Helper functions for the bridge

[ekrembal]

• winternitz_sig_check<D, N>(PublicKey[N], XOnlyPublicKey) -> ScriptBuf: This should verify the winternitz signature, and do: xonly_pk OP_CHECKSIG at the end.
• double_winternitz_sig_check<D, N>(PublicKey[2; N], XOnlyPublicKey) -> ScriptBuf: This should verify the winternitz signature for both PublicKey and verify that signed messages are same, and do: xonly_pk OP_CHECKSIG at the end.
• bitvm(D, N, winternitz_pks: PublicKey[], prover_xonly_pk: XOnlyPublicKey, nofn_xonly_pk XOnlyPublicKey, public_inputs_winternitz_pks: (PublicKey[], Digest)[] ) -> (ScriptHash[], ScriptHash[]): This should return the array of assertTx script hashes and disprove script hases, where public_inputs_winternitz_pks are hashed and the resulting hash is the public input of the groth16 proof. Prover's xonly pubkey and N-of-N xonly pubkey is given.

Afther these we can implement disprove txs