Module payment 

BIP70: Payment Protocol (P2P Variant)

Specification: https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki

This is a P2P-based variant of BIP70 that addresses security concerns:

• Uses Bitcoin P2P network instead of HTTP/HTTPS (privacy-preserving)
• Uses Bitcoin public key signatures instead of X.509 certificates (decentralized)
• Supports signed refund addresses (prevents refund attacks)
• Works with TCP, Iroh, and QUIC transports

Core messages:

• PaymentRequest: Merchant payment details signed with Bitcoin key
• Payment: Customer payment transaction(s)
• PaymentACK: Merchant confirmation of payment

Security enhancements:

• Merchant authentication via Bitcoin public keys (on-chain verifiable)
• Signed refund addresses prevent refund attacks
• P2P routing preserves customer privacy (no direct merchant connection)

Structs

CovenantProof

CTV covenant proof for payment commitment

Payment

Payment - Customer payment transaction(s)

PaymentACK

Payment ACK - Merchant confirmation

PaymentDetails

Payment Details - Core payment information

PaymentOutput

Payment Output - Address and amount

PaymentProtocolClient

BIP70 Payment Protocol client (for making payments via P2P)

PaymentProtocolServer

BIP70 Payment Protocol server (for receiving payments via P2P)

PaymentRequest

Payment Request - Main payment protocol message

SignedRefundAddress

Signed refund address - Pre-authorized refund address with merchant signature

TemplateInput

Template input (CTV format: no scriptSig)

TemplateOutput

Template output

TransactionTemplate

Transaction template for CTV (without scriptSig)

Enums

Bip70Error

BIP70 Error types

SettlementStatus

Settlement status for payment

Constants

PAYMENT_PROTOCOL_VERSION

BIP70 Payment Protocol version