use byte[] for signatures instead of strings

core/src/main/java/haveno/core/offer/OfferPayload.java

@@ -20,12 +20,15 @@ package haveno.core.offer;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonSerializationContext;
+import com.google.protobuf.ByteString;
+
 import haveno.common.crypto.Hash;
 import haveno.common.crypto.PubKeyRing;
 import haveno.common.proto.ProtoUtil;
 import haveno.common.util.CollectionUtils;
 import haveno.common.util.Hex;
 import haveno.common.util.JsonExclude;
+import haveno.common.util.Utilities;
 import haveno.network.p2p.NodeAddress;
 import haveno.network.p2p.storage.payload.ExpirablePayload;
 import haveno.network.p2p.storage.payload.ProtectedStoragePayload;
@@ -81,7 +84,7 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
     protected NodeAddress arbitratorSigner;
     @Setter
     @Nullable
-    protected String arbitratorSignature;
+    protected byte[] arbitratorSignature;
     @Setter
     @Nullable
     protected List<String> reserveTxKeyImages;
@@ -191,7 +194,7 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
                         @Nullable Map<String, String> extraDataMap,
                         int protocolVersion,
                         @Nullable NodeAddress arbitratorSigner,
-                        @Nullable String arbitratorSignature,
+                        @Nullable byte[] arbitratorSignature,
                         @Nullable List<String> reserveTxKeyImages) {
         this.id = id;
         this.date = date;
@@ -302,7 +305,7 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
         Optional.ofNullable(acceptedCountryCodes).ifPresent(builder::addAllAcceptedCountryCodes);
         Optional.ofNullable(hashOfChallenge).ifPresent(builder::setHashOfChallenge);
         Optional.ofNullable(extraDataMap).ifPresent(builder::putAllExtraData);
-        Optional.ofNullable(arbitratorSignature).ifPresent(builder::setArbitratorSignature);
+        Optional.ofNullable(arbitratorSignature).ifPresent(e -> builder.setArbitratorSignature(ByteString.copyFrom(e)));
         Optional.ofNullable(reserveTxKeyImages).ifPresent(builder::addAllReserveTxKeyImages);
 
         return protobuf.StoragePayload.newBuilder().setOfferPayload(builder).build();
@@ -352,7 +355,7 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
                 extraDataMapMap,
                 proto.getProtocolVersion(),
                 proto.hasArbitratorSigner() ? NodeAddress.fromProto(proto.getArbitratorSigner()) : null,
-                ProtoUtil.stringOrNullFromProto(proto.getArbitratorSignature()),
+                ProtoUtil.byteArrayOrNullFromProto(proto.getArbitratorSignature()),
                 proto.getReserveTxKeyImagesList() == null ? null : new ArrayList<String>(proto.getReserveTxKeyImagesList()));
     }
 
@@ -375,8 +378,6 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
                 ",\r\n     pubKeyRing=" + pubKeyRing +
                 ",\r\n     hash=" + (hash != null ? Hex.encode(hash) : "null") +
                 ",\r\n     extraDataMap=" + extraDataMap +
-                ",\r\n     arbitratorSigner=" + arbitratorSigner +
-                ",\r\n     arbitratorSignature=" + arbitratorSignature +
                 ",\r\n     reserveTxKeyImages=" + reserveTxKeyImages +
                 ",\r\n     marketPriceMargin=" + marketPriceMarginPct +
                 ",\r\n     useMarketBasedPrice=" + useMarketBasedPrice +
@@ -398,7 +399,7 @@ public final class OfferPayload implements ProtectedStoragePayload, ExpirablePay
                 ",\r\n     isPrivateOffer=" + isPrivateOffer +
                 ",\r\n     hashOfChallenge='" + hashOfChallenge + '\'' +
                 ",\n     arbitratorSigner=" + arbitratorSigner +
-                ",\n     arbitratorSignature=" + arbitratorSignature +
+                ",\n     arbitratorSignature=" + Utilities.bytesAsHexString(arbitratorSignature) +
                 "\r\n} ";
     }
 

core/src/main/java/haveno/core/offer/OpenOfferManager.java

@@ -25,7 +25,6 @@ import haveno.common.app.Capability;
 import haveno.common.app.Version;
 import haveno.common.crypto.KeyRing;
 import haveno.common.crypto.PubKeyRing;
-import haveno.common.crypto.Sig;
 import haveno.common.handlers.ErrorMessageHandler;
 import haveno.common.handlers.ResultHandler;
 import haveno.common.persistence.PersistenceManager;
@@ -1000,7 +999,7 @@ public class OpenOfferManager implements PeerManager.Listener, DecryptedDirectMe
 
             // arbitrator signs offer to certify they have valid reserve tx
             String offerPayloadAsJson = JsonUtil.objectToJson(request.getOfferPayload());
-            String signature = Sig.sign(keyRing.getSignatureKeyPair().getPrivate(), offerPayloadAsJson);
+            byte[] signature = HavenoUtils.sign(keyRing, offerPayloadAsJson);
             OfferPayload signedOfferPayload = request.getOfferPayload();
             signedOfferPayload.setArbitratorSignature(signature);
 
@@ -1119,7 +1118,7 @@ public class OpenOfferManager implements PeerManager.Listener, DecryptedDirectMe
         try {
             Optional<OpenOffer> openOfferOptional = getOpenOfferById(request.offerId);
             AvailabilityResult availabilityResult;
-            String makerSignature = null;
+            byte[] makerSignature = null;
             if (openOfferOptional.isPresent()) {
                 OpenOffer openOffer = openOfferOptional.get();
                 if (!apiUserDeniedByOffer(request)) {
@@ -1130,7 +1129,7 @@ public class OpenOfferManager implements PeerManager.Listener, DecryptedDirectMe
 
                                 // maker signs taker's request
                                 String tradeRequestAsJson = JsonUtil.objectToJson(request.getTradeRequest());
-                                makerSignature = Sig.sign(keyRing.getSignatureKeyPair().getPrivate(), tradeRequestAsJson);
+                                makerSignature = HavenoUtils.sign(keyRing, tradeRequestAsJson);
 
                                 try {
                                     // Check also tradePrice to avoid failures after taker fee is paid caused by a too big difference

core/src/main/java/haveno/core/offer/SignedOffer.java

@@ -17,10 +17,14 @@
 
 package haveno.core.offer;
 
+import haveno.common.proto.ProtoUtil;
 import haveno.common.proto.persistable.PersistablePayload;
 import haveno.core.util.JsonUtil;
 
 import java.util.List;
+
+import com.google.protobuf.ByteString;
+
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.extern.slf4j.Slf4j;
@@ -48,7 +52,7 @@ public final class SignedOffer implements PersistablePayload {
     @Getter
     private final long reserveTxMinerFee;
     @Getter
-    private final String arbitratorSignature;
+    private final byte[] arbitratorSignature;
     
     public SignedOffer(long timeStamp,
                        int traderId,
@@ -59,7 +63,7 @@ public final class SignedOffer implements PersistablePayload {
                        String reserveTxHex,
                        List<String> reserveTxKeyImages,
                        long reserveTxMinerFee,
-                       String arbitratorSignature) {
+                       byte[] arbitratorSignature) {
         this.timeStamp = timeStamp;
         this.traderId = traderId;
         this.offerId = offerId;
@@ -88,7 +92,7 @@ public final class SignedOffer implements PersistablePayload {
                 .setReserveTxHex(reserveTxHex)
                 .addAllReserveTxKeyImages(reserveTxKeyImages)
                 .setReserveTxMinerFee(reserveTxMinerFee)
-                .setArbitratorSignature(arbitratorSignature);
+                .setArbitratorSignature(ByteString.copyFrom(arbitratorSignature));
         return builder.build();
     }
 
