The Blockchain Specification
The blockchain specification, or chainspec, is a collection of configuration settings describing the network state at genesis and upgrades to basic system functionality (including system contracts and gas costs) occurring after genesis. This page describes each field in the chainspec, based on version 1.5.2 of the Casper node. The chainspec can and should be customized for private networks. The chainspec attributes are divided into categories based on what they are configuring.
protocol
These settings describe the active protocol version.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| version | The Casper node protocol version. | '1.5.2' |
| hard_reset | When set to true, clear blocks and transactions back to the switch block (the end of the last era) just before the activation point. Used during the upgrade process to reset the network progress. In most cases, this setting should be true. | true |
| activation_point | The protocol version that should become active. If it is a timestamp string, it represents the timestamp for the genesis block. This is the beginning of Era 0. By this time, a sufficient majority (> 50% + F/2 — see the finality_threshold_fraction below) of validator nodes must be running to start the blockchain. This timestamp is also used in seeding the pseudo-random number generator used in the contract runtime for computing the genesis post-state hash. If it is an integer, it represents an era ID, meaning the protocol version becomes active at the start of this era. | 9100 |
network
The following settings configure the networking layer.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| name | Human readable network name for convenience. The state_root_hash of the genesis block is the true identifier. The name influences the genesis hash by contributing to seeding the pseudo-random number generator used in the contract runtime for computing the genesis post-state hash. | 'casper' |
| maximum_net_message_size | The maximum size of an acceptable networking message in bytes. Any message larger than this will be rejected at the networking level. | 25_165_824 |
core
These settings manage the core protocol behavior.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| era_duration | Era duration. | '120min' |
| minimum_era_height | Minimum number of blocks per era. An era will take longer than era_duration if that is necessary to reach the minimum height. | 20 |
| minimum_block_time | Minimum difference between a block's and its child's timestamp. | '16384ms' |
| validator_slots | Number of slots available in the validator auction. | 100 |
| finality_threshold_fraction | A number between 0 and 1 representing the fault tolerance threshold as a fraction used by the internal finalizer. It is the fraction of validators that would need to equivocate to make two honest nodes see two conflicting blocks as finalized. Let's say this value is F. A higher value F makes it safer to rely on finalized blocks. It also makes it more difficult to finalize blocks, however, and requires strictly more than (F + 1)/2 validators to be working correctly. | [1, 3] |
| start_protocol_version_with_strict _finality_signatures_required | Protocol version from which nodes are required to hold strict finality signatures. | '1.5.0' |
| legacy_required_finality | The finality required for legacy blocks. Options are 'Strict', 'Weak', and 'Any'. Used to determine finality sufficiency for new joiners syncing blocks created in a protocol version before the start protocol version with strict finality signatures. | 'Strict' |
| auction_delay | Number of eras before an auction defines the set of validators. If a validator bonds with a sufficient bid in era N, it will be a validator in era N + auction_delay + 1. | 1 |
| locked_funds_period | The period after genesis during which a genesis validator's bid is locked. | '90days' |
| vesting_schedule_period | The period in which the genesis validator's bid is released over time after it is unlocked. | '13 weeks' |
| unbonding_delay | Default number of eras that need to pass to be able to withdraw unbonded funds. | 7 |
