Public-mode Spark exposes exact balances, leaf ownership, and raw Bitcoin transaction material

What the evidence shows

Technical and product details

1. Documented behavior

   Spark's policy classifies node and balance queries as unauthenticated. The official read-only SDK exposes a createPublic client with authentication mode none. 12

   Supporting material shown on this page

   unauthenticated read policyPinned source code · github.com · checked 2026-07-14

   151		pbspark.SparkService_QueryUserSignedRefunds_FullMethodName:              {AuthMode: AuthSession},
   152		pbspark.SparkService_QueryUnusedDepositAddresses_FullMethodName:         {AuthMode: AuthUnauthenticated},
   153		pbspark.SparkService_QueryStaticDepositAddresses_FullMethodName:         {AuthMode: AuthUnauthenticated},
   154		pbspark.SparkService_SubscribeToEvents_FullMethodName:                   {AuthMode: AuthSession},
   155		pbspark.SparkService_InitiateStaticDepositUtxoRefund_FullMethodName:     {AuthMode: AuthSession},
   156		pbspark.SparkService_ExitSingleNodeTrees_FullMethodName:                 {AuthMode: AuthSession},
   157		pbspark.SparkService_CooperativeExitV2_FullMethodName:                   {AuthMode: AuthSession},

   public read-only client and balance queryPinned source code · github.com · checked 2026-07-14

   160      this.config.getCoordinatorAddress(),
   161    );
   162
   163    try {
   164      return await this.queryNodeBalance(sparkClient, identityPublicKey, [
   165        TreeNodeStatus.TREE_NODE_STATUS_AVAILABLE,
   166      ]);

2. Documented behavior

   Given a Spark address, getAvailableBalance resolves its identity key, enumerates the wallet's readable leaves, and sums their exact satoshi values. 23

   Supporting material shown on this page

   public read-only client and balance queryPinned source code · github.com · checked 2026-07-14

   160      this.config.getCoordinatorAddress(),
   161    );
   162
   163    try {
   164      return await this.queryNodeBalance(sparkClient, identityPublicKey, [
   165        TreeNodeStatus.TREE_NODE_STATUS_AVAILABLE,
   166      ]);

   privacy-filtered node enumerationPinned source code · github.com · checked 2026-07-14

   74			return nil, errors.InvalidArgumentMalformedKey(fmt.Errorf("failed to parse owner identity public key: %w", err))
   75		}
   76		if !isSSP {
   77			hasReadAccess, err := NewWalletSettingHandler(h.config).HasReadAccessToWallet(ctx, ownerIdentityPubKey)
   78			if err != nil {
   79				return nil, fmt.Errorf("failed to check if privacy is enabled for owner: %w", err)
   80			}

3. Documented behavior

   Returned node records include exact value, owner identity and signing keys, tree and parent relationships, status and timestamps, plus raw node, refund, direct, direct-refund, and direct-from-CPFP-refund transactions. 4

   Supporting material shown on this page

   returned node fieldsPinned source code · github.com · checked 2026-07-14

   46	}
   47	return &pbspark.TreeNode{
   48		Id:                     tn.ID.String(),
   49		TreeId:                 treeIDStr,
   50		Value:                  tn.Value,
   51		ParentNodeId:           tn.getParentNodeID(ctx),
   52		NodeTx:                 tn.RawTx,

Scope control

What this does not establish

• The observer must first know the Spark address, identity key, or node IDs. Enforced privacy mode can suppress covered queries. Raw transactions are not private keys and do not themselves confer spending authority. 234

Sources and excerpts

Primary sources

The relevant details and available source-code excerpts appear alongside the claims above. This list preserves the complete original-source trail for independent verification.