@@ -102,7 +106,7 @@ public final class SignedOffer implements PersistablePayload {
                                proto.getReserveTxHex(),
                                proto.getReserveTxKeyImagesList(),
                                proto.getReserveTxMinerFee(),
-                               proto.getArbitratorSignature());
+                               ProtoUtil.byteArrayOrNullFromProto(proto.getArbitratorSignature()));
     }
 
 

core/src/main/java/haveno/core/offer/availability/OfferAvailabilityModel.java

@@ -61,7 +61,7 @@ public class OfferAvailabilityModel implements Model {
     @Nullable
     @Setter
     @Getter
-    private String makerSignature;
+    private byte[] makerSignature;
 
     // Added in v1.5.5
     @Getter

core/src/main/java/haveno/core/offer/availability/tasks/SendOfferAvailabilityRequest.java

@@ -17,9 +17,7 @@
 
 package haveno.core.offer.availability.tasks;
 
-import com.google.common.base.Charsets;
 import haveno.common.app.Version;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.Task;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.monetary.Price;
@@ -59,7 +57,7 @@ public class SendOfferAvailabilityRequest extends Task<OfferAvailabilityModel> {
             String payoutAddress = walletService.getOrCreateAddressEntry(offer.getId(), XmrAddressEntry.Context.TRADE_PAYOUT).getAddressString(); // reserve new payout address
 
             // taker signs offer using offer id as nonce to avoid challenge protocol
-            byte[] sig = Sig.sign(model.getP2PService().getKeyRing().getSignatureKeyPair().getPrivate(), offer.getId().getBytes(Charsets.UTF_8));
+            byte[] sig = HavenoUtils.sign(model.getP2PService().getKeyRing(), offer.getId());
 
             // get price
             Price price = offer.getPrice();

core/src/main/java/haveno/core/offer/messages/OfferAvailabilityResponse.java

@@ -31,6 +31,8 @@ import lombok.Value;
 
 import javax.annotation.Nullable;
 
+import com.google.protobuf.ByteString;
+
 // We add here the SupportedCapabilitiesMessage interface as that message always predates a direct connection
 // to the trading peer
 @EqualsAndHashCode(callSuper = true)
@@ -41,11 +43,11 @@ public final class OfferAvailabilityResponse extends OfferMessage implements Sup
     private final Capabilities supportedCapabilities;
 
     @Nullable
-    private final String makerSignature;
+    private byte[] makerSignature;
 
     public OfferAvailabilityResponse(String offerId,
                                      AvailabilityResult availabilityResult,
-                                     String makerSignature) {
+                                     @Nullable byte[] makerSignature) {
         this(offerId,
                 availabilityResult,
                 Capabilities.app,
@@ -64,7 +66,7 @@ public final class OfferAvailabilityResponse extends OfferMessage implements Sup
                                       @Nullable Capabilities supportedCapabilities,
                                       String messageVersion,
                                       @Nullable String uid,
-                                      String makerSignature) {
+                                      byte[] makerSignature) {
         super(messageVersion, offerId, uid);
         this.availabilityResult = availabilityResult;
         this.supportedCapabilities = supportedCapabilities;
@@ -79,7 +81,7 @@ public final class OfferAvailabilityResponse extends OfferMessage implements Sup
 
         Optional.ofNullable(supportedCapabilities).ifPresent(e -> builder.addAllSupportedCapabilities(Capabilities.toIntList(supportedCapabilities)));
         Optional.ofNullable(uid).ifPresent(e -> builder.setUid(uid));
-        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(makerSignature));
+        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(ByteString.copyFrom(e)));
 
         return getNetworkEnvelopeBuilder()
                 .setOfferAvailabilityResponse(builder)
@@ -92,6 +94,6 @@ public final class OfferAvailabilityResponse extends OfferMessage implements Sup
                 Capabilities.fromIntList(proto.getSupportedCapabilitiesList()),
                 messageVersion,
                 proto.getUid().isEmpty() ? null : proto.getUid(),
-                proto.getMakerSignature().isEmpty() ? null : proto.getMakerSignature());
+                ProtoUtil.byteArrayOrNullFromProto(proto.getMakerSignature()));
     }
 }

core/src/main/java/haveno/core/support/dispute/Dispute.java

@@ -104,9 +104,9 @@ public final class Dispute implements NetworkPayload, PersistablePayload {
     private final String payoutTxId;
     private String contractAsJson;
     @Nullable
-    private final String makerContractSignature;
+    private final byte[] makerContractSignature;
     @Nullable
-    private final String takerContractSignature;
+    private final byte[] takerContractSignature;
     private final PubKeyRing agentPubKeyRing; // dispute agent
     private final boolean isSupportTicket;
     private final ObservableList<ChatMessage> chatMessages = FXCollections.observableArrayList();
@@ -179,8 +179,8 @@ public final class Dispute implements NetworkPayload, PersistablePayload {
                    @Nullable String depositTxId,
                    @Nullable String payoutTxId,
                    String contractAsJson,
-                   @Nullable String makerContractSignature,
+                   @Nullable byte[] makerContractSignature,
-                   @Nullable String takerContractSignature,
+                   @Nullable byte[] takerContractSignature,
                    @Nullable PaymentAccountPayload makerPaymentAccountPayload,
                    @Nullable PaymentAccountPayload takerPaymentAccountPayload,
                    PubKeyRing agentPubKeyRing,
@@ -251,8 +251,8 @@ public final class Dispute implements NetworkPayload, PersistablePayload {
         Optional.ofNullable(depositTxId).ifPresent(builder::setDepositTxId);
         Optional.ofNullable(payoutTxId).ifPresent(builder::setPayoutTxId);
         Optional.ofNullable(disputePayoutTxId).ifPresent(builder::setDisputePayoutTxId);
-        Optional.ofNullable(makerContractSignature).ifPresent(builder::setMakerContractSignature);
+        Optional.ofNullable(makerContractSignature).ifPresent(e -> builder.setMakerContractSignature(ByteString.copyFrom(e)));
-        Optional.ofNullable(takerContractSignature).ifPresent(builder::setTakerContractSignature);
+        Optional.ofNullable(takerContractSignature).ifPresent(e -> builder.setTakerContractSignature(ByteString.copyFrom(e)));
         Optional.ofNullable(makerPaymentAccountPayload).ifPresent(e -> builder.setMakerPaymentAccountPayload((protobuf.PaymentAccountPayload) makerPaymentAccountPayload.toProtoMessage()));
         Optional.ofNullable(takerPaymentAccountPayload).ifPresent(e -> builder.setTakerPaymentAccountPayload((protobuf.PaymentAccountPayload) takerPaymentAccountPayload.toProtoMessage()));
         Optional.ofNullable(disputeResultProperty.get()).ifPresent(result -> builder.setDisputeResult(disputeResultProperty.get().toProtoMessage()));
@@ -281,8 +281,8 @@ public final class Dispute implements NetworkPayload, PersistablePayload {
                 ProtoUtil.stringOrNullFromProto(proto.getDepositTxId()),
                 ProtoUtil.stringOrNullFromProto(proto.getPayoutTxId()),
                 proto.getContractAsJson(),
-                ProtoUtil.stringOrNullFromProto(proto.getMakerContractSignature()),
+                ProtoUtil.byteArrayOrNullFromProto(proto.getMakerContractSignature()),
-                ProtoUtil.stringOrNullFromProto(proto.getTakerContractSignature()),
+                ProtoUtil.byteArrayOrNullFromProto(proto.getTakerContractSignature()),
                 proto.hasMakerPaymentAccountPayload() ? coreProtoResolver.fromProto(proto.getMakerPaymentAccountPayload()) : null,
                 proto.hasTakerPaymentAccountPayload() ? coreProtoResolver.fromProto(proto.getTakerPaymentAccountPayload()) : null,
                 PubKeyRing.fromProto(proto.getAgentPubKeyRing()),
@@ -524,8 +524,8 @@ public final class Dispute implements NetworkPayload, PersistablePayload {
                 ",\n     depositTxId='" + depositTxId + '\'' +
                 ",\n     payoutTxId='" + payoutTxId + '\'' +
                 ",\n     contractAsJson='" + contractAsJson + '\'' +
-                ",\n     makerContractSignature='" + makerContractSignature + '\'' +
+                ",\n     makerContractSignature='" + Utilities.bytesAsHexString(makerContractSignature) + '\'' +
-                ",\n     takerContractSignature='" + takerContractSignature + '\'' +
+                ",\n     takerContractSignature='" + Utilities.bytesAsHexString(takerContractSignature) + '\'' +
                 ",\n     agentPubKeyRing=" + agentPubKeyRing +
                 ",\n     isSupportTicket=" + isSupportTicket +
                 ",\n     chatMessages=" + chatMessages +

