1. Address: private key -> ECC -> public key compression -> Bech32m encode
2. scriptPubkey: Address -> Bech32m decode -> public key compression
3. Segwit: (dsha256(txid_input & index) * x public key + dsha256(unsigned raw transaction) mod (private key)) mod (N) => Will give a number of 32 bytes
4. Verify:
x1, y1 = ECC(G, dsha256(txid_input & index))
p1 = ECC(G, dsha256(unsigned raw transaction) mod (Segwit))
p2 = ECC((x1,y1) * x public key mod (Segwit)
x2, y2 = ECAddpoint(p1, p2)
If x2 = x public key => OK
I wrote the python code here: https://github.com/tanvovan/bitcoin/blob/main/p2pc.py