diff --git a/src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java b/src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java
index bc49ee5..996456c 100644
--- a/src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java
+++ b/src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java
@@ -576,9 +576,13 @@ public class ECKey {
      * @throws IllegalStateException if this ECKey does not have the private part.
      */
     public String signMessage(String message, ScriptType scriptType) {
+        return signMessage(message, scriptType, this::signEcdsa);
+    }
+
+    public String signMessage(String message, ScriptType scriptType, ECDSAHashSigner ecdsaHashSigner) {
         byte[] data = formatMessageForSigning(message);
         Sha256Hash hash = Sha256Hash.twiceOf(data);
-        ECDSASignature sig = signEcdsa(hash);
+        ECDSASignature sig = ecdsaHashSigner.sign(hash);
         byte recId = findRecoveryId(hash, sig);
         int headerByte = recId + getSigningTypeConstant(scriptType);
         byte[] sigData = new byte[65];  // 1 header + 32 bytes for R + 32 bytes for S
@@ -868,4 +872,8 @@ public class ECKey {
             throw new RuntimeException(e);  // Cannot happen.
         }
     }
+
+    public interface ECDSAHashSigner {
+        ECDSASignature sign(Sha256Hash hash);
+    }
 }
diff --git a/src/main/java/com/sparrowwallet/drongo/wallet/WalletModel.java b/src/main/java/com/sparrowwallet/drongo/wallet/WalletModel.java
index f5fda81..4abf6c5 100644
--- a/src/main/java/com/sparrowwallet/drongo/wallet/WalletModel.java
+++ b/src/main/java/com/sparrowwallet/drongo/wallet/WalletModel.java
@@ -66,6 +66,10 @@ public enum WalletModel {
         return (this == TREZOR_1 || this == KEEPKEY);
     }
 
+    public boolean isCard() {
+        return (this == TAPSIGNER || this == SATSCARD);
+    }
+
     public static WalletModel fromType(String type) {
         for(WalletModel model : values()) {
             if(model.getType().equalsIgnoreCase(type)) {