core/src/main/java/haveno/core/support/dispute/DisputeSummaryVerification.java

@@ -17,16 +17,14 @@
 
 package haveno.core.support.dispute;
 
-import haveno.common.crypto.CryptoException;
 import haveno.common.crypto.Hash;
-import haveno.common.crypto.Sig;
 import haveno.common.util.Utilities;
 import haveno.core.locale.Res;
 import haveno.core.support.dispute.agent.DisputeAgent;
 import haveno.core.support.dispute.arbitration.arbitrator.ArbitratorManager;
+import haveno.core.trade.HavenoUtils;
 import haveno.network.p2p.NodeAddress;
 import java.security.KeyPair;
-import java.security.PublicKey;
 
 import lombok.extern.slf4j.Slf4j;
 
@@ -46,10 +44,10 @@ public class DisputeSummaryVerification {
         KeyPair signatureKeyPair = disputeManager.getSignatureKeyPair();
         String sigAsHex;
         try {
-            byte[] signature = Sig.sign(signatureKeyPair.getPrivate(), hash);
+            byte[] signature = HavenoUtils.sign(signatureKeyPair.getPrivate(), hash);
             sigAsHex = Utilities.encodeToHex(signature);
             disputeResult.setArbitratorSignature(signature);
-        } catch (CryptoException e) {
+        } catch (Exception e) {
             sigAsHex = "Signing failed";
         }
 
@@ -69,19 +67,13 @@ public class DisputeSummaryVerification {
             NodeAddress nodeAddress = new NodeAddress(fullAddress);
             DisputeAgent disputeAgent = arbitratorMediator.getDisputeAgentByNodeAddress(nodeAddress).orElse(null);
             checkNotNull(disputeAgent, "Dispute agent is null");
-            PublicKey pubKey = disputeAgent.getPubKeyRing().getSignaturePubKey();
 
             String sigString = parts[1].split(SEPARATOR2)[0];
             byte[] sig = Utilities.decodeFromHex(sigString);
             byte[] hash = Hash.getSha256Hash(textToSign);
             try {
-                boolean result = Sig.verify(pubKey, hash, sig);
+                HavenoUtils.verifySignature(disputeAgent.getPubKeyRing(), hash, sig);
-                if (result) {
+            } catch (Exception e) {
-                    return;
-                } else {
-                    throw new IllegalArgumentException(Res.get("support.sigCheck.popup.failed"));
-                }
-            } catch (CryptoException e) {
                 throw new IllegalArgumentException(Res.get("support.sigCheck.popup.failed"));
             }
         } catch (Throwable e) {

core/src/main/java/haveno/core/support/dispute/DisputeValidation.java

@@ -18,12 +18,11 @@
 package haveno.core.support.dispute;
 
 import haveno.common.config.Config;
-import haveno.common.crypto.CryptoException;
 import haveno.common.crypto.Hash;
-import haveno.common.crypto.Sig;
 import haveno.common.util.Tuple3;
 import haveno.core.support.SupportType;
 import haveno.core.trade.Contract;
+import haveno.core.trade.HavenoUtils;
 import haveno.core.trade.Trade;
 import haveno.core.util.JsonUtil;
 import haveno.core.util.validation.RegexValidatorFactory;
@@ -64,23 +63,11 @@ public class DisputeValidation {
             checkArgument(Arrays.equals(Objects.requireNonNull(dispute.getContractHash()), Hash.getSha256Hash(checkNotNull(dispute.getContractAsJson()))),
                     "Invalid contractHash");
  
-            try {
             // Only the dispute opener has set the signature
-                String makerContractSignature = dispute.getMakerContractSignature();
+            byte[] makerContractSignature = dispute.getMakerContractSignature();
-                if (makerContractSignature != null) {
+            if (makerContractSignature != null) HavenoUtils.verifySignature(contract.getMakerPubKeyRing(),  dispute.getContractAsJson(), makerContractSignature);
-                    Sig.verify(contract.getMakerPubKeyRing().getSignaturePubKey(),
+            byte[] takerContractSignature = dispute.getTakerContractSignature();
-                            dispute.getContractAsJson(),
+            if (takerContractSignature != null) HavenoUtils.verifySignature(contract.getTakerPubKeyRing(),  dispute.getContractAsJson(), takerContractSignature);
-                            makerContractSignature);
-                }
-                String takerContractSignature = dispute.getTakerContractSignature();
-                if (takerContractSignature != null) {
-                    Sig.verify(contract.getTakerPubKeyRing().getSignaturePubKey(),
-                            dispute.getContractAsJson(),
-                            takerContractSignature);
-                }
-            } catch (CryptoException e) {
-                throw new ValidationException(dispute, e.getMessage());
-            }
         } catch (Throwable t) {
             throw new ValidationException(dispute, t.getMessage());
         }

core/src/main/java/haveno/core/trade/HavenoUtils.java

@@ -23,6 +23,7 @@ import com.google.common.base.CaseFormat;
 import com.google.common.base.Charsets;
 import haveno.common.config.Config;
 import haveno.common.crypto.Hash;
+import haveno.common.crypto.KeyRing;
 import haveno.common.crypto.PubKeyRing;
 import haveno.common.crypto.Sig;
 import haveno.common.util.Utilities;
@@ -39,7 +40,7 @@ import java.text.DecimalFormat;
 import java.text.SimpleDateFormat;
 
 import java.net.URI;
-
+import java.security.PrivateKey;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
@@ -236,6 +237,170 @@ public class HavenoUtils {
         return feePerXmrAsDecimal.multiply(amountMultiplier).toBigInteger();
     }
 
