Struct BlockHeader 

pub struct BlockHeader { /* private fields */ }

The header of a block. It contains metadata about the block, commitments to the current state of the chain and the hash of the proof that attests to the integrity of the chain.

A block header includes the following fields:

• version specifies the version of the block header itself. It changes when fields are added to or removed from the header, and when the scheme behind one of the header’s commitments changes, for example the structure of the SMTs or of the MMR.
• timestamp is the time when the block was created, in seconds since UNIX epoch. The u32 is sufficient to represent timestamps up to year 2106.
• block_num is a unique sequential number of the current block.
• prev_block_commitment is the hash of the previous block header.
• chain_commitment is a commitment to an MMR of the entire chain where each block is a leaf.
• account_root is a commitment to account database.
• nullifier_root is a commitment to the nullifier database.
• note_root is a commitment to all notes created in the current block.
• tx_commitment is a commitment to the set of transaction IDs which affected accounts in the block.
• validator_config is the set of validator public keys authorized to sign the next block, together with the quorum, see ValidatorConfig for more details.
• fee_parameters are the parameters defining the base fees, see FeeParameters for more details.
• protocol_config_commitment is the commitment to the chain’s ProtocolConfig.
• next_protocol_config is the scheduled protocol upgrade, if any, see NextProtocolConfig for more details.
• sub_commitment is a sequential hash of all fields except the note_root.
• commitment is a 2-to-1 hash of the sub_commitment and the note_root.

Implementations

impl BlockHeader

pub fn new( prev_block_commitment: Word, block_num: BlockNumber, chain_commitment: Word, account_root: Word, nullifier_root: Word, note_root: Word, tx_commitment: Word, validator_config: ValidatorConfig, fee_parameters: FeeParameters, protocol_config_commitment: Word, next_protocol_config: Option<NextProtocolConfig>, timestamp: u32, ) -> Self

Creates a new block header.

pub fn version(&self) -> u8

Returns the block version.

pub fn commitment(&self) -> Word

Returns the commitment of the block header.

pub fn sub_commitment(&self) -> Word

Returns the sub commitment of the block header.

The sub commitment is a sequential hash of all block header fields except the note root. This is used in the block commitment computation which is a 2-to-1 hash of the sub commitment and the note root [hash(sub_commitment, note_root)]. This procedure is used to make the note root easily accessible without having to unhash the entire header.

pub fn prev_block_commitment(&self) -> Word

Returns the commitment to the previous block header.

pub fn block_num(&self) -> BlockNumber

Returns the block number.

pub fn block_epoch(&self) -> u16

Returns the epoch to which this block belongs.

This is the block number shifted right by BlockNumber::EPOCH_LENGTH_EXPONENT.

pub fn chain_commitment(&self) -> Word

Returns the chain commitment.

pub fn account_root(&self) -> Word

Returns the account database root.

pub fn nullifier_root(&self) -> Word

Returns the nullifier database root.

pub fn note_root(&self) -> Word

Returns the note root.

pub fn validator_config(&self) -> &ValidatorConfig

Returns the validator configuration authorized to sign the next block.

A block’s signatures are verified against the validator_config committed to by its parent block, not against this field. See the BlockHeader docs for details.

pub fn tx_commitment(&self) -> Word

Returns the commitment to all transactions in this block.

The commitment is computed as sequential hash of (transaction_id, account_id) tuples. This makes it possible for the verifier to link transaction IDs to the accounts which they were executed against.

pub fn fee_parameters(&self) -> &FeeParameters

Returns a reference to the FeeParameters in this header.

pub fn protocol_config_commitment(&self) -> Word

Returns the commitment to the chain’s ProtocolConfig.

pub fn next_protocol_config(&self) -> Option<&NextProtocolConfig>

Returns the protocol upgrade scheduled by this block, if any.

pub fn next_protocol_config_commitment(&self) -> Word

Returns the commitment to the scheduled protocol upgrade, or Word::empty if no upgrade is scheduled.

pub fn timestamp(&self) -> u32

Returns the timestamp at which the block was created, in seconds since UNIX epoch.

pub fn epoch_block_num(&self) -> BlockNumber

Returns the block number of the epoch block to which this block belongs.

pub fn to_elements(&self) -> Vec<Felt>

Returns this header as a sequence of field elements.

The element layout is:

[
    [version, block_num, timestamp, 0],
    PREV_BLOCK_COMMITMENT,
    CHAIN_COMMITMENT,
    ACCOUNT_ROOT,
    NULLIFIER_ROOT,
    TX_COMMITMENT,
    PROTOCOL_CONFIG_COMMITMENT,
    VALIDATOR_CONFIG_COMMITMENT,
    NEXT_PROTOCOL_CONFIG_COMMITMENT,
    [verification_base_fee, 0, 0, 0],
    NOTE_ROOT,
]

This is the canonical encoding of a header. It is the layout of the kernel’s block data memory section and the order in which the header is provided to the kernel, so keep it in sync with the kernel’s process_block_data procedure.

Note that BlockHeader::commitment is not the sequential hash of these elements: the note root is hashed separately so that it stays accessible without unhashing the whole header. All elements but the trailing note root form the preimage of BlockHeader::sub_commitment.

Trait Implementations

impl Clone for BlockHeader

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BlockHeader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deserializable for BlockHeader

fn read_from<R: ByteReader>( source: &mut R, ) -> Result<Self, DeserializationError>

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn min_serialized_size() -> usize

Returns the minimum serialized size for one instance of this type.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

fn read_from_bytes_with_budget( bytes: &[u8], budget: usize, ) -> Result<Self, DeserializationError>

Deserializes Self from bytes with a byte budget limit.

impl Eq for BlockHeader

impl PartialEq for BlockHeader

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serializable for BlockHeader

fn write_into<W: ByteWriter>(&self, target: &mut W)

Serializes self into bytes and writes these bytes into the target.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

impl StructuralPartialEq for BlockHeader