| round_seigniorage_rate | Round seigniorage rate represented as a fraction of the total supply. - Annual issuance: 8%. - Minimum block time: 2^15 milliseconds. - Ticks per year: 31536000000. (1+0.08)^((2^15)/31536000000)-1 is expressed as a fractional number below in Python: Fraction((1 + 0.08)**((2**15)/31536000000) - 1).limit_denominator(1000000000) | [7, 87535408] |
| max_associated_keys | Maximum number of associated keys for a single account. | 100 |
| max_runtime_call_stack_height | Maximum height of the contract runtime call stack. | 12 |
| minimum_delegation_amount | Minimum allowed delegation amount in motes. | 500_000_000_000 |
| prune_batch_size | Global state prune batch size for tip pruning in version 1.4.15. Possible values: - 0 when the feature is OFF - Integer if the feature is ON, representing the number of eras to process per block. | 0 |
| strict_argument_checking | Enables strict arguments checking when calling a contract; i.e., all non-optional args are provided and they are of the correct CLType. | false |
| simultaneous_peer_requests | Number of simultaneous peer requests. | 5 |
| consensus_protocol | The consensus protocol to use. Options are 'Zug' or 'Highway'. | 'Zug' |
| max_delegators_per_validator | The maximum amount of delegators per validator. If the value is 0, there is no maximum capacity. | 1200 |
| finders_fee | The split in finality signature rewards between block producer and participating signers. | [1, 5] |
| finality_signature_proportion | The proportion of baseline rewards going to reward finality signatures specifically. | [1, 2] |
| signature_rewards_max_delay | Lookback interval indicating how many past blocks we are looking at to reward. | 3 |
highway
These settings configure the Highway Consensus protocol.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| maximum_round_length | Highway dynamically chooses its round length between minimum_block_time and maximum_round_length. | '132seconds' |
| reduced_reward_multiplier | The factor by which rewards for a round are multiplied if the greatest summit has ≤50% quorum, i.e., no finality. Expressed as a fraction (1/5 by default on Mainnet). | [1, 5] |
transactions
These settings manage transactions and their lifecycle.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| max_payment_cost | The maximum number of motes allowed to be spent during payment. 0 means unlimited. | '0' |
| max_ttl | The duration after the transaction timestamp during which the transaction can be included in a block. | '18hours' |
| max_dependencies | The maximum number of other transactions a transaction can depend on (requiring them to have been executed before it can execute). | 10 |
| max_block_size | Maximum block size in bytes, including transactions contained by the block. 0 means unlimited. | 10_485_760 |
| max_transaction_size | Maximum transaction size in bytes. Size is of the transaction when serialized via ToBytes. | 1_048_576 |
| block_max_mint_count | Maximum number of mint transactions (i.e. transfers) allowed in a block. | 500 |
| block_max_auction_count | Maximum number of auction transactions allowed in a block. | 100 |
| block_max_install_upgrade_count | Maximum number of installer/upgrader transactions allowed in a block. | 2 |
| block_max_standard_count | Maximum number of other transactions (non-transfer, non-staking, non-installer/upgrader) allowed in a block. | 50 |
| block_max_approval_count | The maximum number of approvals permitted in a single block. | 2600 |
| block_gas_limit | The upper limit of the total gas of all transactions in a block. | 4_000_000_000_000 |
| payment_args_max_length | The limit of length of serialized payment code arguments. | 1024 |
| session_args_max_length | The limit of length of serialized session code arguments. | 1024 |
| native_transfer_minimum_motes | The minimum amount in motes for a valid native transfer. | 2_500_000_000 |
wasm
The following are Wasm-related settings.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| max_memory | Amount of free memory (in 64 kB pages) each contract can use for its stack. | 64 |
| max_stack_height | Max stack height (native WebAssembly stack limiter). | 500 |
wasm.storage_costs
These settings manage Wasm storage costs.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| gas_per_byte | Gas charged per byte stored in global state. | 630_000 |