+    // ------------------------ SIGNING AND VERIFYING -------------------------
+
+    public static byte[] sign(KeyRing keyRing, String message) {
+        return sign(keyRing.getSignatureKeyPair().getPrivate(), message);
+    }
+
+    public static byte[] sign(PrivateKey privateKey, String message) {
+        return sign(privateKey, message.getBytes(Charsets.UTF_8));
+    }
+
+    public static byte[] sign(PrivateKey privateKey, byte[] bytes) {
+        try {
+            return Sig.sign(privateKey, bytes);
+        } catch (Exception e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+    public static void verifySignature(PubKeyRing pubKeyRing, String message, byte[] signature) {
+        verifySignature(pubKeyRing, message.getBytes(Charsets.UTF_8), signature);
+    }
+
+    public static void verifySignature(PubKeyRing pubKeyRing, byte[] bytes, byte[] signature) {
+        try {
+            Sig.verify(pubKeyRing.getSignaturePubKey(), bytes, signature);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static boolean isSignatureValid(PubKeyRing pubKeyRing, String message, byte[] signature) {
+        return isSignatureValid(pubKeyRing, message.getBytes(Charsets.UTF_8), signature);
+    }
+
+    public static boolean isSignatureValid(PubKeyRing pubKeyRing, byte[] bytes, byte[] signature) {
+        try {
+            verifySignature(pubKeyRing, bytes, signature);
+            return true;
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    /**
+     * Check if the arbitrator signature is valid for an offer.
+     *
+     * @param offer is a signed offer with payload
+     * @param arbitrator is the original signing arbitrator
+     * @return true if the arbitrator's signature is valid for the offer
+     */
+    public static boolean isArbitratorSignatureValid(Offer offer, Arbitrator arbitrator) {
+
+        // copy offer payload
+        OfferPayload offerPayloadCopy = OfferPayload.fromProto(offer.toProtoMessage().getOfferPayload());
+
+        // remove arbitrator signature from signed payload
+        byte[] signature = offerPayloadCopy.getArbitratorSignature();
+        offerPayloadCopy.setArbitratorSignature(null);
+
+        // get unsigned offer payload as json string
+        String unsignedOfferAsJson = JsonUtil.objectToJson(offerPayloadCopy);
+
+        // verify signature
+        return isSignatureValid(arbitrator.getPubKeyRing(), unsignedOfferAsJson, signature);
+    }
+
+    /**
+     * Check if the maker signature for a trade request is valid.
+     *
+     * @param request is the trade request to check
+     * @return true if the maker's signature is valid for the trade request
+     */
+    public static boolean isMakerSignatureValid(InitTradeRequest request, byte[] signature, PubKeyRing makerPubKeyRing) {
+
+        // re-create trade request with signed fields
+        InitTradeRequest signedRequest = new InitTradeRequest(
+                request.getTradeId(),
+                request.getSenderNodeAddress(),
+                request.getPubKeyRing(),
+                request.getTradeAmount(),
+                request.getTradePrice(),
+                request.getTradeFee(),
+                request.getAccountId(),
+                request.getPaymentAccountId(),
+                request.getPaymentMethodId(),
+                request.getUid(),
+                request.getMessageVersion(),
+                request.getAccountAgeWitnessSignatureOfOfferId(),
+                request.getCurrentDate(),
+                request.getMakerNodeAddress(),
+                request.getTakerNodeAddress(),
+                null,
+                null,
+                null,
+                null,
+                request.getPayoutAddress(),
+                null
+                );
+
+        // get trade request as string
+        String tradeRequestAsJson = JsonUtil.objectToJson(signedRequest);
+
+        // verify maker signature
+        return isSignatureValid(makerPubKeyRing, tradeRequestAsJson, signature);
+    }
+
+    /**
+     * Verify the buyer signature for a PaymentSentMessage.
+     *
+     * @param trade - the trade to verify
+     * @param message - signed payment sent message to verify
+     * @return true if the buyer's signature is valid for the message
+     */
+    public static void verifyPaymentSentMessage(Trade trade, PaymentSentMessage message) {
+
+        // remove signature from message
+        byte[] signature = message.getBuyerSignature();
+        message.setBuyerSignature(null);
+
+        // get unsigned message as json string
+        String unsignedMessageAsJson = JsonUtil.objectToJson(message);
+
+        // replace signature
+        message.setBuyerSignature(signature);
+
+        // verify signature
+        if (!isSignatureValid(trade.getBuyer().getPubKeyRing(), unsignedMessageAsJson, signature)) {
+            throw new IllegalArgumentException("The buyer signature is invalid for the " + message.getClass().getSimpleName() + " for " + trade.getClass().getSimpleName() + " " + trade.getId());
+        }
+
+        // verify trade id
+        if (!trade.getId().equals(message.getTradeId())) throw new IllegalArgumentException("The " + message.getClass().getSimpleName() + " has the wrong trade id, expected " + trade.getId() + " but was " + message.getTradeId());
+    }
+
+    /**
+     * Verify the seller signature for a PaymentReceivedMessage.
+     *
+     * @param trade - the trade to verify
+     * @param message - signed payment received message to verify
+     * @return true if the seller's signature is valid for the message
+     */
+    public static void verifyPaymentReceivedMessage(Trade trade, PaymentReceivedMessage message) {
+
+        // remove signature from message
+        byte[] signature = message.getSellerSignature();
+        message.setSellerSignature(null);
+
+        // get unsigned message as json string
+        String unsignedMessageAsJson = JsonUtil.objectToJson(message);
+
+        // replace signature
+        message.setSellerSignature(signature);
+
+        // verify signature
+        if (!isSignatureValid(trade.getSeller().getPubKeyRing(), unsignedMessageAsJson, signature)) {
+            throw new IllegalArgumentException("The seller signature is invalid for the " + message.getClass().getSimpleName() + " for " + trade.getClass().getSimpleName() + " " + trade.getId());
+        }
+
+        // verify trade id
+        if (!trade.getId().equals(message.getTradeId())) throw new IllegalArgumentException("The " + message.getClass().getSimpleName() + " has the wrong trade id, expected " + trade.getId() + " but was " + message.getTradeId());
+
+        // verify buyer signature of payment sent message
+        verifyPaymentSentMessage(trade, message.getPaymentSentMessage());
+    }
 
     // ----------------------------- OTHER UTILS ------------------------------
 
@@ -282,144 +447,6 @@ public class HavenoUtils {
         return Utilities.bytesAsHexString(Hash.getSha256Ripemd160hash(uniqueId.getBytes(Charsets.UTF_8)));
     }
 
