Enabling safe, compliant, and verifiable agent autonomy in environments where correctness is non-negotiable.

Aegis Protocol (aegis-protocol) is a high-performance C++ security framework for establishing cryptographic identity, trust, and accountability in autonomous AI agent ecosystems.

By combining Semantic Passports, a zero-trust communication model, and a semantically-aware policy engine, Aegis Protocol ensures that autonomous systems:

• operate within strictly defined safety and authorization boundaries
• produce verifiable, deterministic decisions
• maintain a tamper-evident audit trail of all actions

The system is implemented as composable C++ modules with a companion Python SDK, covering the full agent security lifecycle:

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🧩 Architecture Overview

Identity Layer

• PassportRegistry
• KeyRotation
• RevocationList
• MultiPartyIssuer

Communication Layer

• HandshakeValidator
• TransportIdentity
• NonceCache

Intelligence Layer

• SemanticClassifier
• PolicyEngine
• BFTConsensusEngine

Operational Layer

• Session State Machine
• ColdAuditVault
• TransparencyLog
• IncidentManager

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⏱ Trusted Time Model

All time-dependent authorization decisions are bound to a trusted, injected IClock abstraction.

• Prevents timestamp injection attacks
• Eliminates reliance on caller-controlled time
• Ensures consistent, verifiable authorization windows

Caller-supplied timestamps are accepted only for audit metadata, never for enforcement.

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🔐 Core Capabilities

Semantic Identity

Implements Semantic Passports (v1.0) — cryptographically signed identity credentials containing:

• model_id, version
• TTL (time-bounded validity)
• policy_hash
• Capability bitmap:
  • classifier_authority
  • classifier_sensitivity
  • bft_consensus
  • entropy_flush

All passports are signed via HMAC-SHA256, enforcing least-privilege at the identity layer.

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Zero-Trust Handshaking

A hardened three-message handshake providing:

• Ephemeral Diffie-Hellman forward secrecy
• Replay protection via partitioned nonce caches
• Transport identity binding (TLS fingerprint / address)
• Directional session key separation

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Context-Aware Policy Engine

Evaluates actions in real time using:

• Semantic Score: Authority (−1.0 → +1.0) vs Sensitivity (0.0 → 1.0)
• Configurable confidence thresholds
• Scope-aware policy enforcement

Outputs deterministic decisions:

• ALLOW
• FLAG
• DENY (fail-closed by default)

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Collective Resilience (BFT)

A Byzantine Fault Tolerant consensus layer:

• Uses geometric median aggregation (Weiszfeld method)
• Tolerates up to f = floor((n-1)/3) compromised agents
• Prevents adversarial manipulation of group decisions

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Behavioral Anomaly Detection

Session lifecycle: INIT → ACTIVE → SUSPECT → QUARANTINE → FLUSHING → RESYNC → CLOSED

• Tracks anomaly accumulation via a warp score
• Triggers entropy flush callbacks on threshold breach
• Provides structured incident context (session_id, incident_id, payload hashes)

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Tamper-Evident Accountability

• ColdAuditVault: hash-chained audit ledger
• TransparencyLog: append-only governance log

All events are:

• cryptographically linked
• verifiable via verify_chain()
• resistant to tampering

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Full Credential Lifecycle

Key and identity lifecycle: ACTIVE → ROTATING → RETIRED → PURGED

Features:

• Version-scoped revocation
• TTL-bound credentials
• N-of-M quorum issuance for high-value identities

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🚀 Intended Use

Aegis Protocol is designed for:

• Multi-agent AI systems
• Autonomous orchestration platforms
• Safety-critical AI deployments
• Regulated or compliance-heavy environments

It acts as a security enforcement layer between:

model inference → real-world action

It is designed to integrate beneath existing frameworks such as:

• LangChain
• AutoGen
• OpenAI Agents SDK

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🛠 Build Instructions

Clean build (recommended)

rm -rf build mkdir build && cd build cmake .. make -j8

Minimal standalone compile (reference entry point)

g++ -std=c++17 -O2 src/main_aegis_protocol.cpp -lssl -lcrypto -o aegis_daemon

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📏 Standards Alignment

Aegis Protocol aligns with:

NIST AI RMF 1.0 (MEASURE / GOVERN) NIST SP 800-53 Rev. 5 (IA / AC / AU / IR / SC) NIST SP 800-218A (Secure Software Development) DoD Zero Trust Architecture v2.0 OWASP LLM Top 10 (2025) ISA/IEC 62443-3-3 NERC CIP-007 / CIP-010

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📜 License

Licensed under the Apache License, Version 2.0.

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⚠️ Status

v1.0.0 — Initial Release

This release establishes:

Semantic Passport identity model Policy enforcement framework Audit and transparency infrastructure

Future versions will expand:

interoperability SDK coverage production integrations