Security Model

This document explains the security model and verification architecture used in Project Eidolon.

Multi-Signer Trust Model

Eidolon implements a distributed trust model that allows modules to be signed and verified by multiple trusted entities, rather than relying on a single central authority.

Key Concepts

• Trusted Signers: Public keys from entities you trust to sign modules
• Module Signatures: Detached cryptographic signatures (module.sig files)
• Verification Status: Levels including Verified, Signed-Untrusted, Unsigned, or Invalid

Trust Architecture

Unlike the traditional central verification model, Eidolon uses a web of trust approach:

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│  Module Author  │     │  Module Author  │     │  Module Author  │
│   (Trusted)     │     │  (Untrusted)    │     │   (Trusted)     │
└────────┬────────┘     └────────┬────────┘     └────────┬────────┘
         │                       │                       │
         ▼                       ▼                       ▼
┌────────────────┐      ┌────────────────┐      ┌────────────────┐
│ Signed Module  │      │ Signed Module  │      │ Signed Module  │
└────────┬───────┘      └────────┬───────┘      └────────┬───────┘
         │                       │                       │
         ▼                       ▼                       ▼
┌─────────────────────────────────────────────────────────────────┐
│                     Trusted Signers Registry                    │
│              (User's personal list of trusted keys)             │
└─────────────────────────────────────┬───────────────────────────┘
                                      │
                                      ▼
┌─────────────────────────────────────────────────────────────────┐
│                  Eidolon Security Verification                  │
└─────────────────────────────────────┬───────────────────────────┘
                                      │
                                      ▼
┌─────────────────────────────────────────────────────────────────┐
│                  Module Verification Decision                   │
│                                                                 │
│  ┌─────────────┐    ┌───────────────┐    ┌────────────────────┐ │
│  │   Verified  │    │    Signed     │    │      Unsigned      │ │
│  │ (Automatic  │    │  (Untrusted)  │    │ (Requires explicit │ │
│  │  approval)  │    │ (User prompt) │    │     approval)      │ │
│  └─────────────┘    └───────────────┘    └────────────────────┘ │
└─────────────────────────────────────────────────────────────────┘

Module Hash Generation

When a module is signed, the system computes a deterministic hash of its contents:

1. The entire module directory tree is scanned (excluding .sig files and cache files)
2. All files are hashed in a deterministic order
3. A combined SHA-256 hash is generated representing the entire module content

This hash ensures that any modification to the module's code will invalidate the signature.

Signature Verification

When Eidolon loads a module:

1. It checks for the presence of a module.sig file
2. It computes the module's hash using the same deterministic algorithm
3. It verifies the signature against the hash using trusted public keys
4. It determines the verification status:
5. Verified: Signature is valid and matches a trusted signer
6. Signed-Untrusted: Signature is valid but from an unknown signer
7. Unsigned: No signature file found
8. Invalid: Signature is invalid or corrupted

Security Modes

Eidolon supports three security modes:

1. Paranoid: Only verified modules from trusted signers are allowed
2. Default: Prompts for untrusted modules, allows verified modules automatically
3. Permissive: Allows all modules with appropriate warnings for unsigned ones

Command-Line Security Options

Security modes and behaviors can be configured via command-line flags:

eidolon run --security-mode=paranoid pipeline_name
eidolon run --allow-unverified pipeline_name

Signature File Format

A module signature is a detached binary file containing:

• The raw signature bytes produced by signing the module hash
• Using PSS padding and SHA-256 hashing algorithm

The signature file is named module.sig and is placed in the module's root directory.