-    /**
-     * Check if the arbitrator signature is valid for an offer.
-     *
-     * @param offer is a signed offer with payload
-     * @param arbitrator is the original signing arbitrator
-     * @return true if the arbitrator's signature is valid for the offer
-     */
-    public static boolean isArbitratorSignatureValid(Offer offer, Arbitrator arbitrator) {
-
-        // copy offer payload
-        OfferPayload offerPayloadCopy = OfferPayload.fromProto(offer.toProtoMessage().getOfferPayload());
-
-        // remove arbitrator signature from signed payload
-        String signature = offerPayloadCopy.getArbitratorSignature();
-        offerPayloadCopy.setArbitratorSignature(null);
-
-        // get unsigned offer payload as json string
-        String unsignedOfferAsJson = JsonUtil.objectToJson(offerPayloadCopy);
-
-        // verify arbitrator signature
-        try {
-            return Sig.verify(arbitrator.getPubKeyRing().getSignaturePubKey(), unsignedOfferAsJson, signature);
-        } catch (Exception e) {
-            return false;
-        }
-    }
-
-    /**
-     * Check if the maker signature for a trade request is valid.
-     *
-     * @param request is the trade request to check
-     * @return true if the maker's signature is valid for the trade request
-     */
-    public static boolean isMakerSignatureValid(InitTradeRequest request, String signature, PubKeyRing makerPubKeyRing) {
-
-        // re-create trade request with signed fields
-        InitTradeRequest signedRequest = new InitTradeRequest(
-                request.getTradeId(),
-                request.getSenderNodeAddress(),
-                request.getPubKeyRing(),
-                request.getTradeAmount(),
-                request.getTradePrice(),
-                request.getTradeFee(),
-                request.getAccountId(),
-                request.getPaymentAccountId(),
-                request.getPaymentMethodId(),
-                request.getUid(),
-                request.getMessageVersion(),
-                request.getAccountAgeWitnessSignatureOfOfferId(),
-                request.getCurrentDate(),
-                request.getMakerNodeAddress(),
-                request.getTakerNodeAddress(),
-                null,
-                null,
-                null,
-                null,
-                request.getPayoutAddress(),
-                null
-                );
-
-        // get trade request as string
-        String tradeRequestAsJson = JsonUtil.objectToJson(signedRequest);
-
-        // verify maker signature
-        try {
-            return Sig.verify(makerPubKeyRing.getSignaturePubKey(),
-                    tradeRequestAsJson,
-                    signature);
-        } catch (Exception e) {
-            return false;
-        }
-    }
-
-    /**
-     * Verify the buyer signature for a PaymentSentMessage.
-     *
-     * @param trade - the trade to verify
-     * @param message - signed payment sent message to verify
-     * @return true if the buyer's signature is valid for the message
-     */
-    public static void verifyPaymentSentMessage(Trade trade, PaymentSentMessage message) {
-
-        // remove signature from message
-        byte[] signature = message.getBuyerSignature();
-        message.setBuyerSignature(null);
-
-        // get unsigned message as json string
-        String unsignedMessageAsJson = JsonUtil.objectToJson(message);
-
-        // replace signature
-        message.setBuyerSignature(signature);
-
-        // verify signature
-        String errMessage = "The buyer signature is invalid for the " + message.getClass().getSimpleName() + " for " + trade.getClass().getSimpleName() + " " + trade.getId();
-        try {
-            if (!Sig.verify(trade.getBuyer().getPubKeyRing().getSignaturePubKey(), unsignedMessageAsJson.getBytes(Charsets.UTF_8), signature)) throw new IllegalArgumentException(errMessage);
-        } catch (Exception e) {
-            throw new IllegalArgumentException(errMessage);
-        }
-
-        // verify trade id
-        if (!trade.getId().equals(message.getTradeId())) throw new IllegalArgumentException("The " + message.getClass().getSimpleName() + " has the wrong trade id, expected " + trade.getId() + " but was " + message.getTradeId());
-    }
-
-    /**
-     * Verify the seller signature for a PaymentReceivedMessage.
-     *
-     * @param trade - the trade to verify
-     * @param message - signed payment received message to verify
-     * @return true if the seller's signature is valid for the message
-     */
-    public static void verifyPaymentReceivedMessage(Trade trade, PaymentReceivedMessage message) {
-
-        // remove signature from message
-        byte[] signature = message.getSellerSignature();
-        message.setSellerSignature(null);
-
-        // get unsigned message as json string
-        String unsignedMessageAsJson = JsonUtil.objectToJson(message);
-
-        // replace signature
-        message.setSellerSignature(signature);
-
-        // verify signature
-        String errMessage = "The seller signature is invalid for the " + message.getClass().getSimpleName() + " for " + trade.getClass().getSimpleName() + " " + trade.getId();
-        try {
-            if (!Sig.verify(trade.getSeller().getPubKeyRing().getSignaturePubKey(), unsignedMessageAsJson.getBytes(Charsets.UTF_8), signature)) throw new IllegalArgumentException(errMessage);
-        } catch (Exception e) {
-            throw new IllegalArgumentException(errMessage);
-        }
-
-        // verify trade id
-        if (!trade.getId().equals(message.getTradeId())) throw new IllegalArgumentException("The " + message.getClass().getSimpleName() + " has the wrong trade id, expected " + trade.getId() + " but was " + message.getTradeId());
-
-        // verify buyer signature of payment sent message
-        verifyPaymentSentMessage(trade, message.getPaymentSentMessage());
-    }
-
     public static void awaitLatch(CountDownLatch latch) {
         try {
             latch.await();

core/src/main/java/haveno/core/trade/messages/DepositRequest.java

@@ -19,6 +19,7 @@ package haveno.core.trade.messages;
 
 import com.google.protobuf.ByteString;
 import haveno.common.proto.ProtoUtil;
+import haveno.common.util.Utilities;
 import haveno.core.proto.CoreProtoResolver;
 import haveno.network.p2p.DirectMessage;
 import java.util.Optional;
@@ -30,7 +31,7 @@ import lombok.Value;
 @Value
 public final class DepositRequest extends TradeMessage implements DirectMessage {
     private final long currentDate;
-    private final String contractSignature;
+    private final byte[] contractSignature;
     private final String depositTxHex;
     private final String depositTxKey;
     @Nullable
@@ -40,7 +41,7 @@ public final class DepositRequest extends TradeMessage implements DirectMessage
                                      String uid,
                                      String messageVersion,
                                      long currentDate,
-                                     String contractSignature,
+                                     byte[] contractSignature,
                                      String depositTxHex,
                                      String depositTxKey,
                                      @Nullable byte[] paymentAccountKey) {
@@ -62,11 +63,11 @@ public final class DepositRequest extends TradeMessage implements DirectMessage
         protobuf.DepositRequest.Builder builder = protobuf.DepositRequest.newBuilder()
                 .setTradeId(tradeId)
                 .setUid(uid)
-                .setContractSignature(contractSignature)
                 .setDepositTxHex(depositTxHex)
                 .setDepositTxKey(depositTxKey);
         builder.setCurrentDate(currentDate);
         Optional.ofNullable(paymentAccountKey).ifPresent(e -> builder.setPaymentAccountKey(ByteString.copyFrom(e)));
+        Optional.ofNullable(contractSignature).ifPresent(e -> builder.setContractSignature(ByteString.copyFrom(e)));
 
         return getNetworkEnvelopeBuilder().setDepositRequest(builder).build();
     }
@@ -78,7 +79,7 @@ public final class DepositRequest extends TradeMessage implements DirectMessage
                 proto.getUid(),
                 messageVersion,
                 proto.getCurrentDate(),
-                proto.getContractSignature(),
+                ProtoUtil.byteArrayOrNullFromProto(proto.getContractSignature()),
                 proto.getDepositTxHex(),
                 proto.getDepositTxKey(),
                 ProtoUtil.byteArrayOrNullFromProto(proto.getPaymentAccountKey()));
@@ -88,7 +89,7 @@ public final class DepositRequest extends TradeMessage implements DirectMessage
     public String toString() {
         return "DepositRequest {" +
                 ",\n     currentDate=" + currentDate +
-                ",\n     contractSignature=" + contractSignature +
+                ",\n     contractSignature=" + Utilities.bytesAsHexString(contractSignature) +
                 ",\n     depositTxHex='" + depositTxHex +
                 ",\n     depositTxKey='" + depositTxKey +
                 ",\n     paymentAccountKey='" + paymentAccountKey +

