The block command handles block production and querying. It allows authorities to produce new blocks and anyone to browse the blockchain.
Subcommands
produce - Produce a new block (authority only)list - List recent blocksinfo - Show detailed block information
Produce Block Produce a new block containing pending transactions from the mempool.
minichain block produce --authority < NAM E >
Basic Usage cargo run --release -- block produce --authority authority_0
Output: Producing new block... Authority: 0xf4a5e8c2b9d7f3a1e6b8c4d9f2a5e8c1 Current Height: 0 ✓ Block produced Hash: 0x7d9f2a5c8e4b1f3a6c9e2d5f8a1c4e7b... Height: 1 Txs: 2
Authority Selection Keypair name of the authority (without .json extension).
Example: --authority authority_0 --authority authority_1
The authority must be registered during blockchain initialization.
Authority Validation Minichain uses Proof of Authority (PoA) consensus with round-robin scheduling:
authority_index = block_height % authority_count
Example with 3 authorities: Block Height Required Authority 0 authority_0 1 authority_1 2 authority_2 3 authority_0 4 authority_1
If the wrong authority tries to produce a block:
$ minichain block produce --authority authority_1 Error: Address 0x3d8e9f2a6b4c1e7f8a2c5d9e1f4b7a3c is not an authority. Authorities: [ "0xf4a5e8c2b9d7f3a1e6b8c4d9f2a5e8c1" , ...]
See the Consensus documentation for more details on PoA validation. Block Production Process When producing a block:
Fetch pending transactions from mempoolValidate authority - Verify correct authority for current heightExecute transactions - Run each transaction in the VMUpdate state - Apply state changes to account balances, nonces, storageCalculate state root - Generate merkle root of stateCreate block - Assemble header and transaction listSign block - Authority signs with Ed25519Store block - Persist to database
Empty Blocks You can produce blocks with no transactions:
minichain block produce --authority authority_0
Output: ✓ Block produced Hash: 0x7d9f2a5c8e4b1f3a6c9e2d5f8a1c4e7b... Height: 1 Txs: 0
Empty blocks advance the chain height and update the timestamp, but don’t modify account state.
List Blocks Display recent blocks in the chain.
minichain block list [OPTIONS]
Basic Usage cargo run --release -- block list
Output: Recent Blocks: #4 0x9f3a6c2e8d5b... (2 txs) #3 0x7d4b8f2a5c9e... (1 txs) #2 0x5c1e9f3a6d8b... (3 txs) #1 0x3a8d5f2c9e1b... (2 txs) #0 0x1f7c4e9a2d6b... (0 txs)
Options Count Number of blocks to display. Defaults to 10.
Example: minichain block list --count 20
Shows the most recent N blocks, in reverse chronological order (newest first).
Show detailed information about a specific block.
minichain block info < BLOCK_I D >
Query by Height cargo run --release -- block info 5
Output: Block Information: Height: 5 Hash: 0x7d9f2a5c8e4b1f3a6c9e2d5f8a1c4e7b... Parent Hash: 0x5c1e9f3a6d8b2f4a7c9e2d5f8a1c4e7b... State Root: 0x3a8d5f2c9e1b4f7a6c9e2d5f8a1c4e7b... Timestamp: 1709740123 Transactions: 2 Transactions: 1. 0x9f3a6c2e8d5b... 2. 0x7d4b8f2a5c9e...
Query by Hash minichain block info 0x7d9f2a5c8e4b1f3a6c9e2d5f8a1c4e7b...
Returns the same detailed output. The CLI automatically detects whether you provided a height (number) or hash (hex string).
Height: Block number (genesis = 0)Hash: Blake3 hash of the block headerParent Hash: Hash of the previous blockState Root: Merkle root of the account stateTimestamp: Unix timestamp when block was producedTransactions: Number of transactions in the block
Complete Workflow Here’s a typical block production workflow:
# 1. Initialize chain minichain init --authorities 1 # 2. Check initial state (genesis block only) minichain block list # Output: # Recent Blocks: # #0 0x1f7c4e9a2d6b... (0 txs) # 3. Create accounts and fund them minichain account new --name alice minichain account mint --from authority_0 --to < ALIC E > --amount 50000 # 4. Submit transactions minichain tx send --from alice --to < BO B > --amount 100 minichain tx send --from alice --to < CHARLI E > --amount 200 # 5. Produce block to execute transactions minichain block produce --authority authority_0 # Output: # ✓ Block produced # Height: 1 # Txs: 2 # 6. View updated chain minichain block list # Output: # Recent Blocks: # #1 0x7d9f2a5c8e4b... (2 txs) # #0 0x1f7c4e9a2d6b... (0 txs) # 7. Examine the new block minichain block info 1 # Output: # Height: 1 # Transactions: 2 # 1. 0x9f3a6c2e8d5b... # 2. 0x7d4b8f2a5c9e...
Multiple Authorities With multiple authorities, block production rotates:
# Initialize with 3 authorities minichain init --authorities 3 # Block 1: authority_1 must produce minichain block produce --authority authority_1 # Block 2: authority_2 must produce minichain block produce --authority authority_2 # Block 3: authority_0 must produce (wraps around) minichain block produce --authority authority_0 # Block 4: authority_1 again minichain block produce --authority authority_1
Trying to use the wrong authority fails:
# Current height is 1, so authority_1 should produce minichain block produce --authority authority_0 # Error: Wrong authority for height 1
Block Validation Each block is validated for:
Authority signature - Block signed by correct authority keypairAuthority schedule - Authority matches height % authority_countTimestamp - Not too far in future (allows small clock drift)Parent hash - Links to previous blockTransaction validity - All transactions pass validationState root - Matches computed state after execution
In a single-node setup, you’re unlikely to hit validation errors. These checks become critical in multi-node deployments.
Block Structure A block contains:
Block { header : BlockHeader { height : u64 , prev_hash : Hash , state_root : Hash , timestamp : u64 , authority : Address , }, transactions : Vec < Transaction >, signature : Signature , }
The block hash is computed from the header:
block_hash = blake3 ( header )
Common Errors Authority Not Found Error: Keypair file not found: data/keys/authority_0.json. Use 'minichain account new' to create one.
Solution: Ensure you ran minichain init to generate authority keypairs.Wrong Authority Error: Address 0x3d8e9f2a... is not an authority. Authorities: [ "0xf4a5e8c2..." , ...]
Solution: Use an authority address from the list in config.json.Chain Not Initialized Error: Failed to open storage. Did you run 'minichain init'?
Solution: Run minichain init first.Block Not Found Solution: Check the block height/hash is correct with minichain block list.Next Steps
Deploy Contracts Deploy smart contracts in blocks
Explore Chain Query blockchain state and history