wasm.opcode_costs
The following settings manage the cost table for Wasm opcodes.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| bit | Bit operations multiplier. | 300 |
| add | Arithmetic add operations multiplier. | 210 |
| mul | Mul operations multiplier. | 240 |
| div | Div operations multiplier. | 320 |
| load | Memory load operation multiplier. | 2_500 |
| store | Memory store operation multiplier. | 4_700 |
| const | Const store operation multiplier. | 110 |
| local | Local operations multiplier. | 390 |
| global | Global operations multiplier. | 390 |
| integer_comparison | Integer operations multiplier. | 250 |
| conversion | Conversion operations multiplier. | 420 |
| unreachable | Unreachable operation multiplier. | 270 |
| nop | Nop operation multiplier. | 200 |
| current_memory | Get the current memory operation multiplier. | 290 |
| grow_memory | Grow memory cost per page (64 kB). | 240_000 |
wasm.opcode_costs.control_flow
These settings manage costs for control flow operations.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| block | Cost for block opcode. | 440 |
| loop | Cost for loop opcode. | 440 |
| if | Cost for if opcode. | 440 |
| else | Cost for else opcode. | 440 |
| end | Cost for end opcode. | 440 |
| br | Cost for br opcode. | 35_000 |
| br_if | Cost for br_if opcode. | 35_000 |
| return | Cost for return opcode. | 440 |
| select | Cost for select opcode. | 440 |
| call | Cost for call opcode. | 68_000 |
| call_indirect | Cost for call_indirect opcode. | 68_000 |
| drop | Cost for drop opcode. | 440 |
wasm.opcode_costs.control_flow.br_table
The following settings manage br_table Wasm opcodes.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| cost | Fixed cost per br_table opcode. | 35_000 |
| size_multiplier | Size of target labels in the br_table opcode will be multiplied by size_multiplier. | 100 |
wasm.messages_limits
The following chainspec settings manage the cost of contract-level messages.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| max_topic_name_size | Maximum size of the topic name. | 256 |
| max_topics_per_contract | Maximum number of topics that can be added for each contract. | 128 |
| max_message_size | Maximum size in bytes of the serialized message payload. | 1_024 |
wasm.host_function_costs
The following settings specify costs for low-level bindings for host-side ("external") functions. More documentation and host function declarations are located in smart_contracts/contract/src/ext_ffi.rs.
- add = { cost = 5_800, arguments = [0, 0, 0, 0] }
- add_associated_key = { cost = 9_000, arguments = [0, 0, 0] }
- add_contract_version = { cost = 200, arguments = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0] }
- blake2b = { cost = 200, arguments = [0, 0, 0, 0] }
- call_contract = { cost = 4_500, arguments = [0, 0, 0, 0, 0, 420, 0] }
- call_versioned_contract = { cost = 4_500, arguments = [0, 0, 0, 0, 0, 0, 0, 420, 0] }
- cost_increase_per_message = 50
- create_contract_package_at_hash = { cost = 200, arguments = [0, 0] }
- create_contract_user_group = { cost = 200, arguments = [0, 0, 0, 0, 0, 0, 0, 0] }
- create_purse = { cost = 2_500_000_000, arguments = [0, 0] }
- disable_contract_version = { cost = 200, arguments = [0, 0, 0, 0] }
- emit_message = { cost = 200, arguments = [0, 0, 0, 0] }
- get_balance = { cost = 3_800, arguments = [0, 0, 0] }
- get_blocktime = { cost = 330, arguments = [0] }
- get_caller = { cost = 380, arguments = [0] }
- get_key = { cost = 2_000, arguments = [0, 440, 0, 0, 0] }
- get_main_purse = { cost = 1_300, arguments = [0] }
- get_named_arg = { cost = 200, arguments = [0, 0, 0, 0] }
- get_named_arg_size = { cost = 200, arguments = [0, 0, 0] }
- get_phase = { cost = 710, arguments = [0] }
- get_system_contract = { cost = 1_100, arguments = [0, 0, 0] }
- has_key = { cost = 1_500, arguments = [0, 840] }
- is_valid_uref = { cost = 760, arguments = [0, 0] }
- load_named_keys = { cost = 42_000, arguments = [0, 0] }
- manage_message_topic = { cost = 200, arguments = [0, 0, 0, 0] }
- new_uref = { cost = 17_000, arguments = [0, 0, 590] }
- random_bytes = { cost = 200, arguments = [0, 0] }
