feat (HIP-540): Change Or Remove Existing Keys From A Token (#1803)

Signed-off-by: Nikita Lebedev <[email protected]>

examples/README.md

@@ -53,6 +53,7 @@
 * [Custom fees (exempt)](../examples/src/main/java/ExemptCustomFeesExample.java)
 * [NFT Allowances](../examples/src/main/java/NftAddRemoveAllowancesExample.java)
 * [Zero token operations](../examples/src/main/java/ZeroTokenOperationsExample.java)
+* [Change Or Remove Existing Keys From A Token (HIP-540)](../examples/src/main/java/ChangeRemoveTokenKeys.java)
 
 ### File Service
 * [Create a file](../examples/src/main/java/CreateFileExample.java)

examples/src/main/java/ChangeRemoveTokenKeys.java

@@ -0,0 +1,147 @@
+import com.hedera.hashgraph.sdk.AccountId;
+import com.hedera.hashgraph.sdk.Client;
+import com.hedera.hashgraph.sdk.KeyList;
+import com.hedera.hashgraph.sdk.PrivateKey;
+import com.hedera.hashgraph.sdk.PublicKey;
+import com.hedera.hashgraph.sdk.TokenCreateTransaction;
+import com.hedera.hashgraph.sdk.TokenInfoQuery;
+import com.hedera.hashgraph.sdk.TokenKeyValidation;
+import com.hedera.hashgraph.sdk.TokenType;
+import com.hedera.hashgraph.sdk.TokenUpdateTransaction;
+import io.github.cdimascio.dotenv.Dotenv;
+import java.util.Objects;
+
+public class ChangeRemoveTokenKeys {
+
+    // see `.env.sample` in the repository root for how to specify these values
+    // or set environment variables with the same names
+    private static final AccountId OPERATOR_ID = AccountId.fromString(Objects.requireNonNull(Dotenv.load().get("OPERATOR_ID")));
+
+    private static final PrivateKey OPERATOR_KEY = PrivateKey.fromString(Objects.requireNonNull(Dotenv.load().get("OPERATOR_KEY")));
+
+    // HEDERA_NETWORK defaults to testnet if not specified in dotenv
+    private static final String HEDERA_NETWORK = Dotenv.load().get("HEDERA_NETWORK", "testnet");
+
+    private ChangeRemoveTokenKeys() {
+    }
+
+    public static void main(String[] args) throws Exception {
+        Client client = ClientHelper.forName(HEDERA_NETWORK);
+
+        // Defaults the operator account ID and key such that all generated transactions will be paid for
+        // by this account and be signed by this key
+        client.setOperator(OPERATOR_ID, OPERATOR_KEY);
+
+        // Admin, Supply, Wipe keys
+        var adminKey = PrivateKey.generateED25519();
+        var supplyKey = PrivateKey.generateED25519();
+        var newSupplyKey = PrivateKey.generateED25519();
+        var wipeKey = PrivateKey.generateED25519();
+
+        // This HIP introduces ability to remove lower-privilege keys (Wipe, KYC, Freeze, Pause, Supply, Fee Schedule, Metadata) from a Token:
+        // - using an update with the empty KeyList;
+        var emptyKeyList = new KeyList();
+
+        // create a non-fungible token
+        var tokenId = Objects.requireNonNull(
+            new TokenCreateTransaction()
+                .setTokenName("Example NFT")
+                .setTokenSymbol("ENFT")
+                .setTokenType(TokenType.NON_FUNGIBLE_UNIQUE)
+                .setTreasuryAccountId(OPERATOR_ID)
+                .setAdminKey(adminKey.getPublicKey())
+                .setWipeKey(wipeKey.getPublicKey())
+                .setSupplyKey(supplyKey.getPublicKey())
+                .freezeWith(client)
+                .sign(adminKey)
+                .execute(client)
+                .getReceipt(client)
+                .tokenId
+        );
+
+        var tokenInfoBefore = new TokenInfoQuery()
+            .setTokenId(tokenId)
+            .execute(client);
+
+        System.out.println("Admin Key:" + tokenInfoBefore.adminKey);
+        System.out.println("Supply Key:" + tokenInfoBefore.supplyKey);
+        System.out.println("Wipe Key:" + tokenInfoBefore.wipeKey);
+
+        System.out.println("---");
+        System.out.println("Removing Wipe Key...");
+
+        new TokenUpdateTransaction()
+            .setTokenId(tokenId)
+            .setWipeKey(emptyKeyList)
+            .setKeyVerificationMode(TokenKeyValidation.FULL_VALIDATION) // it is by default, but we set explicitly for illustration
+            .freezeWith(client)
+            .sign(adminKey)
+            .execute(client)
+            .getReceipt(client);
+
+        var tokenInfoAfterWipeKeyRemoval = new TokenInfoQuery()
+            .setTokenId(tokenId)
+            .execute(client);
+
+        System.out.println("Wipe Key (after removal):" + tokenInfoAfterWipeKeyRemoval.wipeKey);
+
+        System.out.println("---");
+        System.out.println("Removing Admin Key...");
+
+        new TokenUpdateTransaction()
+            .setTokenId(tokenId)
+            .setAdminKey(emptyKeyList)
+            .setKeyVerificationMode(TokenKeyValidation.NO_VALIDATION)
+            .freezeWith(client)
+            .sign(adminKey)
+            .execute(client)
+            .getReceipt(client);
+
+        var tokenInfoAfterAdminKeyRemoval = new TokenInfoQuery()
+            .setTokenId(tokenId)
+            .execute(client);
+
+        System.out.println("Admin Key (after removal):" + tokenInfoAfterAdminKeyRemoval.adminKey);
+
+        System.out.println("---");
+        System.out.println("Updating Supply Key...");
+
+        new TokenUpdateTransaction()
+            .setTokenId(tokenId)
+            .setSupplyKey(newSupplyKey)
+            .setKeyVerificationMode(TokenKeyValidation.FULL_VALIDATION)
+            .freezeWith(client)
+            .sign(supplyKey)
+            .sign(newSupplyKey)
+            .execute(client)
+            .getReceipt(client);
+
+        var tokenInfoAfterSupplyKeyUpdate = new TokenInfoQuery()
+            .setTokenId(tokenId)
+            .execute(client);
+
+        System.out.println("Supply Key (after update):" + tokenInfoAfterSupplyKeyUpdate.supplyKey);
+
+        System.out.println("---");
+        System.out.println("Removing Supply Key...");
+
+        new TokenUpdateTransaction()
+            .setTokenId(tokenId)
+            .setSupplyKey(PublicKey.unusableKey())
+            .setKeyVerificationMode(TokenKeyValidation.NO_VALIDATION)
+            .freezeWith(client)
+            .sign(newSupplyKey)
+            .execute(client)
+            .getReceipt(client);
+
+        var tokenInfoAfterSupplyKeyRemoval = new TokenInfoQuery()
+            .setTokenId(tokenId)
+            .execute(client);
+
+        var supplyKeyAfterRemoval = (PublicKey) tokenInfoAfterSupplyKeyRemoval.supplyKey;
+
+        System.out.println("Supply Key (after removal):" + supplyKeyAfterRemoval.toStringRaw());
+
+        client.close();
+    }
+}