Payment Protocol: BIP 70, 71, 72

One topic of discussion was the potential for a Man-in-the-Middle (MITM) attack on the HTTPS protocol, which could exploit flaws in the SSL PKI infrastructure and harm Bitcoin. It was suggested that implementing a payment protocol using the SSL PKI infrastructure could help identify weaknesses and motivate improvements.The possibility of MITM attacks in the context of Bitcoin URIs was also raised, with some companies using data loss prevention products with MITM capability. While the incentive for governments or large corporations to carry out such attacks may be low, detecting transactions could be more useful than meddling with them. Difficulties in using QR codes, especially under low light conditions, were also discussed, prompting suggestions for alternative approaches such as short URLs.The conversation touched on the security risks related to certificate authorities and MITM attacks, with HTTPS being seen as protective against certain attacks but not those involving scanning QR codes in person. The need for trust in HTTPS was debated, with one developer arguing that seeing a partner in person should eliminate the need for a certificate. However, concerns about the subversion of certificate authorities and the potential theft of funds due to broken certificates were also raised.Developers explored ways to make QR codes more scannable and reduce their size. Suggestions included changing parameters and exploring the use of BIP70 once available. The importance of HTTPS and the potential benefits of using the payments protocol were emphasized.The flexibility of the BIP72 specification was updated to allow for more options in processing transactions. Existing point-of-sale systems were identified as potential beneficiaries of the payments protocol, although concerns were raised about compatibility issues. The debate over Bitcoin URIs and the potential advantages of payment URIs was discussed, with considerations for proper payment infrastructure and the inclusion of 'SHOULDs' and 'MAYs' instead of 'MUSTs' in the specification.Additional discussions centered on wallet functionality, including concerns about wallets without P2P protocol support and the handling of locked inputs. The responsibility of confirming transactions and preventing their announcement to the network was also debated.Overall, these discussions demonstrate the ongoing development and considerations within the Bitcoin community regarding payment protocols, wallet functionality, and the use of URIs for transactions. Various suggestions were made to enhance security, improve scannability, and ensure backward compatibility.