Add missing file

Author: konradkonrad

rolling-shutter/medley/testkeygen/testgenerator.go

@@ -0,0 +1,96 @@
+package testkeygen
+
+import (
+	"crypto/rand"
+
+	"github.com/shutter-network/shutter/shlib/shcrypto"
+
+	"github.com/shutter-network/rolling-shutter/rolling-shutter/medley/epochid"
+)
+
+// KeyGenerator is a helper tool to generate secret and public eon and epoch keys and key
+// shares. It will generate a new eon key every eonInterval epochs.
+type KeyGenerator struct {
+	eonInterval uint64
+	eonKeyGen   map[uint64]*EonKeys
+	NumKeypers  uint64
+	Threshold   uint64
+}
+
+func NewKeyGenerator(numKeypers uint64, threshold uint64) *KeyGenerator {
+	return &KeyGenerator{
+		eonInterval: 100, // 0 stands for infinity
+		eonKeyGen:   make(map[uint64]*EonKeys),
+		NumKeypers:  numKeypers,
+		Threshold:   threshold,
+	}
+}
+
+// getEonIndex computes the index of the EON key to be used for the given epochID. We generate a new
+// eon key every eonInterval epochs.
+func (kg *KeyGenerator) getEonIndex(epochID epochid.EpochID) uint64 {
+	if kg.eonInterval == 0 {
+		return 0
+	}
+
+	return epochID.Big().Uint64() / kg.eonInterval
+}
+
+func (kg *KeyGenerator) EonKeysForEpoch(epochID epochid.EpochID) *EonKeys {
+	eonIndex := kg.getEonIndex(epochID)
+	res, ok := kg.eonKeyGen[eonIndex]
+	var err error
+	if !ok {
+		res, err = NewEonKeys(
+			rand.Reader,
+			kg.NumKeypers,
+			kg.Threshold,
+		)
+		if err != nil {
+			return nil
+		}
+		kg.eonKeyGen[eonIndex] = res
+	}
+	return res
+}
+
+func (kg *KeyGenerator) EonPublicKeyShare(epochID epochid.EpochID, keyperIndex uint64) *shcrypto.EonPublicKeyShare {
+	return kg.EonKeysForEpoch(epochID).keyperShares[keyperIndex].eonPublicKeyShare
+}
+
+func (kg *KeyGenerator) EonPublicKey(epochID epochid.EpochID) *shcrypto.EonPublicKey {
+	return kg.EonKeysForEpoch(epochID).publicKey
+}
+
+func (kg *KeyGenerator) EonSecretKeyShare(epochID epochid.EpochID, keyperIndex uint64) *shcrypto.EonSecretKeyShare {
+	return kg.EonKeysForEpoch(epochID).keyperShares[keyperIndex].eonSecretKeyShare
+}
+
+func (kg *KeyGenerator) EpochSecretKeyShare(epochID epochid.EpochID, keyperIndex uint64) *shcrypto.EpochSecretKeyShare {
+	return kg.EonKeysForEpoch(epochID).keyperShares[keyperIndex].ComputeEpochSecretKeyShare(epochID)
+}
+
+func (kg *KeyGenerator) EpochSecretKey(epochID epochid.EpochID) *shcrypto.EpochSecretKey {
+	epochSecretKey, err := kg.EonKeysForEpoch(epochID).EpochSecretKey(epochID)
+	if err != nil {
+		panic(err)
+	}
+	return epochSecretKey
+}
+
+func (kg *KeyGenerator) RandomEpochID(epochbytes []byte) epochid.EpochID {
+	_, err := rand.Read(epochbytes)
+	if err != nil {
+		panic(err)
+	}
+
+	epochID, err := epochid.BytesToEpochID(epochbytes)
+	if err != nil {
+		panic(err)
+	}
+	return epochID
+}
+
+func (kg *KeyGenerator) RandomSigma() (shcrypto.Block, error) {
+	return shcrypto.RandomSigma(rand.Reader)
+}