core/src/main/java/haveno/core/trade/messages/InitTradeRequest.java

@@ -62,7 +62,7 @@ public final class InitTradeRequest extends TradeMessage implements DirectMessag
     @Nullable
     private final String payoutAddress;
     @Nullable
-    private final String makerSignature;
+    private final byte[] makerSignature;
 
     public InitTradeRequest(String tradeId,
                                      NodeAddress senderNodeAddress,
@@ -84,7 +84,7 @@ public final class InitTradeRequest extends TradeMessage implements DirectMessag
                                      @Nullable String reserveTxHex,
                                      @Nullable String reserveTxKey,
                                      @Nullable String payoutAddress,
-                                     @Nullable String makerSignature) {
+                                     @Nullable byte[] makerSignature) {
         super(messageVersion, tradeId, uid);
         this.senderNodeAddress = senderNodeAddress;
         this.pubKeyRing = pubKeyRing;
@@ -133,7 +133,7 @@ public final class InitTradeRequest extends TradeMessage implements DirectMessag
         Optional.ofNullable(reserveTxKey).ifPresent(e -> builder.setReserveTxKey(reserveTxKey));
         Optional.ofNullable(payoutAddress).ifPresent(e -> builder.setPayoutAddress(payoutAddress));
         Optional.ofNullable(accountAgeWitnessSignatureOfOfferId).ifPresent(e -> builder.setAccountAgeWitnessSignatureOfOfferId(ByteString.copyFrom(e)));
-        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(makerSignature));
+        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(ByteString.copyFrom(e)));
         builder.setCurrentDate(currentDate);
 
         return getNetworkEnvelopeBuilder().setInitTradeRequest(builder).build();
@@ -162,7 +162,7 @@ public final class InitTradeRequest extends TradeMessage implements DirectMessag
                 ProtoUtil.stringOrNullFromProto(proto.getReserveTxHex()),
                 ProtoUtil.stringOrNullFromProto(proto.getReserveTxKey()),
                 ProtoUtil.stringOrNullFromProto(proto.getPayoutAddress()),
-                ProtoUtil.stringOrNullFromProto(proto.getMakerSignature()));
+                ProtoUtil.byteArrayOrNullFromProto(proto.getMakerSignature()));
     }
 
     @Override
@@ -183,7 +183,7 @@ public final class InitTradeRequest extends TradeMessage implements DirectMessag
                 ",\n     reserveTxHex=" + reserveTxHex +
                 ",\n     reserveTxKey=" + reserveTxKey +
                 ",\n     payoutAddress=" + payoutAddress +
-                ",\n     makerSignature=" + makerSignature +
+                ",\n     makerSignature=" + Utilities.byteArrayToInteger(makerSignature) +
                 "\n} " + super.toString();
     }
 }

core/src/main/java/haveno/core/trade/messages/SignContractResponse.java

@@ -18,11 +18,10 @@
 package haveno.core.trade.messages;
 
 import com.google.protobuf.ByteString;
-import haveno.common.crypto.PubKeyRing;
 import haveno.common.proto.ProtoUtil;
+import haveno.common.util.Utilities;
 import haveno.core.proto.CoreProtoResolver;
 import haveno.network.p2p.DirectMessage;
-import haveno.network.p2p.NodeAddress;
 import java.util.Optional;
 import javax.annotation.Nullable;
 import lombok.EqualsAndHashCode;
@@ -33,7 +32,7 @@ import lombok.Value;
 public final class SignContractResponse extends TradeMessage implements DirectMessage {
     private final long currentDate;
     private final String contractAsJson;
-    private final String contractSignature;
+    private final byte[] contractSignature;
     private final byte[] encryptedPaymentAccountPayload;
 
     public SignContractResponse(String tradeId,
@@ -41,7 +40,7 @@ public final class SignContractResponse extends TradeMessage implements DirectMe
                                      String messageVersion,
                                      long currentDate,
                                      String contractAsJson,
-                                     String contractSignature,
+                                     byte[] contractSignature,
                                      @Nullable byte[] encryptedPaymentAccountPayload) {
         super(messageVersion, tradeId, uid);
         this.currentDate = currentDate;
@@ -62,7 +61,7 @@ public final class SignContractResponse extends TradeMessage implements DirectMe
                 .setUid(uid);
 
         Optional.ofNullable(contractAsJson).ifPresent(e -> builder.setContractAsJson(contractAsJson));
-        Optional.ofNullable(contractSignature).ifPresent(e -> builder.setContractSignature(contractSignature));
+        Optional.ofNullable(contractSignature).ifPresent(e -> builder.setContractSignature(ByteString.copyFrom(e)));
         Optional.ofNullable(encryptedPaymentAccountPayload).ifPresent(e -> builder.setEncryptedPaymentAccountPayload(ByteString.copyFrom(e)));
 
         builder.setCurrentDate(currentDate);
@@ -78,7 +77,7 @@ public final class SignContractResponse extends TradeMessage implements DirectMe
                 messageVersion,
                 proto.getCurrentDate(),
                 ProtoUtil.stringOrNullFromProto(proto.getContractAsJson()),
-                ProtoUtil.stringOrNullFromProto(proto.getContractSignature()),
+                ProtoUtil.byteArrayOrNullFromProto(proto.getContractSignature()),
                 proto.getEncryptedPaymentAccountPayload().toByteArray());
     }
 
@@ -87,7 +86,7 @@ public final class SignContractResponse extends TradeMessage implements DirectMe
         return "SignContractResponse {" +
                 ",\n     currentDate=" + currentDate +
                 ",\n     contractAsJson='" + contractAsJson +
-                ",\n     contractSignature='" + contractSignature +
+                ",\n     contractSignature='" + Utilities.bytesAsHexString(contractSignature) +
                 "\n} " + super.toString();
     }
 }

core/src/main/java/haveno/core/trade/protocol/ProcessModel.java

@@ -137,7 +137,7 @@ public class ProcessModel implements Model, PersistablePayload {
     transient private TradeMessage tradeMessage;
     @Getter
     @Setter
-    private String makerSignature;
+    private byte[] makerSignature;
     @Nullable
     @Getter
     @Setter
@@ -220,7 +220,8 @@ public class ProcessModel implements Model, PersistablePayload {
         Optional.ofNullable(takeOfferFeeTxId).ifPresent(builder::setTakeOfferFeeTxId);
         Optional.ofNullable(payoutTxSignature).ifPresent(e -> builder.setPayoutTxSignature(ByteString.copyFrom(payoutTxSignature)));
         Optional.ofNullable(tempTradePeerNodeAddress).ifPresent(e -> builder.setTempTradePeerNodeAddress(tempTradePeerNodeAddress.toProtoMessage()));
-        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(makerSignature));
+        Optional.ofNullable(mediatedPayoutTxSignature).ifPresent(e -> builder.setMediatedPayoutTxSignature(ByteString.copyFrom(e)));
+        Optional.ofNullable(makerSignature).ifPresent(e -> builder.setMakerSignature(ByteString.copyFrom(e)));
         Optional.ofNullable(multisigAddress).ifPresent(e -> builder.setMultisigAddress(multisigAddress));
         Optional.ofNullable(paymentSentMessage).ifPresent(e -> builder.setPaymentSentMessage(paymentSentMessage.toProtoNetworkEnvelope().getPaymentSentMessage()));
         Optional.ofNullable(paymentReceivedMessage).ifPresent(e -> builder.setPaymentReceivedMessage(paymentReceivedMessage.toProtoNetworkEnvelope().getPaymentReceivedMessage()));
@@ -245,7 +246,7 @@ public class ProcessModel implements Model, PersistablePayload {
         processModel.setPayoutTxSignature(ProtoUtil.byteArrayOrNullFromProto(proto.getPayoutTxSignature()));
         processModel.setTempTradePeerNodeAddress(proto.hasTempTradePeerNodeAddress() ? NodeAddress.fromProto(proto.getTempTradePeerNodeAddress()) : null);
         processModel.setMediatedPayoutTxSignature(ProtoUtil.byteArrayOrNullFromProto(proto.getMediatedPayoutTxSignature()));
-        processModel.setMakerSignature(proto.getMakerSignature());
+        processModel.setMakerSignature(ProtoUtil.byteArrayOrNullFromProto(proto.getMakerSignature()));
         processModel.setMultisigAddress(ProtoUtil.stringOrNullFromProto(proto.getMultisigAddress()));
 
