net.i2p.data

Class RoutingKeyGenerator

java.lang.Object

net.i2p.data.RoutingKeyGenerator

Direct Known Subclasses:

RouterKeyGenerator

public abstract class RoutingKeyGenerator
extends Object

Interface for transforming hashes into routing keys for I2P network database operations.

RoutingKeyGenerator provides hash transformation for distributed hash table routing:

• Hash Transformation: Consistent munging of hashes into routing keys
• Mod Data: Transformation parameters updated periodically
• DHT Routing: Enables efficient key-based lookup in network database
• Load Distribution: Spreads storage and lookup load across key space

Key Operations:

• getRoutingKey(Hash) - Transform hash to routing key
• getLastChanged() - Get current mod data version
• getInstance() - Get generator for current context

Transformation Process:

• Consistent Algorithm: Same transformation applied to all hashes
• Mod Data Input: Current network parameters affect transformation
• Deterministic: Same hash always produces same routing key
• Reversible: Process can be inverted for analysis

Context Availability:

• Router Context: Available only in RouterContext, not I2PAppContext
• Implementation: Concrete implementation in RouterKeyGenerator
• Client Limitation: Not available for client-only operations

Evolution:

• Pre-0.9.16: Full implementation with transformation logic
• Post-0.9.16: Interface with router-specific implementation
• Separation: Core interface in data package, implementation in router

Usage in I2P:

• NetDb Storage: Keys determine database storage location
• Floodfill Operations: Routing keys used for network distribution
• Lookup Efficiency: Fast key-based data retrieval
• Load Balancing: Distributes network load across key space

Security Considerations:

• Key Distribution: Prevents targeted attacks on specific keys
• Load Balancing: Avoids hotspots in network database
• Sybil Resistance: Makes targeted attacks more difficult
• Mod Data Rotation: Periodic changes prevent long-term attacks

Performance Aspects:

• Efficient Lookup: O(1) key-based database access
• Uniform Distribution: Spreads load across all network nodes
• Cache Optimization: Hot routing keys cached for fast access
• Minimal Computation: Fast transformation algorithm

Constructor Summary

Constructors

Constructor and Description
RoutingKeyGenerator()

Method Summary

Modifier and Type	Method and Description
static RoutingKeyGenerator	getInstance() Get the generator for this context.
abstract long	getLastChanged() The version of the current (today's) mod data.
abstract Hash	getRoutingKey(Hash origKey) Get the routing key for a key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RoutingKeyGenerator

public RoutingKeyGenerator()

Method Detail

getInstance

public static RoutingKeyGenerator getInstance()

Get the generator for this context.

Returns:

null in I2PAppContext; non-null in RouterContext.

getLastChanged

public abstract long getLastChanged()

The version of the current (today's) mod data. Use to determine if the routing key should be regenerated.

getRoutingKey

public abstract Hash getRoutingKey(Hash origKey)

Get the routing key for a key.

Throws:

IllegalArgumentException - if origKey is null