diff --git a/lib/rouge.mjs b/lib/rouge.mjs
index c2f6964..4383463 100644
--- a/lib/rouge.mjs
+++ b/lib/rouge.mjs
@@ -92,7 +92,7 @@ export const calculateStampProof = async ({ contract, signer, secret, tokenId, c
   trace('[calculateStampProof OUT]', { channelId, secretHash, salt, index })
   // XXX trace wrong secret ?
   // console.log('MAIN LIB', `${chainId}:${contract.address}:${channelId}:${secretHash}:${salt}:${index}`)
-  return ethers.id(`${chainId}:${contract.address}:${channelId}:${secretHash}:${salt}:${index}`)
+  return ethers.id(`${chainId}:${await contract.getAddress()}:${channelId}:${secretHash}:${salt}:${index}`)
 }
 
 export const encodeAnnotatedProof = ({ contract, bearer, tokenId, proof }) => {
@@ -156,11 +156,12 @@ export const abiEncodeAcquire = async ({ channels, signer, secret, contract, acq
   let index = 1
   let nativeTotal = 0n
   // throw if twice same channelId => also solidityCheck ?
+  const contractAddress = await contract.getAddress()
   const loop = ({ channelId, qty = 1 } = {}, i) => {
     // XXX check uint8 qty, uint16 channelId ?
     const stamps = []
     for (let i = 1; i <= qty; i++) {
-      const proof = ethers.id(`${chainId}:${contract.address}:${channelId}:${secretHash}:${salt}:${index}`)
+      const proof = ethers.id(`${chainId}:${contractAddress}:${channelId}:${secretHash}:${salt}:${index}`)
       trace('[abiEncodeAcquire]', { channelId, qty, index: i, proof })
       stamps.push(getStamp(proof))
       index++;