         String paymentSentMessageStateString = ProtoUtil.stringOrNullFromProto(proto.getPaymentSentMessageState());

core/src/main/java/haveno/core/trade/protocol/TradePeer.java

@@ -79,7 +79,7 @@ public final class TradePeer implements PersistablePayload {
     @Nullable
     private String contractAsJson;
     @Nullable
-    private String contractSignature;
+    private byte[] contractSignature;
 
     // added in v 0.6
     @Nullable
@@ -146,7 +146,7 @@ public final class TradePeer implements PersistablePayload {
         Optional.ofNullable(paymentAccountPayload).ifPresent(e -> builder.setPaymentAccountPayload((protobuf.PaymentAccountPayload) e.toProtoMessage()));
         Optional.ofNullable(payoutAddressString).ifPresent(builder::setPayoutAddressString);
         Optional.ofNullable(contractAsJson).ifPresent(builder::setContractAsJson);
-        Optional.ofNullable(contractSignature).ifPresent(builder::setContractSignature);
+        Optional.ofNullable(contractSignature).ifPresent(e -> builder.setContractSignature(ByteString.copyFrom(e)));
         Optional.ofNullable(pubKeyRing).ifPresent(e -> builder.setPubKeyRing(e.toProtoMessage()));
         Optional.ofNullable(accountAgeWitnessNonce).ifPresent(e -> builder.setAccountAgeWitnessNonce(ByteString.copyFrom(e)));
         Optional.ofNullable(accountAgeWitnessSignature).ifPresent(e -> builder.setAccountAgeWitnessSignature(ByteString.copyFrom(e)));
@@ -185,7 +185,7 @@ public final class TradePeer implements PersistablePayload {
             tradePeer.setPaymentAccountPayload(proto.hasPaymentAccountPayload() ? coreProtoResolver.fromProto(proto.getPaymentAccountPayload()) : null);
             tradePeer.setPayoutAddressString(ProtoUtil.stringOrNullFromProto(proto.getPayoutAddressString()));
             tradePeer.setContractAsJson(ProtoUtil.stringOrNullFromProto(proto.getContractAsJson()));
-            tradePeer.setContractSignature(ProtoUtil.stringOrNullFromProto(proto.getContractSignature()));
+            tradePeer.setContractSignature(ProtoUtil.byteArrayOrNullFromProto(proto.getContractSignature()));
             tradePeer.setPubKeyRing(proto.hasPubKeyRing() ? PubKeyRing.fromProto(proto.getPubKeyRing()) : null);
             tradePeer.setAccountAgeWitnessNonce(ProtoUtil.byteArrayOrNullFromProto(proto.getAccountAgeWitnessNonce()));
             tradePeer.setAccountAgeWitnessSignature(ProtoUtil.byteArrayOrNullFromProto(proto.getAccountAgeWitnessSignature()));

core/src/main/java/haveno/core/trade/protocol/tasks/ArbitratorProcessDepositRequest.java

@@ -24,6 +24,7 @@ import haveno.common.crypto.PubKeyRing;
 import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.offer.Offer;
+import haveno.core.trade.HavenoUtils;
 import haveno.core.trade.Trade;
 import haveno.core.trade.messages.DepositRequest;
 import haveno.core.trade.messages.DepositResponse;
@@ -58,7 +59,7 @@ public class ArbitratorProcessDepositRequest extends TradeTask {
             // get contract and signature
             String contractAsJson = trade.getContractAsJson();
             DepositRequest request = (DepositRequest) processModel.getTradeMessage(); // TODO (woodser): verify response
-            String signature = request.getContractSignature();
+            byte[] signature = request.getContractSignature();
 
             // get trader info
             TradePeer trader = trade.getTradePeer(processModel.getTempTradePeerNodeAddress());
@@ -66,7 +67,9 @@ public class ArbitratorProcessDepositRequest extends TradeTask {
             PubKeyRing peerPubKeyRing = trader.getPubKeyRing();
   
             // verify signature
-            if (!Sig.verify(peerPubKeyRing.getSignaturePubKey(), contractAsJson, signature)) throw new RuntimeException("Peer's contract signature is invalid");
+            if (!HavenoUtils.isSignatureValid(peerPubKeyRing, contractAsJson, signature)) {
+                throw new RuntimeException("Peer's contract signature is invalid");
+            }
 
             // set peer's signature
             trader.setContractSignature(signature);

core/src/main/java/haveno/core/trade/protocol/tasks/BuyerSendPaymentSentMessage.java

@@ -17,10 +17,8 @@
 
 package haveno.core.trade.protocol.tasks;
 
-import com.google.common.base.Charsets;
 import haveno.common.Timer;
 import haveno.common.crypto.PubKeyRing;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.network.MessageState;
 import haveno.core.trade.HavenoUtils;
@@ -94,7 +92,7 @@ public abstract class BuyerSendPaymentSentMessage extends SendMailboxMessageTask
             // sign message
             try {
                 String messageAsJson = JsonUtil.objectToJson(message);
-                byte[] sig = Sig.sign(processModel.getP2PService().getKeyRing().getSignatureKeyPair().getPrivate(), messageAsJson.getBytes(Charsets.UTF_8));
+                byte[] sig = HavenoUtils.sign(processModel.getP2PService().getKeyRing(), messageAsJson);
                 message.setBuyerSignature(sig);
                 processModel.setPaymentSentMessage(message);
                 trade.requestPersistence();

core/src/main/java/haveno/core/trade/protocol/tasks/MaybeSendSignContractRequest.java

@@ -22,11 +22,10 @@ import java.util.Date;
 import java.util.List;
 import java.util.UUID;
 
-import com.google.common.base.Charsets;
 import haveno.common.app.Version;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.trade.ArbitratorTrade;
+import haveno.core.trade.HavenoUtils;
 import haveno.core.trade.MakerTrade;
 import haveno.core.trade.Trade;
 import haveno.core.trade.Trade.State;
@@ -90,7 +89,7 @@ public class MaybeSendSignContractRequest extends TradeTask {
           // maker signs deposit hash nonce to avoid challenge protocol
           byte[] sig = null;
           if (trade instanceof MakerTrade) {
-            sig = Sig.sign(processModel.getP2PService().getKeyRing().getSignatureKeyPair().getPrivate(), depositTx.getHash().getBytes(Charsets.UTF_8));
+            sig = HavenoUtils.sign(processModel.getP2PService().getKeyRing(), depositTx.getHash());
           }
 
