Add user defined script as part of multisig

README.md

@@ -22,7 +22,7 @@ Each component of the project has its own README file with more detailed informa
 
 ## Web Demo
 
-A live testnet demo is hosted at **[testnet.simplicity-unchained.blockstream.com](https://testnet.simplicity-unchained.blockstream.com/)**. It provides a browser interface for writing Simplicity programs, compiling them, generating a P2WSH address, and sending co-signed transactions on Bitcoin Testnet4 or Liquid Testnet — no CLI or local setup required.
+A live testnet demo is hosted at **[testnet.simplicity-unchained.blockstream.com](https://testnet.simplicity-unchained.blockstream.com/)**. It provides a browser interface for writing Simplicity programs, compiling them, generating a P2TR address, and sending co-signed transactions on Bitcoin Testnet4 or Liquid Testnet — no CLI or local setup required.
 
 ![Simplicity Unchained Web Demo](doc/demo_website.png)
 
@@ -33,7 +33,7 @@ A live testnet demo is hosted at **[testnet.simplicity-unchained.blockstream.com
 You can explore the Bitcoin capabilities by running the [Bitcoin demo script](cli/scripts/demo_bitcoin.sh). This demo guides you through:
 
 1. Tweaking a public key with a Simplicity program via the Simplicity Unchained service.
-2. Creating a 2-of-2 multisig P2SH, P2WSH or P2TR address on Bitcoin regtest.
+2. Creating a 2-of-2 multisig P2TR address on Bitcoin regtest.
 3. Funding the address and creating a PSBT spending transaction.
 4. Using the Simplicity Unchained service to co-sign the PSBT after successful Simplicity program execution.
 5. Broadcasting the fully signed transaction to Bitcoin regtest.

