Old Iron Earns More: A Technical Look at RustChain Proof-of-Antiquity

The blockchain project RustChain introduces a new consensus mechanism called Proof-of-Antiquity (PoA). Unlike traditional Proof-of-Work or Proof-of-Stake, PoA rewards the hardware used to mine rather than the computational power. The key principle is that older, rarer hardware is more valuable to the network. The project's documentation outlines multiplier tiers based on the age of the CPU, with older machines receiving higher rewards.

For example, a CPU from before 1985 multiplies rewards by 3.5x-4.0x, whereas modern CPUs multiply rewards by 0.8x-1.0x.

To prevent malicious actors from manipulating the system, RustChain incorporates six hardware fingerprinting checks that are difficult to spoof. These checks include measuring oscillator drift, cache timing, SIMD identity, thermal entropy, instruction jitter, and an anti-emulation defense. The fingerprinting process is designed to ensure that a machine's hardware identity is legitimate and not artificially created.

The system also includes a replay attack defense mechanism to prevent someone from capturing a real machine's fingerprint and replaying it later. This defense checks for exact duplicates, fresh measurements, and modified replays. Additionally, RustChain applies a time decay formula to reward earlier adopters. Older hardware earns a larger multiplier, while modern hardware earns bonuses based on its uptime.

The CPU detection mechanism in RustChain is a comprehensive regex-based system that identifies CPUs based on the /proc/cpuinfo brand string. The detection covers a wide range of CPU architectures, including Intel, AMD, PowerPC, Apple Silicon, RISC-V, Sun SPARC, SGI MIPS, Motorola 68K, Hitachi SuperH, and even game console CPUs. While regex-based CPU identification is inherently fragile and can be challenging, RustChain's approach is thorough and ensures that the right hardware is rewarded.