# For CLI user
cargo install bithoven
# For rust user
cargo add bithoven
# For js user
npm install bithoven

pragma bithoven version 0.0.1;
pragma bithoven target segwit;

/* * Stack Input Definitions
 * Each line defines a valid input stack configuration for a spending path.
 */
(condition: bool, sig_alice: signature)
(condition: bool, preimage: string, sig_bob: signature)

{
    // If 'condition' is true, we enter the Refund Path (Alice)
    if condition {
        // Enforce relative timelock of 1000 blocks
        older 1000;

        // If timelock is satisfied, Alice can spend with her signature
        return checksig(sig_alice, "0245a6b3f8eeab8e88501a9a25391318dce9bf35e24c377ee82799543606bf5212");

    } else {
        // Redeem Path (Bob)
        // Bob must reveal the secret preimage that hashes to the expected value
        verify sha256(sha256(preimage)) == "53de742e2e323e3290234052a702458589c30d2c813bf9f866bef1b651c4e45f";

        // If hash matches, Bob can spend with his signature
        return checksig(sig_bob, "0345a6b3f8eeab8e88501a9a25391318dce9bf35e24c377ee82799543606bf5212");
    }
}

bithoven compile htlc.bithoven

OP_IF
    <0xe803> OP_CHECKSEQUENCEVERIFY OP_DROP
    <pubkey_alice> OP_CHECKSIG
OP_ELSE
    OP_HASH256 OP_TOALTSTACK <hash_digest> OP_FROMALTSTACK OP_SWAP OP_EQUALVERIFY
    <pubkey_bob> OP_CHECKSIG
OP_ENDIF

@misc{bithoven,
      title={Bithoven: Formal Safety for Expressive Bitcoin Smart Contracts}, 
      author={Hyunhum Cho and Ik Rae Jeong},
      year={2026},
      eprint={2601.01436},
      archivePrefix={arXiv},
      primaryClass={cs.CR},
      url={https://arxiv.org/abs/2601.01436}, 
}