOutput := &simplest.SenderOutput{
+		OneTimePadEncryptionKeys: oneTimePadEncryptionKeys,
+	}
+	receiverOutput := &simplest.ReceiverOutput{
+		PackedRandomChoiceBits:  packedRandomChoiceBits,
+		RandomChoiceBits:        randomChoiceBits,
+		OneTimePadDecryptionKey: oneTimePadDecryptionKey,
+	}
+	return receiverOutput, senderOutput, nil
+}