cli/scripts/demo_btc.sh

@@ -0,0 +1,155 @@
+#!/bin/bash
+
+set -e
+
+echo "==== Spend type: P2TR ===="
+echo
+
+BTC="bitcoin-cli -regtest"
+PROGRAM="zSQIS29W33fvVt9371bfd+9W33fvVt9371bfd+9W33fvVt93hgGA"
+SIMPLICITY_WITNESS=""
+NETWORK="regtest"
+CSV_BLOCKS=10
+
+echo "==== Sanity checks ===="
+if ! command -v bitcoin-cli &> /dev/null; then
+  echo "ERROR: bitcoin-cli not found in PATH"
+  exit 1
+fi
+
+if ! $BTC getblockchaininfo > /dev/null 2>&1; then
+  echo "ERROR: bitcoind is not running or not reachable."
+  echo "Start it with:"
+  echo "  bitcoind -regtest -fallbackfee=0.0002 -txindex=1 -daemon"
+  echo "  bitcoin-cli -regtest loadwallet <wallet>"
+  exit 1
+fi
+
+echo "OK — bitcoind running"
+echo
+
+echo "==== Setup: Ensure wallet has funds ===="
+MINER_ADDR=$($BTC getnewaddress)
+BAL=$($BTC getbalance)
+if (( $(echo "$BAL < 1.0" | bc -l) )); then
+  echo "Mining initial coins..."
+  $BTC generatetoaddress 101 "$MINER_ADDR" > /dev/null
+fi
+echo "Wallet balance: $($BTC getbalance) BTC"
+echo
+
+echo "==== Step 0: Get Tweaked Cosigner Public Key ===="
+TWEAK_RESPONSE=$(curl -s -X POST http://localhost:30431/simplicity-unchained/tweak \
+  -H "Content-Type: application/json" \
+  -d "$(jq -n --arg program "$PROGRAM" '{program: $program, jet_env: "bitcoin"}')")
+
+COSIGNER_PUBKEY=$(echo "$TWEAK_RESPONSE" | jq -r '.tweaked_public_key_hex')
+if [ -z "$COSIGNER_PUBKEY" ] || [ "$COSIGNER_PUBKEY" = "null" ]; then
+  echo "ERROR: Failed to get tweaked public key"
+  echo "Response: $TWEAK_RESPONSE"
+  exit 1
+fi
+echo "Cosigner pubkey: $COSIGNER_PUBKEY"
+echo
+
+echo "==== Step 1: Generate User Keypair ===="
+USER_KEYPAIR=$(cargo run --quiet -- keypair generate)
+USER_SECKEY=$(echo "$USER_KEYPAIR" | jq -r '.secret_key')
+USER_PUBKEY=$(echo "$USER_KEYPAIR" | jq -r '.public_key')
+echo "User public key: $USER_PUBKEY"
+echo
+
+echo "==== Step 2: Build User Leaf (CSV recovery) ===="
+cargo run --quiet -- btc-tx build-csv-leaf --user-pubkey "$USER_PUBKEY" --timelock "$CSV_BLOCKS"
+LEAF_DATA=$(cargo run --quiet -- btc-tx build-csv-leaf \
+  --user-pubkey "$USER_PUBKEY" \
+  --timelock "$CSV_BLOCKS")
+USER_LEAF_HASH=$(echo "$LEAF_DATA" | jq -r '.leaf_hash')
+echo "User leaf hash:   $USER_LEAF_HASH"
+echo
+
+echo "==== Step 3: Create P2TR Address ===="
+ADDRESS_DATA=$(cargo run --quiet -- address multisig \
+  --pubkey1 "$COSIGNER_PUBKEY" \
+  --pubkey2 "$USER_PUBKEY" \
+  --user-leaf-hash "$USER_LEAF_HASH" \
+  --network "$NETWORK")
+
+ADDRESS=$(echo "$ADDRESS_DATA" | jq -r '.address')
+if [ -z "$ADDRESS" ] || [ "$ADDRESS" = "null" ]; then
+  echo "ERROR: Failed to generate address"
+  echo "Response: $ADDRESS_DATA"
+  exit 1
+fi
+echo "Address: $ADDRESS"
+echo
+
+echo "==== Step 4: Fund Address ===="
+FUNDING_TXID=$($BTC sendtoaddress "$ADDRESS" 0.001)
+$BTC generatetoaddress 1 "$MINER_ADDR" > /dev/null
+echo "Funding txid: $FUNDING_TXID (confirmed)"
+VOUT=$($BTC gettransaction "$FUNDING_TXID" | jq '.details[0].vout')
+echo "Output index: $VOUT"
+echo
+
+echo "==== Step 5: Create PSBT ===="
+PSBT_CREATE_DATA=$(cargo run --quiet -- btc-tx create \
+  -i "$FUNDING_TXID:$VOUT" \
+  -o "$ADDRESS:90000" \
+  --network "$NETWORK")
+PSBT_HEX=$(echo "$PSBT_CREATE_DATA" | jq -r '.psbt')
+echo "Created PSBT: $PSBT_HEX"
+echo
+
+echo "==== Step 6: Cosigner Signature (Service) ===="
+SIGN_REQUEST=$(jq -n \
+  --arg psbt "$PSBT_HEX" \
+  --arg program "$PROGRAM" \
+  --arg witness "$SIMPLICITY_WITNESS" \
+  --arg user_pubkey "$USER_PUBKEY" \
+  --arg user_leaf_hash "$USER_LEAF_HASH" \
+  '{
+    psbt_hex: $psbt,
+    input_index: 0,
+    program: $program,
+    witness: $witness,
+    jet_env: "bitcoin",
+    user_pubkey: $user_pubkey,
+    user_leaf_hash_hex: $user_leaf_hash
+  }')
+
+PSBT_SIGN1_DATA=$(curl -s -X POST http://localhost:30431/simplicity-unchained/sign/psbt \
+  -H "Content-Type: application/json" \
+  -d "$SIGN_REQUEST")
+
+if echo "$PSBT_SIGN1_DATA" | jq -e '.error' > /dev/null 2>&1; then
+  echo "ERROR from sign service: $(echo "$PSBT_SIGN1_DATA" | jq -r '.error')"
+  exit 1
+fi
+
+PSBT_SIGNED1=$(echo "$PSBT_SIGN1_DATA" | jq -r '.psbt_hex')
+echo "Cosigner signature: $(echo "$PSBT_SIGN1_DATA" | jq -r '.signature_hex')"
+echo
+
+echo "==== Step 7: User Signature ===="
+PSBT_SIGN2_DATA=$(cargo run --quiet -- btc-tx sign \
+  --psbt "$PSBT_SIGNED1" \
+  --secret-key "$USER_SECKEY" \
+  --input-index 0 \
+  --cosigner-pubkey "$COSIGNER_PUBKEY" \
+  --user-leaf-hash "$USER_LEAF_HASH")
+
+PSBT_SIGNED2=$(echo "$PSBT_SIGN2_DATA" | jq -r '.psbt')
+echo "User signature added"
+echo
+
+echo "==== Step 8: Finalize ===="
+FINALIZE_DATA=$(cargo run --quiet -- btc-tx finalize --psbt "$PSBT_SIGNED2")
+FINAL_TX_HEX=$(echo "$FINALIZE_DATA" | jq -r '.transaction_hex')
+echo "TXID: $(echo "$FINALIZE_DATA" | jq -r '.txid')"
+echo
+
+echo "==== Step 9: Broadcast ===="
+BROADCAST_TXID=$($BTC sendrawtransaction "$FINAL_TX_HEX")
+$BTC generatetoaddress 1 "$MINER_ADDR" > /dev/null
+echo "Done! TXID: $BROADCAST_TXID"