- print = { cost = 20_000, arguments = [0, 4_600] }
- provision_contract_user_group_uref = { cost = 200, arguments = [0, 0, 0, 0, 0] }
- put_key = { cost = 38_000, arguments = [0, 1_100, 0, 0] }
- read_host_buffer = { cost = 3_500, arguments = [0, 310, 0] }
- read_value = { cost = 6_000, arguments = [0, 0, 0] }
- read_value_local = { cost = 5_500, arguments = [0, 590, 0] }
- remove_associated_key = { cost = 4_200, arguments = [0, 0] }
- remove_contract_user_group = { cost = 200, arguments = [0, 0, 0, 0] }
- remove_contract_user_group_urefs = { cost = 200, arguments = [0, 0, 0, 0, 0, 0] }
- remove_key = { cost = 61_000, arguments = [0, 3_200] }
- ret = { cost = 23_000, arguments = [0, 420_000] }
- revert = { cost = 500, arguments = [0] }
- set_action_threshold = { cost = 74_000, arguments = [0, 0] }
- transfer_from_purse_to_account = { cost = 2_500_000_000, arguments = [0, 0, 0, 0, 0, 0, 0, 0, 0] }
- transfer_from_purse_to_purse = { cost = 82_000, arguments = [0, 0, 0, 0, 0, 0, 0, 0] }
- transfer_to_account = { cost = 2_500_000_000, arguments = [0, 0, 0, 0, 0, 0, 0] }
- update_associated_key = { cost = 4_200, arguments = [0, 0, 0] }
- write = { cost = 14_000, arguments = [0, 0, 0, 980] }
- write_local = { cost = 9_500, arguments = [0, 1_800, 0, 520] }
system_costs
The following settings manage protocol operating costs.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| wasmless_transfer_cost | Default gas cost for a wasmless transfer. | 100_000_000 |
system_costs.auction_costs
These settings manage the costs of calling the auction system contract entrypoints.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| get_era_validators | Cost of calling the get_era_validators entrypoint. | 10_000 |
| read_seigniorage_recipients | Cost of calling the read_seigniorage_recipients entrypoint. | 10_000 |
| add_bid | Cost of calling the add_bid entrypoint. | 2_500_000_000 |
| withdraw_bid | Cost of calling the withdraw_bid entrypoint. | 2_500_000_000 |
| delegate | Cost of calling the delegate entrypoint. | 2_500_000_000 |
| undelegate | Cost of calling the undelegate entrypoint. | 2_500_000_000 |
| run_auction | Cost of calling the run_auction entrypoint. | 10_000 |
| slash | Cost of calling the slash entrypoint. | 10_000 |
| distribute | Cost of calling the distribute entrypoint. | 10_000 |
| withdraw_delegator_reward | Cost of calling the withdraw_delegator_reward entrypoint. | 10_000 |
| withdraw_validator_reward | Cost of calling the withdraw_validator_reward entrypoint. | 10_000 |
| read_era_id | Cost of calling the read_era_id entrypoint. | 10_000 |
| activate_bid | Cost of calling the activate_bid entrypoint. | 10_000 |
| redelegate | Cost of calling the redelegate entrypoint. | 2_500_000_000 |
system_costs.mint_costs
These settings manage the costs of calling the mint system contract entrypoints.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| mint | Cost of calling the mint entrypoint. | 2_500_000_000 |
| reduce_total_supply | Cost of calling the reduce_total_supply entrypoint. | 10_000 |
| create | Cost of calling the create entrypoint. | 2_500_000_000 |
| balance | Cost of calling the balance entrypoint. | 10_000 |
| transfer | Cost of calling the transfer entrypoint. | 10_000 |
| read_base_round_reward | Cost of calling the read_base_round_reward entrypoint. | 10_000 |
| mint_into_existing_purse | Cost of calling the mint_into_existing_purse entrypoint. | 2_500_000_000 |
system_costs.handle_payment_costs
These settings manage the costs of calling entrypoints on the handle_payment system contract.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| get_payment_purse | Cost of calling the get_payment_purse entrypoint. | 10_000 |
| set_refund_purse | Cost of calling the set_refund_purse entrypoint. | 10_000 |
| get_refund_purse | Cost of calling the get_refund_purse entrypoint. | 10_000 |
| finalize_payment | Cost of calling the finalize_payment entrypoint. | 10_000 |
system_costs.standard_payment_costs
These settings manage the costs of calling entrypoints on the standard_payment system contract.
| Attribute | Description | Mainnet Setting |
|---|---|---|
| pay | Cost of calling the pay entrypoint and sending an amount to a payment purse. | 10_000 |