diff --git a/creator-keys/tests/pause_blocks_buy_sell_integration.rs b/creator-keys/tests/pause_blocks_buy_sell_integration.rs
new file mode 100644
index 00000000..9d526c3a
--- /dev/null
+++ b/creator-keys/tests/pause_blocks_buy_sell_integration.rs
@@ -0,0 +1,102 @@
+//! Integration test for issue #643.
+//!
+//! Scope:
+//!   - Initialize the contract and pause it via the admin pause function
+//!   - Invoke buy and assert the transaction reverts with the paused error code
+//!   - Invoke sell and assert it also reverts with the paused error code
+//!   - Unpause the contract and assert a subsequent buy succeeds
+//!   - Assert no supply or balance changes occur while the contract is paused
+
+mod contract_test_env;
+
+use contract_test_env::{
+    register_creator_keys, register_test_creator, set_pricing_and_fees, test_env_with_auths,
+};
+use creator_keys::ContractError;
+use soroban_sdk::{testutils::Address as _, Address};
+
+const KEY_PRICE: i128 = 1_000;
+const CREATOR_BPS: u32 = 9_000;
+const PROTOCOL_BPS: u32 = 1_000;
+
+#[test]
+fn test_buy_and_sell_revert_while_paused_then_buy_succeeds_after_unpause() {
+    let env = test_env_with_auths();
+    let (client, _) = register_creator_keys(&env);
+    set_pricing_and_fees(&env, &client, KEY_PRICE, CREATOR_BPS, PROTOCOL_BPS);
+
+    let admin = Address::generate(&env);
+    client.set_protocol_admin(&admin, &admin);
+
+    let creator = register_test_creator(&env, &client, "alice");
+    let buyer = Address::generate(&env);
+
+    // Baseline: one key purchased before pausing so sell has something to act on.
+    let quote = client.get_buy_quote(&creator);
+    client.buy_key(&creator, &buyer, &quote.total_amount, &None);
+
+    let supply_before_pause = client.get_total_key_supply(&creator);
+    let balance_before_pause = client.get_key_balance(&creator, &buyer);
+    assert_eq!(supply_before_pause, 1);
+    assert_eq!(balance_before_pause, 1);
+
+    // --- Pause the contract via the admin function ---
+    client.pause(&admin);
+    assert!(client.get_is_paused());
+
+    // --- buy reverts with the paused error code while paused ---
+    let buy_quote_while_paused = client.get_buy_quote(&creator);
+    let buy_result = client.try_buy_key(
+        &creator,
+        &buyer,
+        &buy_quote_while_paused.total_amount,
+        &None,
+    );
+    assert_eq!(
+        buy_result,
+        Err(Ok(ContractError::ProtocolPaused)),
+        "buy must revert with ProtocolPaused while contract is paused"
+    );
+
+    // --- sell reverts with the paused error code while paused ---
+    let sell_result = client.try_sell_key(&creator, &buyer, &None);
+    assert_eq!(
+        sell_result,
+        Err(Ok(ContractError::ProtocolPaused)),
+        "sell must revert with ProtocolPaused while contract is paused"
+    );
+
+    // --- No supply or balance changes occur while paused ---
+    assert_eq!(
+        client.get_total_key_supply(&creator),
+        supply_before_pause,
+        "supply must be unchanged after failed buy/sell attempts while paused"
+    );
+    assert_eq!(
+        client.get_key_balance(&creator, &buyer),
+        balance_before_pause,
+        "buyer balance must be unchanged after failed buy/sell attempts while paused"
+    );
+
+    // --- Unpause the contract ---
+    client.unpause(&admin);
+    assert!(!client.get_is_paused());
+
+    // --- A subsequent buy succeeds after unpausing ---
+    let quote_after_unpause = client.get_buy_quote(&creator);
+    let new_supply = client.buy_key(&creator, &buyer, &quote_after_unpause.total_amount, &None);
+
+    assert_eq!(
+        new_supply,
+        supply_before_pause + 1,
+        "buy after unpause must succeed and increment supply by exactly 1"
+    );
+    assert_eq!(
+        client.get_total_key_supply(&creator),
+        supply_before_pause + 1
+    );
+    assert_eq!(
+        client.get_key_balance(&creator, &buyer),
+        balance_before_pause + 1
+    );
+}