SEAL: Secure and Efficient Authentication using Linkage for Blockchain Networks

The cryptocurrency's permissionless and large-scale broadcasting requirements prohibit the traditional authentication implementation on the blockchain's underlying peer-to-peer (P2P) networking. Thus, blockchain networking implementations remain vulnerable to networking integrity threats such as spoofing or hijacking. We design Secure and Efficient Authentication using Linkage (SEAL) to build connection security for permissionless blockchain networking. SEAL uses the linkage between the pack-ets for a symmetric operation, in contrast to the traditional au-thentication approach relying on identity-credential-based trust. To make it appropriate for cryptocurrency networking, SEAL utilizes the packet header, protects the end-to-end connection, and separates the online process (based on a simple mixing operation) vs. the offline process (the in-advance construction of the pseudo-random number chain) so that the realtime overhead is minimal for greater efficiency and practicality. We implement SEAL on a working Bitcoin node and show that SEAL works and provides minimal overhead. Furthermore, we use a networking simulator to simulate the Bitcoin Mainnet and analyze the SEAL impact on the block propagation delay on the network, e.g., SEAL yields 2.04 times smaller delay and 1.25 times smaller delay in block propagation than HMAC and ChaCha20-Poly1305, respectively.