diff --git a/bzz/bzzcontract/swarm.sol b/bzz/bzzcontract/swarm.sol
new file mode 100644
index 0000000000..89ec700bb0
--- /dev/null
+++ b/bzz/bzzcontract/swarm.sol
@@ -0,0 +1,29 @@
+contract Swarm
+{
+
+  struct Bee {
+    uint deposit;
+    uint expiry;
+  }
+
+  mapping (address => Bee) swarm;
+
+  function max(uint a, uint b) private returns (uint c) {
+    if(a >= b) return a;
+    return b;
+  }
+
+  function signup(uint time) {
+    Bee b = swarm[msg.sender];
+    b.expiry = max(b.expiry, now) + time;
+    b.deposit += msg.value;
+  }
+
+  function withdraw() {
+    Bee b = swarm[msg.sender];
+    if(now > b.expiry) {
+	msg.sender.send(b.deposit);
+    }
+  }
+
+}