fix(drive): bind and bound proof decoding

packages/rs-drive/src/drive/saved_block_transactions/fetch_compacted_address_balances/mod.rs

@@ -8,6 +8,17 @@ use platform_version::version::PlatformVersion;
 
 pub use v0::CompactedAddressBalanceChanges;
 
+/// Proof envelope for compacted address balance changes.
+///
+/// The predecessor proof independently authenticates which range, if any,
+/// contains the requested height. The forward proof can then be verified
+/// against a query derived only from that authenticated result.
+#[derive(Debug, bincode::Encode, bincode::Decode)]
+pub(crate) struct CompactedAddressBalanceProof {
+    pub(crate) predecessor_proof: Vec<u8>,
+    pub(crate) forward_proof: Vec<u8>,
+}
+
 impl Drive {
     /// Fetches compacted address balance changes starting from a given block height.
     ///

packages/rs-drive/src/drive/saved_block_transactions/fetch_compacted_address_balances/v0/mod.rs

@@ -8,6 +8,8 @@ use grovedb::{Element, PathQuery, Query, SizedQuery, TransactionArg};
 use platform_version::version::PlatformVersion;
 use std::collections::BTreeMap;
 
+use super::CompactedAddressBalanceProof;
+
 /// Result type for fetched compacted address balance changes
 /// Each entry is (start_block, end_block, address_balance_map)
 pub type CompactedAddressBalanceChanges = Vec<(
@@ -189,9 +191,11 @@ impl Drive {
 
     /// Version 0 implementation for proving compacted address balance changes.
     ///
-    /// Uses a two-step approach:
-    /// 1. First query (non-proving): descending to find any range containing start_block_height
-    /// 2. Second query (proving): ascending from the found start_block or start_block_height
+    /// Uses two independently verifiable proofs:
+    /// 1. A descending predecessor proof authenticates which range, if any,
+    ///    contains `start_block_height`.
+    /// 2. A forward proof starts at that authenticated range (or at the
+    ///    request-derived fallback key when no range contains the height).
     ///
     /// This ensures the proof covers all relevant ranges efficiently.
     pub(super) fn prove_compacted_address_balance_changes_v0(
@@ -203,7 +207,7 @@ impl Drive {
     ) -> Result<Vec<u8>, Error> {
         let path = Self::saved_compacted_block_transactions_address_balances_path_vec();
 
-        // Step 1: Non-proving descending query to find any range containing start_block_height
+        // Step 1: Authenticate the predecessor used to select the forward query.
         let mut desc_end_key = Vec::with_capacity(16);
         desc_end_key.extend_from_slice(&start_block_height.to_be_bytes());
         desc_end_key.extend_from_slice(&u64::MAX.to_be_bytes());
@@ -222,6 +226,13 @@ impl Drive {
             &platform_version.drive,
         )?;
 
+        let predecessor_proof = self.grove_get_proved_path_query(
+            &desc_path_query,
+            transaction,
+            &mut vec![],
+            &platform_version.drive,
+        )?;
+
         // Determine the actual start key for the proved query
         // If we found a containing range, use its exact key
         // Otherwise use (start_block_height, start_block_height) since end_block >= start_block always
@@ -258,12 +269,27 @@ impl Drive {
 
         let path_query = PathQuery::new(path, SizedQuery::new(query, limit, None));
 
-        self.grove_get_proved_path_query(
+        let forward_proof = self.grove_get_proved_path_query(
             &path_query,
             transaction,
             &mut vec![],
             &platform_version.drive,
+        )?;
+
+        bincode::encode_to_vec(
+            CompactedAddressBalanceProof {
+                predecessor_proof,
+                forward_proof,
+            },
+            bincode::config::standard()
+                .with_big_endian()
+                .with_no_limit(),
         )
+        .map_err(|e| {
+            Error::Protocol(Box::new(ProtocolError::CorruptedSerialization(format!(
+                "cannot encode compacted address balance proof: {e}"
+            ))))
+        })
     }
 }
 

packages/rs-drive/src/drive/saved_block_transactions/mod.rs

@@ -7,4 +7,5 @@ mod store_address_balances;
 
 pub use fetch_address_balances::AddressBalanceChangesPerBlock;
 pub use fetch_compacted_address_balances::CompactedAddressBalanceChanges;
+pub(crate) use fetch_compacted_address_balances::CompactedAddressBalanceProof;
 pub use queries::*;