Tsinghua University Tsinghua University Tsinghua University Tsinghua University Given that an AS collaboration scheme for inter-domain source address validation requires an information-sharing platform, this document proposes a new approach by leveraging Resource Public Key Infrastructure (RPKI) architecture to validate the authenticity of source address of packets. Source Origin Authorization (SOA) is a newly defined cryptographically signed object; it provides a means of recording information about the last Autonomous System (AS) traversed by packets before reaching a specific AS. When validated, the eContent of an SOA object confirms that the holder of the listed AS Number (ASN) has authorized the specified pre-ASes. This enables other ASes to collaboratively filter spoofed traffic, enhancing global Internet security by mitigating source address spoofing and DDoS attacks.