IPv4-64: Security and Performance Analysis: A technical comparison of IPv4-64 security mechanisms and forwarding performance against IPv4, IPv6, and prior address extension proposals

IPv4-64 is a network protocol that extends IPv4 addresses from 32 bits to 64 bits while keeping dotted-decimal notation, backward-compatible addressing, and fixed-header design. This document compares IPv4-64 against IPv4 (RFC 791), IPv6 (RFC 8200), QUIC (RFC 9000), and three prior IPv4 address extension proposals: IPv4+4 (Valkó/Turànyi, 2002), EnIP (draft-chimiak-enhanced-ipv4), and IPv10 (draft-omar-ipv10). The comparison covers six security areas — source spoofing, SYN flood defense, fragment injection, UDP amplification, scanner reconnaissance, and firewall evasion — and four performance areas: ASIC pipeline depth, per-hop processing cost, cache line utilization, and per-segment TCP overhead. IPv4-64 introduces six in-header security mechanisms (Source Validation Token, Fragment Token, Retry Cookie, Validated flag, CV flag, and strict silent drop) that interact to close the three largest classes of volumetric internet attack. The SVT key exchange operates through bilateral trust between peering operators without a central certificate authority, using the same physical trust relationships that already exist in network peering. No existing deployed protocol or prior proposal addresses source spoofing, SYN flooding, and UDP amplification simultaneously at the network and transport layer. IPv4-64 eliminates all variable-length parsing from the IP, TCP, and UDP headers. The IP header is fixed at 32 bytes, the TCP header at 24 bytes, and the UDP header at 10 bytes. Every field is at a known byte offset. This produces a constant ASIC pipeline depth where worst-case forwarding performance equals best-case forwarding performance — a property no existing protocol provides. The fixed layout eliminates header checksum recomputation (removed for the same reason IPv6 removed it), per-segment TCP option parsing on established connections, conditional cache line reads for variable-length headers, multiplexer logic for variable payload offsets, and parser state machines for option and extension header dispatch. A firewall extracts a 5-tuple from five fixed-offset reads with no computation, which maps directly to TCAM hardware without a pre-processing normalization stage. Parser differential attacks — where a firewall and destination disagree on field positions due to variable-length header interpretation — are structurally impossible because there is no parser. The combined IP and TCP header (56 bytes) fits in a single 64-byte CPU cache line with 8 bytes remaining for the start of application payload, reducing memory access cost to one cache line read for complete header processing at all layers.