diff --git a/src/main/java/org/qortal/transaction/RegisterNameTransaction.java b/src/main/java/org/qortal/transaction/RegisterNameTransaction.java
index 555fcc60..66c1fc8b 100644
--- a/src/main/java/org/qortal/transaction/RegisterNameTransaction.java
+++ b/src/main/java/org/qortal/transaction/RegisterNameTransaction.java
@@ -6,6 +6,7 @@ import java.util.List;
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
 import org.qortal.block.BlockChain;
+import org.qortal.crypto.Crypto;
 import org.qortal.data.transaction.RegisterNameTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.naming.Name;
@@ -62,6 +63,10 @@ public class RegisterNameTransaction extends Transaction {
 		if (!name.equals(Unicode.normalize(name)))
 			return ValidationResult.NAME_NOT_NORMALIZED;
 
+		// Check name doesn't look like an address
+		if (Crypto.isValidAddress(name))
+			return ValidationResult.INVALID_ADDRESS;
+
 		// Check registrant has enough funds
 		if (registrant.getConfirmedBalance(Asset.QORT) < this.registerNameTransactionData.getFee())
 			return ValidationResult.NO_BALANCE;
diff --git a/src/main/java/org/qortal/transaction/UpdateNameTransaction.java b/src/main/java/org/qortal/transaction/UpdateNameTransaction.java
index fdcba164..ebfde97c 100644
--- a/src/main/java/org/qortal/transaction/UpdateNameTransaction.java
+++ b/src/main/java/org/qortal/transaction/UpdateNameTransaction.java
@@ -5,6 +5,7 @@ import java.util.List;
 
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
+import org.qortal.crypto.Crypto;
 import org.qortal.data.naming.NameData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.UpdateNameTransactionData;
@@ -77,6 +78,10 @@ public class UpdateNameTransaction extends Transaction {
 			// Check new name is in normalized form (no leading/trailing whitespace, etc.)
 			if (!newName.equals(Unicode.normalize(newName)))
 				return ValidationResult.NAME_NOT_NORMALIZED;
+
+			// Check name doesn't look like an address
+			if (Crypto.isValidAddress(newName))
+				return ValidationResult.INVALID_ADDRESS;
 		}
 
 		// Check new data size bounds (0 length means don't update data)
diff --git a/src/main/java/org/qortal/utils/Unicode.java b/src/main/java/org/qortal/utils/Unicode.java
index 8a9092ea..b73f3a32 100644
--- a/src/main/java/org/qortal/utils/Unicode.java
+++ b/src/main/java/org/qortal/utils/Unicode.java
@@ -41,7 +41,7 @@ public abstract class Unicode {
 		buildHomoglyphCodePointArrays();
 	}
 
-	/** Returns string in Unicode canonical normalized form (NFC),<br>
+	/** Returns string in Unicode canonical normalized form (NFKC),<br>
 	 * with zero-width spaces/joiners removed,<br>
 	 * leading/trailing whitespace trimmed<br>
 	 * and all other whitespace blocks collapsed into a single space character.
diff --git a/src/test/java/org/qortal/test/naming/MiscTests.java b/src/test/java/org/qortal/test/naming/MiscTests.java
index 0bb750d0..c46cbfab 100644
--- a/src/test/java/org/qortal/test/naming/MiscTests.java
+++ b/src/test/java/org/qortal/test/naming/MiscTests.java
@@ -96,4 +96,46 @@ public class MiscTests extends Common {
 		}
 	}
 
+	// test trying to register a name that looks like an address
+	@Test
+	public void testRegisterAddressAsName() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Register-name
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			String name = alice.getAddress();
+			String data = "{}";
+
+			RegisterNameTransactionData transactionData = new RegisterNameTransactionData(TestTransaction.generateBase(alice), name, data);
+			Transaction transaction = Transaction.fromData(repository, transactionData);
+			transaction.sign(alice);
+
+			ValidationResult result = transaction.importAsUnconfirmed();
+			assertTrue("Transaction should be invalid", ValidationResult.OK != result);
+		}
+	}
+
+	// test register then trying to update to a name that looks like an address
+	@Test
+	public void testUpdateToAddressAsName() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			// Register-name
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			String name = "test-name";
+			String data = "{}";
+
+			TransactionData transactionData = new RegisterNameTransactionData(TestTransaction.generateBase(alice), name, data);
+			TransactionUtils.signAndMint(repository, transactionData, alice);
+
+			// we shouldn't be able to update name to an address
+			String newName = alice.getAddress();
+			String newData = "";
+			transactionData = new UpdateNameTransactionData(TestTransaction.generateBase(alice), name, newName, newData);
+			Transaction transaction = Transaction.fromData(repository, transactionData);
+			transaction.sign(alice);
+
+			ValidationResult result = transaction.importAsUnconfirmed();
+			assertTrue("Transaction should be invalid", ValidationResult.OK != result);
+		}
+	}
+
 }