Abstract

In the zero-sum arena of Maximal Extractable Value (MEV) and high-frequency crypto trading, infrastructure latency is the primary determinant of alpha. While strategy logic (the “Brain”) has been commoditized, execution infrastructure (the “Body”) remains a critical differentiator. Institutional funds managing $50M-$500M typically rely on “robust” SaaS custody solutions that prioritize compliance over speed, introducing a structural latency disadvantage defined as the “Middle Latency Trap.”

This report analyzes the physics of latency in distributed systems, quantifies the “serialization tax” of standard APIs, and details the architecture of Pulusu—a proprietary signing stack leveraging AWS Nitro Enclaves and kernel-bypass networking to achieve <45µs execution times. We further introduce a methodology for “Trustless Verification” using non-root, user-space tooling to validate infrastructure performance without compromising security boundaries.

1. The Physics of Latency in Distributed Execution

The prevailing DevOps philosophy in crypto infrastructure focuses on “five nines” of availability. However, in the context of block auctions (Gas Wars, FIFO mempools), availability is insufficient; velocity is paramount.

1.1 The Speed of Light vs. The Speed of Serialization

In a vacuum, light travels at $c \approx 300,000$ km/s. In fiber optic cables, the refractive index ($n \approx 1.5$) reduces this to $\sim 200$ km/ms.

However, in modern colocated infrastructure (e.g., AWS us-east-1), physical distance is rarely the bottleneck. The bottleneck is computational overhead.

Standard institutional setups utilize a “Signing Loop” that incurs significant penalties:

1. Serialization: Converting binary transaction data to JSON strings for REST APIs costs CPU cycles.
2. Protocol Overhead: The TCP 3-way handshake and TLS negotiation introduce multiple Round-Trip Times (RTT) before data transfer begins.
3. Kernel Traversal: Moving data from User Space (Ring 3) to Kernel Space (Ring 0) for network transmission adds non-trivial jitter.

The “SaaS Penalty”:

In a block time of 400ms (Solana), a 200ms delay effectively removes the fund from 50% of competitive auctions.

2. The Market Failure: The “Middle Latency Trap”

The current market offers a polarized choice for crypto funds [1]:

• Retail/Cold Storage (Ledger/Metamask): High security, extreme latency (>30s). Unusable for algorithmic trading.
• Institutional SaaS (Fireblocks): SOC-2 compliant and secure, but architecturally limited by API latency and public internet routing.
• True HFT (Proprietary): Sub-microsecond execution using bare-metal servers and FPGAs. Requires a dedicated engineering team ($500k+/yr).

The Trap: Funds with $50M-$500M AUM are caught in the middle. They require HFT speeds to compete on DEXs like Arbitrum and Solana but lack the resources to build proprietary bare-metal stacks. They default to SaaS providers, effectively paying a “Latency Tax” on every trade.

3. Pulusu Architecture: The “Day 1” HFT Stack

Pulusu resolves this paradox by shifting the paradigm from Custody-as-a-Service to Infrastructure-as-Code (IaC). The architecture moves the signing environment to the transaction source, rather than shipping the transaction to a remote signer [2].

3.1 The Secure Enclave (Compute Isolation)

The core of the Pulusu stack is the AWS Nitro Enclave, a Trusted Execution Environment (TEE) isolated from the parent EC2 instance [3].

• Attack Surface Reduction: Nitro Enclaves have no persistent storage, no interactive access (SSH), and no external networking. Even a root user on the parent instance cannot access the Enclave’s memory.
• Memory-Resident Keys: Private keys are decrypted via AWS KMS only within the Enclave’s volatile memory space.

3.2 VSOCK: Eliminating the Network Stack

Instead of REST APIs over TCP/IP, Pulusu utilizes VSOCK (Virtual Sockets).

• Mechanism: VSOCK enables communication between the Trading Bot (Parent) and the Signer (Enclave) via a secure logical channel that bypasses the host’s physical Network Interface Card (NIC).
• Result: Zero-network-hop communication. Data transfer mimics a memory copy rather than a network transmission.

3.3 The Pulusu Router (Rust & Kernel Bypass)

The interface to the Enclave is handled by the Pulusu Router, written in Rust to ensure memory safety without garbage collection pauses [2].

• Kernel Bypass: We utilize DPDK-style optimizations to process requests in user space, avoiding expensive context switches.
• CPU Pinning (isolcpus): Specific vCPUs are dedicated solely to the signing thread. This prevents the Linux scheduler from preempting the process, eliminating “jitter” caused by noisy neighbors [4].

4. Antifragile Broadcasting: Solving the Reorg Problem

Speed is irrelevant if the transaction executes on a stale block. Pulusu implements an Antifragile Broadcaster to mitigate chain reorganization risks [2].

4.1 Reorg Detection Logic

The Router subscribes to the NewHead event stream directly from the execution client.

• Event: A new block header arrives.
• Check: Does the ParentHash match our internal state?
• Reaction: If a mismatch is detected (Reorg), the Router invalidates the pending nonce and triggers a re-sign event in <50µs.

This allows the bot to “front-run” the reorg realization of slower competitors who rely on standard database rollbacks.

5. Trustless Verification: The “Canary” Methodology

A major barrier to upgrading infrastructure is the opacity of “Managed Services.” Funds often assume their cloud instances are optimized. To validate the need for Pulusu without violating strict “No Root” security policies, we employ a “Trustless Verification” methodology [5].

5.1 Latency-Audit (Static Analysis)

A CLI tool that scans /proc and /sys to detect configuration drift against HFT standards:

• Transparent Hugepages (THP): Checks if THP is enabled (often default), which causes memory compaction stalls (+50µs).
• NUMA Misalignment: Verifies if the trading process and NIC are on the same memory node to avoid the QPI interconnect tax (+600ns).

5.2 Latencyscope (Dynamic Analysis)

A user-space “Canary” that runs a tight execution loop to measure Involuntary Context Switches.

• Method: It measures the variance (jitter) of its own execution loop.
• Insight: If latencyscope detects a 2ms stall, it statistically proves the trading bot is also suffering 2ms stalls due to OS background tasks.

6. Conclusion

The era of “General Purpose” infrastructure for crypto funds is ending. As markets mature, infrastructure is the alpha. Pulusu provides the “Day 1” HFT stack—democratizing access to sub-millisecond execution while maintaining the SOC-2 compliance required by auditors. It is not merely a tool; it is the baseline requirement for solvency in the modern algorithmic trading landscape.