Bitcoin Testnet4 Transaction Propagation Failure from IC Mainnet

Summary

Bitcoin transactions sent via bitcoin_send_transaction from IC mainnet canisters are accepted by the
Bitcoin Canister but fail to propagate to Bitcoin testnet4 network, despite following DFINITY's official
implementation patterns exactly.

Environment

• Network: Internet Computer Mainnet
• Bitcoin Network: Testnet4
• Canister ID: foxtk-ziaaa-aaaai-atthq-cai
• ic-cdk version: 0.19.0
• rust-bitcoin version: 0.32.7
• Transaction Type: P2WPKH (Pay-to-Witness-Public-Key-Hash)

Problem Description

When executing Bitcoin transfers using the official ic_cdk::bitcoin_canister helper functions,
transactions are:

1. ✅ Successfully built and signed with Chain-Key ECDSA
2. ✅ Accepted by bitcoin_send_transaction() without errors
3. ✅ Return valid TXIDs
4. ❌ Never appear on Bitcoin testnet4 network (verified via mempool.space and block explorers)

Reproduction Steps

Code Implementation (Following DFINITY Pattern)

use ic_cdk::bitcoin_canister::{
    bitcoin_get_utxos, bitcoin_send_transaction,
    GetUtxosRequest, SendTransactionRequest, Network
};

// 1. Get UTXOs
let utxos = bitcoin_get_utxos(&GetUtxosRequest {
    address: from_address.to_string(),
    network: Network::Testnet,  // Maps to testnet4
    filter: None,
}).await?.utxos;

// 2. Build P2WPKH transaction using rust-bitcoin
let signed_tx = /* ... transaction building and signing ... */;

// 3. Send transaction (DFINITY pattern: send BEFORE computing txid)
bitcoin_send_transaction(&SendTransactionRequest {
    network: Network::Testnet,
    transaction: serialize(&signed_tx),
}).await?;

// 4. Compute txid
let txid = signed_tx.compute_txid().to_string();

Test Execution

dfx canister call foxtk-ziaaa-aaaai-atthq-cai request_action '(
  variant {
    Transfer = record {
      chain = "BitcoinTestnet";
      token = "BTC";
      to = "tb1qw508d6qejxtdg4y5r3zarvary0c5xw7kxpjzsx";
      amount = 20000
    }
  }
)' --network ic

Result

variant {
  Executed = record {
    chain = "BitcoinTestnet";
    success = true;
    tx_hash = opt "acf3707ca8b7c05d1c25222ea8eeec6ee7b94ced5f278cd343198f99c287b58c";
  }
}

Evidence of Non-Propagation

Failed Transaction Examples

All transactions were accepted by Bitcoin Canister but never appeared on testnet4:

1. TXID: b8656cc2f7dbc54c0a37b4b02557642b7e5d658cc4495e43b0b21bf65189c81d
  - URL: https://mempool.space/testnet4/tx/b8656cc2f7dbc54c0a37b4b02557642b7e5d658cc4495e43b0b21bf65189c81d
  - Status: "Transaction not found" after 30+ minutes
2. TXID: 645911f1bfdebd6091513cb741e35326c4a837994dc01ba7dc356b93bdd5c43b
  - URL: https://mempool.space/testnet4/tx/645911f1bfdebd6091513cb741e35326c4a837994dc01ba7dc356b93bdd5c43b
  - Status: "Transaction not found" after 30+ minutes
3. TXID: acf3707ca8b7c05d1c25222ea8eeec6ee7b94ced5f278cd343198f99c287b58c (after applying DFINITY pattern
fixes)
  - URL: https://mempool.space/testnet4/tx/acf3707ca8b7c05d1c25222ea8eeec6ee7b94ced5f278cd343198f99c287b58c
  - Status: "Transaction not found" after 15+ minutes

Verified Working Elements

- ✅ Source address has funds: tb1q5pc5mfz2xav022kalwnefe447p9zvnrv8058pa with ~979,466 satoshis
  - Verified: https://mempool.space/testnet4/address/tb1q5pc5mfz2xav022kalwnefe447p9zvnrv8058pa
- ✅ UTXOs retrieved successfully from Bitcoin Canister
- ✅ Transactions properly signed with Chain-Key ECDSA
- ✅ Bitcoin Canister accepts transactions without rejection errors

Investigation Performed

1. Code Pattern Verification

Compared our implementation line-by-line with DFINITY's official examples:
- ✅ rust/basic_bitcoin/src/service/send_from_p2wpkh_address.rs
- ✅ Matches UTXO retrieval pattern
- ✅ Matches transaction building pattern
- ✅ Matches signing pattern
- ✅ Matches bitcoin_send_transaction usage

2. Order of Operations Fix

Changed from computing TXID before sending to DFINITY's recommended pattern (send first, compute after).
Result: No change in propagation behavior.

3. Canister Cycles

Verified canister has sufficient cycles: 1.4 trillion cycles

4. Network Configuration

- Using ic_cdk::bitcoin_canister::Network::Testnet (maps to testnet4 per ICP docs)
- rust-bitcoin Network::Testnet used only for address validation (compatible with testnet4)

Related Issues

- Issue #1288: Similar testnet4 propagation problem with BRC-20 inscriptions
  - Suggests broader testnet4 infrastructure issues

Expected Behavior

Transactions should:
1. Be accepted by Bitcoin Canister
2. Be propagated to Bitcoin testnet4 network via Bitcoin adapters
3. Appear in mempool within 1-5 minutes
4. Be mineable and confirmable

Actual Behavior

Transactions are accepted but never propagate, remaining invisible to:
- mempool.space testnet4 explorer
- Other testnet4 block explorers
- Bitcoin testnet4 nodes

Questions for DFINITY Team

1. Are Bitcoin adapters operational for testnet4 on IC mainnet?
2. Is there a known issue with testnet4 transaction propagation?
3. Should we use testnet3 instead, or is testnet4 fully supported?
4. Are there additional configuration requirements not documented in examples?
5. Is there a way to verify transaction status within the Bitcoin Canister queue?

Workaround Attempts

Tried:
- ❌ Different transaction amounts (10k, 15k, 20k satoshis)
- ❌ Following DFINITY pattern exactly
- ❌ Reinstalling canister with fresh state
- ❌ Waiting 30+ minutes for asynchronous propagation

None resolved the issue.

Request

Please investigate Bitcoin Canister's testnet4 transaction propagation on IC mainnet. This appears to be an
infrastructure issue rather than implementation issue, as the code matches official examples exactly.

Additional Context

- Project: ChainGuard SDK - Multi-chain security middleware for ICP
- Uses official ic-cdk 0.19.0 Bitcoin integration
- Full source available if needed for debugging

Start by reviewing rust/basic_bitcoin/src/service/send_from_p2wpkh_address.rs and reproducing the provided dfx canister call against Bitcoin testnet4. Compare the example's transaction submission path with the reported environment and use the listed transaction IDs and explorer links to determine whether the failure is in the example or testnet4 infrastructure; done means the propagation behavior is explained and an actionable fix or limitation is documented.