           // create request for peer and arbitrator to sign contract

core/src/main/java/haveno/core/trade/protocol/tasks/ProcessSignContractRequest.java

@@ -30,10 +30,10 @@ import haveno.common.crypto.Encryption;
 import haveno.common.crypto.Hash;
 import haveno.common.crypto.PubKeyRing;
 import haveno.common.crypto.ScryptUtil;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.trade.ArbitratorTrade;
 import haveno.core.trade.Contract;
+import haveno.core.trade.HavenoUtils;
 import haveno.core.trade.Trade;
 import haveno.core.trade.Trade.State;
 import haveno.core.trade.messages.SignContractRequest;
@@ -85,7 +85,7 @@ public class ProcessSignContractRequest extends TradeTask {
           // create and sign contract
           Contract contract = trade.createContract();
           String contractAsJson = JsonUtil.objectToJson(contract);
-          String signature = Sig.sign(processModel.getKeyRing().getSignatureKeyPair().getPrivate(), contractAsJson);
+          byte[] signature = HavenoUtils.sign(processModel.getKeyRing(), contractAsJson);
 
           // save contract and signature
           trade.setContract(contract);

core/src/main/java/haveno/core/trade/protocol/tasks/ProcessSignContractResponse.java

@@ -20,8 +20,8 @@ package haveno.core.trade.protocol.tasks;
 
 import haveno.common.app.Version;
 import haveno.common.crypto.PubKeyRing;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
+import haveno.core.trade.HavenoUtils;
 import haveno.core.trade.Trade;
 import haveno.core.trade.messages.DepositRequest;
 import haveno.core.trade.messages.SignContractResponse;
@@ -63,8 +63,8 @@ public class ProcessSignContractResponse extends TradeTask {
 
             // verify signature
             // TODO (woodser): transfer contract for convenient comparison?
-            String signature = response.getContractSignature();
+            byte[] signature = response.getContractSignature();
-            if (!Sig.verify(peerPubKeyRing.getSignaturePubKey(), contractAsJson, signature)) throw new RuntimeException("Peer's contract signature is invalid");
+            if (!HavenoUtils.isSignatureValid(peerPubKeyRing, contractAsJson, signature)) throw new RuntimeException("Peer's contract signature is invalid");
 
             // set peer's signature
             peer.setContractSignature(signature);

core/src/main/java/haveno/core/trade/protocol/tasks/SellerSendPaymentReceivedMessage.java

@@ -22,9 +22,7 @@ import lombok.extern.slf4j.Slf4j;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import com.google.common.base.Charsets;
 import haveno.common.crypto.PubKeyRing;
-import haveno.common.crypto.Sig;
 import haveno.common.taskrunner.TaskRunner;
 import haveno.core.account.sign.SignedWitness;
 import haveno.core.account.witness.AccountAgeWitnessService;
@@ -92,7 +90,7 @@ public abstract class SellerSendPaymentReceivedMessage extends SendMailboxMessag
             // sign message
             try {
                 String messageAsJson = JsonUtil.objectToJson(message);
-                byte[] sig = Sig.sign(processModel.getP2PService().getKeyRing().getSignatureKeyPair().getPrivate(), messageAsJson.getBytes(Charsets.UTF_8));
+                byte[] sig = HavenoUtils.sign(processModel.getP2PService().getKeyRing(), messageAsJson);
                 message.setSellerSignature(sig);
                 processModel.setPaymentReceivedMessage(message);
                 trade.requestPersistence();

desktop/src/main/java/haveno/desktop/main/support/dispute/agent/SignedOfferView.java

@@ -18,6 +18,7 @@
 package haveno.desktop.main.support.dispute.agent;
 
 import haveno.common.UserThread;
+import haveno.common.util.Utilities;
 import haveno.core.locale.Res;
 import haveno.core.offer.OpenOfferManager;
 import haveno.core.offer.SignedOffer;
@@ -379,7 +380,7 @@ public class SignedOfferView extends ActivatableView<VBox, Void> {
                             public void updateItem(final SignedOffer item, boolean empty) {
                                 super.updateItem(item, empty);
                                 if (item != null && !empty)
-                                    setText(item.getArbitratorSignature());
+                                    setText(Utilities.bytesAsHexString(item.getArbitratorSignature()));
                                 else
                                     setText("");
                             }

proto/src/main/proto/pb.proto

@@ -165,7 +165,7 @@ message OfferAvailabilityResponse {
     AvailabilityResult availability_result = 2;
     repeated int32 supported_capabilities = 3;
     string uid = 4;
-    string maker_signature = 5;
+    bytes maker_signature = 5;
 }
 
 message RefreshOfferMessage {
@@ -233,7 +233,7 @@ message InitTradeRequest {
     string reserve_tx_hex = 17;
     string reserve_tx_key = 18;
     string payout_address = 19;
-    string maker_signature = 20;
+    bytes maker_signature = 20;
 }
 
 message InitMultisigRequest {
@@ -261,7 +261,7 @@ message SignContractResponse {
     string uid = 2;
     int64 current_date = 3;
     string contract_as_json = 4;
-    string contract_signature = 5;
+    bytes contract_signature = 5;
     bytes encrypted_payment_account_payload = 6;
 }
 
@@ -269,7 +269,7 @@ message DepositRequest {
     string trade_id = 1;
     string uid = 2;
     int64 current_date = 3;
-    string contract_signature = 4;
+    bytes contract_signature = 4;
     string deposit_tx_hex = 5;
     string deposit_tx_key = 6;
     bytes payment_account_key = 7;
@@ -636,7 +636,7 @@ message OfferPayload {
     int32 protocol_version = 34;
 
     NodeAddress arbitrator_signer = 1001;
-    string arbitrator_signature = 1002;
+    bytes arbitrator_signature = 1002;
     repeated string reserve_tx_key_images = 1003;
 }
 
@@ -696,8 +696,8 @@ message Dispute {
     string deposit_tx_id = 14;
     string payout_tx_id = 15;
     string contract_as_json = 16;
-    string maker_contract_signature = 17;
+    bytes maker_contract_signature = 17;
-    string taker_contract_signature = 18;
+    bytes taker_contract_signature = 18;
     PaymentAccountPayload maker_payment_account_payload = 19;
     PaymentAccountPayload taker_payment_account_payload = 20;
     PubKeyRing agent_pub_key_ring = 21;
@@ -1356,7 +1356,7 @@ message SignedOffer {
     string reserve_tx_hex = 7;
     repeated string reserve_tx_key_images = 8;
     uint64 reserve_tx_miner_fee = 9;
-    string arbitrator_signature = 10;
+    bytes arbitrator_signature = 10;
 }
 
 message OpenOffer {
@@ -1531,7 +1531,7 @@ message ProcessModel {
     int64 funds_needed_for_trade = 7;
     string payment_sent_message_state = 8;
     bool deposits_confirmed_messages_delivered = 9;
-    string maker_signature = 10;
+    bytes maker_signature = 10;
     TradePeer maker = 11;
     TradePeer taker = 12;
     TradePeer arbitrator = 13;
@@ -1557,7 +1557,7 @@ message TradePeer {
     PaymentAccountPayload payment_account_payload = 9;
     string payout_address_string = 10;
     string contract_as_json = 11;
-    string contract_signature = 12;
+    bytes contract_signature = 12;
     bytes account_age_witness_nonce = 18;
     bytes account_age_witness_signature = 19;
     AccountAgeWitness account_age_witness = 20;