1.7 A Comparative Anatomy of Hidden Networks (F2F, I2P, Tor, Yggdrasil, Nym, Lokinet)

Hidden networks — commonly called darknets — differ significantly in architecture, routing logic, threat models, and intended use cases.
While most people only know Tor, the darknet ecosystem is an entire family of anonymity-preserving overlay networks, each engineered to solve a different type of privacy problem.

This chapter examines six major systems:

• F2F Networks (Friend-to-Friend)

• I2P (Invisible Internet Project)

• Tor (The Onion Router)

• Yggdrasil

• Nym Mixnet

• Lokinet

This comparative anatomy highlights their design philosophies, routing mechanisms, security assumptions, and sociotechnical roles.

A. F2F Networks (Friend-to-Friend)

F2F networks are a category of peer-to-peer networks where only trusted peers connect directly.
Examples include: Retroshare, GNUnet in F2F mode, and earlier P2P prototypes.

Key Architectural Features

1. Private Peer Connections
   Users connect only to known contacts (friends).
   This reduces exposure but limits scalability.

2. Decentralization
   No central servers.
   Routing is done through trusted relationships.

3. High Resistance to Infiltration
   Hard for adversaries to enter without social engineering.

4. Low Anonymity Set
   The network size is limited to the number of trusted peers.

Use Case

Ideal for:

• activist groups

• private communities

• censorship-resistant messaging

Not suited for large-scale anonymous publishing.

B. I2P — Invisible Internet Project

I2P is a fully internal darknet designed so that all traffic stays inside the network.
Its architecture uses garlic routing, an evolved form of onion routing where multiple messages are bundled together to make traffic analysis harder.

Key Architectural Features

1. Unidirectional Tunnels
   Separate tunnels for inbound and outbound traffic.
   This reduces certain correlation attacks.

2. Garlic Routing
   Multiple messages packed into a “garlic bulb.”
   Harder to isolate individual packets.

3. Decentralized Routing
   No centralized directory authorities (unlike Tor).
   Routing uses a distributed netDB (network database).

4. Internal Services (Eepsites)
   I2P hosts its own websites ending in .i2p.

Use Case

• anonymous peer-to-peer applications

• chat, file-sharing

• decentralized communities

• internal anonymous services rather than clearnet access

C. Tor — The Onion Router

Tor is the most widely known anonymity network, using onion routing with multi-layer encryption through volunteer nodes.

Key Architectural Features

1. Onion Routing
   Data is wrapped in multiple encryption layers.
   Each relay peels one layer and sends the packet forward.

2. Directory Authorities
   Centralized but highly audited servers that maintain the relay list.
   Improve network reliability and consistency.

3. Hidden Services (.onion)
   Tor allows both client and server anonymity.

4. Large Anonymity Set
   Thousands of relays and millions of users.

Use Case

• anonymity for browsing

• hosting hidden services

• journalism and secure drops

• anti-censorship

Tor sacrifices some performance for usability and scale.

D. Yggdrasil — Encrypted Global Mesh Network

Yggdrasil is a newer experimental network that creates an end-to-end encrypted IPv6-only global mesh using a Distributed Hash Table (DHT) for routing.

Key Architectural Features

1. End-to-End Encryption by Default
   Every node has a cryptographic public key as its address.

2. Global IPv6 Network
   Each node receives an IPv6 address derived from its public key.

3. DHT-Based Routing
   Ensures efficient path finding and global connectivity.

4. No Onion Routing
   Yggdrasil is focused on secure routing, not strong anonymity.

Use Case

• decentralized infrastructure

• experimental networking

• global encrypted IPv6 overlay

Good for privacy, but not designed as a strong anonymity network.

E. Nym Mixnet — Next-Generation Metadata-Resistant Network

Nym revives and modernizes Chaumian mix networks, designed to eliminate metadata leakage — something onion routing struggles with under global adversaries.

Key Architectural Features

1. Mix Nodes
   Nodes batch, delay, and shuffle packets to break correlation.

2. Full Metadata Protection
   Prevents timing analysis, volume analysis, and global attacker correlation.

3. Sphinx Packet Format
   A modern, efficient, compact format for mix networks.

4. Incentivized Participation
   Nodes can be rewarded through blockchain mechanisms.

Use Case

• high-security communications

• whistleblowing

• resistant to nation-state surveillance

• privacy for messaging and credentials

Nym is considered stronger than Tor in metadata protection, but slower because of batching delays.

F. Lokinet (Oxen Network)

Lokinet is a privacy network based on the LLARP (Low Latency Anonymous Routing Protocol), aiming for faster anonymity than Tor.

Key Architectural Features

1. SNODEs (Service Nodes)
   Staked nodes that provide routing and anonymity.

2. High-speed Onion Routing Variant
   Lower latency compared to Tor.

3. Exit Functionality
   Allows anonymous access to the clearnet.

4. Onion Services Equivalent
   Called “Lokinet SNApps.”

Use Case

• real-time online applications needing privacy

• voice/video communication

• faster anonymous internet routing

Lokinet focuses on balancing anonymity with performance.

G. Comparative Architecture Analysis (Point-Wise)

1. Routing Approach

• Tor: onion routing

• I2P: garlic routing

• Nym: mixnet w/ batching

• Yggdrasil: DHT-based encrypted mesh

• Lokinet: LLARP (low-latency onion routing)

• F2F: direct trusted P2P connections

2. Anonymity Level

Highest: Nym
High: Tor, I2P
Moderate: Lokinet
Low/Variable: Yggdrasil
Social-layer anonymity: F2F networks

3. Performance

Fastest: Yggdrasil, Lokinet
Moderate: Tor
Variable: I2P
Slowest: Nym (because mixing requires delays)

4. Use Case Focus

• Tor: browser anonymity, hidden websites

• I2P: internal darknet communities

• Nym: metadata-resistant communications

• Yggdrasil: decentralized encrypted networking

• Lokinet: real-time anonymous routing

• F2F: private communities

H. Why Multiple Hidden Networks Exist

Each system solves a different privacy problem:

• Tor optimizes scale and usability

• Nym optimizes metadata protection

• I2P optimizes internal darknet resilience

• Lokinet optimizes speed

• Yggdrasil optimizes global encrypted addressing

• F2F optimizes trust boundaries

No single anonymity network can solve all privacy challenges simultaneously — hence the ecosystem diversity.