Struct zebra_rpc::methods::get_block_template_rpcs::types::long_poll::LongPollId

pub struct LongPollId {
    pub tip_height: u32,
    pub tip_hash_checksum: u32,
    pub max_timestamp: u32,
    pub mempool_transaction_count: u32,
    pub mempool_transaction_content_checksum: u32,
}

The encoded long poll ID, generated from the LongPollInput.

zcashd IDs are currently 69 hex/decimal digits long. Since Zebra’s IDs are only 46 hex/decimal digits, mining pools should be able to handle them.

Fields

tip_height: u32

The tip height used to generate the template containing this long poll ID.

If the tip block height changes, a new template must be provided. Old work is no longer valid.

The height is technically redundant, but it helps with debugging. It also reduces the probability of a missed tip change.

tip_hash_checksum: u32

A checksum of the tip hash used to generate the template containing this long poll ID.

If the tip block changes, a new template must be provided. Old work is no longer valid. This checksum is not cryptographically secure.

It’s ok to do a probabilistic check here, so we choose a 1 in 2^32 chance of missing a block change.

max_timestamp: u32

The max time in the same template as this long poll ID.

If the max time is reached, a new template must be provided. Old work is no longer valid.

Ideally, a new template should be provided at least one target block interval before the max time. This avoids wasted work.

Zcash times are limited to 32 bits by the consensus rules.

mempool_transaction_count: u32

The number of transactions in the mempool when the template containing this long poll ID was generated. This might be different from the number of transactions in the template, due to ZIP-317.

If the number of mempool transactions changes, a new template might be provided. Old work is still valid.

The number of transactions is limited by the mempool DoS limit.

Using the number of transactions makes mempool checksum attacks much harder. It also helps with debugging, and reduces the probability of a missed mempool change.

mempool_transaction_content_checksum: u32

A checksum of the effecting hashes of the transactions in the mempool, when the template containing this long poll ID was generated. We ignore changes to authorizing data.

This might be different from the transactions in the template, due to ZIP-317.

If the content of the mempool changes, a new template might be provided. Old work is still valid.

This checksum is not cryptographically secure.

It’s ok to do a probabilistic check here, so we choose a 1 in 2^32 chance of missing a transaction change.

Security

Attackers could use dust transactions to keep the checksum at the same value. But this would likely change the number of transactions in the mempool.

If an attacker could also keep the number of transactions constant, a new template will be generated when the tip hash changes, or the max time is reached.

Implementations

impl LongPollId

pub fn submit_old(&self, old_long_poll_id: &LongPollId) -> bool

Returns true if shares using old_long_poll_id can be submitted in response to the template for self: https://en.bitcoin.it/wiki/BIP_0022#Optional:_Long_Polling

Old shares may be valid if only the mempool transactions have changed, because newer transactions don’t have to be included in the old shares.

But if the chain tip has changed, the block header has changed, so old shares are invalid. (And if the max time has changed on testnet, the block header has changed.)

Trait Implementations

impl Clone for LongPollId

fn clone(&self) -> LongPollId

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LongPollId

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for LongPollId

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for LongPollId

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

Formats the value using the given formatter.

impl From<LongPollId> for String

fn from(id: LongPollId) -> Self

Converts to this type from the input type.

impl FromStr for LongPollId

fn from_str(long_poll_id: &str) -> Result<Self, Self::Err>

Exact conversion from a string to LongPollId.

type Err = Box<dyn Error + Sync + Send>

The associated error which can be returned from parsing.

impl PartialEq for LongPollId

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for LongPollId

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFrom<String> for LongPollId

type Error = Box<dyn Error + Sync + Send>

The type returned in the event of a conversion error.

fn try_from(s: String) -> Result<Self, Self::Error>

Performs the conversion.

impl Copy for LongPollId

impl Eq for LongPollId

impl StructuralPartialEq for LongPollId