Decentralized Identity and the Prevention of Public Key Substitution Attacks

A Technical Survey of Key Event Infrastructure, Hardware Security, and Distributed Trust Models

Abstract

Public Key Infrastructure (PKI) authentication, despite its cryptographic rigor, is subject to a class of attacks that exploit not the mathematics of key generation but the integrity of the systems that bind identities to those keys. This paper examines the problem of public key substitution, wherein a malicious or compromised database administrator may silently replace a legitimate user's public key with one under adversarial control. It surveys the primary engineering defenses against this threat, including Hash-based Message Authentication Codes (HMACs), digital signing services, Hardware Security Modules (HSMs), and append-only audit logs. The analysis then proceeds to examine more fundamental architectural remedies, notably the Key Event Receipt Infrastructure (KERI) protocol, Soroban smart contracts on the Stellar blockchain, and deterministic key derivation from BIP-39 seed phrases. Hardware instantiation of these systems through PIV-compliant JavaCards is also addressed, culminating in a proposed layered identity model relevant to decentralized social networking applications such as Hyphero.