Module zebra_chain::work::difficulty

Block difficulty data structures and calculations

The block difficulty “target threshold” is stored in the block header as a 32-bit CompactDifficulty. The block::Hash must be less than or equal to the ExpandedDifficulty threshold, when represented as a 256-bit integer in little-endian order.

The target threshold is also used to calculate the Work for each block. The block work is used to find the chain with the greatest total work. Each block’s work value depends on the fixed threshold in the block header, not the actual work represented by the block header hash.

Modules

• arbitrary 🔒

Structs

• CompactDifficulty
  A 32-bit “compact bits” value, which represents the difficulty threshold for a block header.
• ExpandedDifficulty
  A 256-bit unsigned “expanded difficulty” value.
• PartialCumulativeWork
  Partial work used to track relative work in non-finalized chains
• U256
  Little-endian large integer type
• Work
  A 128-bit unsigned “Work” value.

Constants

• INVALID_COMPACT_DIFFICULTY
  An invalid CompactDifficulty value, for testing.

Traits

• ParameterDifficulty
  Network methods related to Difficulty