logo
pub struct Header {
    pub version: u32,
    pub previous_block_hash: Hash,
    pub merkle_root: Root,
    pub commitment_bytes: [u8; 32],
    pub time: DateTime<Utc>,
    pub difficulty_threshold: CompactDifficulty,
    pub nonce: [u8; 32],
    pub solution: Solution,
}
Expand description

A block header, containing metadata about a block.

How are blocks chained together? They are chained together via the backwards reference (previous header hash) present in the block header. Each block points backwards to its parent, all the way back to the genesis block (the first block in the blockchain).

Fields

version: u32

The block’s version field. This is supposed to be 4:

The current and only defined block version number for Zcash is 4.

but this was not enforced by the consensus rules, and defective mining software created blocks with other versions, so instead it’s effectively a free field. The only constraint is that it must be at least 4 when interpreted as an i32.

previous_block_hash: Hash

The hash of the previous block, used to create a chain of blocks back to the genesis block.

This ensures no previous block can be changed without also changing this block’s header.

merkle_root: Root

The root of the Bitcoin-inherited transaction Merkle tree, binding the block header to the transactions in the block.

Note that because of a flaw in Bitcoin’s design, the merkle_root does not always precisely bind the contents of the block (CVE-2012-2459). It is sometimes possible for an attacker to create multiple distinct sets of transactions with the same Merkle root, although only one set will be valid.

commitment_bytes: [u8; 32]

Zcash blocks contain different kinds of commitments to their contents, depending on the network and height.

The interpretation of this field has been changed multiple times, without incrementing the block version. Therefore, this field cannot be parsed without the network and height. Use Block::commitment to get the parsed Commitment.

time: DateTime<Utc>

The block timestamp is a Unix epoch time (UTC) when the miner started hashing the header (according to the miner).

difficulty_threshold: CompactDifficulty

An encoded version of the target threshold this block’s header hash must be less than or equal to, in the same nBits format used by Bitcoin.

For a block at block height height, bits MUST be equal to ThresholdBits(height).

Bitcoin-nBits

nonce: [u8; 32]

An arbitrary field that miners can change to modify the header hash in order to produce a hash less than or equal to the target threshold.

solution: Solution

The Equihash solution.

Implementations

TODO: Inline this function into zebra_consensus::block::check::time_is_valid_at. See https://github.com/ZcashFoundation/zebra/issues/1021 for more details.

Trait Implementations

The type of parameters that arbitrary_with accepts for configuration of the generated Strategy. Parameters must implement Default. Read more
Generates a Strategy for producing arbitrary values of type the implementing type (Self). The strategy is passed the arguments given in args. Read more
The type of Strategy used to generate values of type Self. Read more
Generates a Strategy for producing arbitrary values of type the implementing type (Self). Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Deserialize this value from the given Serde deserializer. Read more
Converts to this type from the input type.
Converts to this type from the input type.
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
Serialize this value into the given Serde serializer. Read more
Try to read self from the given reader. Read more
Write self to the given writer using the canonical format. Read more
Helper function to construct a vec to serialize the current struct into
Get the size of self by using a fake writer.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Converts self into T using Into<T>. Read more
Compare self to key and return true if they are equal.
Causes self to use its Binary implementation when Debug-formatted. Read more
Causes self to use its Display implementation when Debug-formatted. Read more
Causes self to use its LowerExp implementation when Debug-formatted. Read more
Causes self to use its LowerHex implementation when Debug-formatted. Read more
Causes self to use its Octal implementation when Debug-formatted. Read more
Causes self to use its Pointer implementation when Debug-formatted. Read more
Causes self to use its UpperExp implementation when Debug-formatted. Read more
Causes self to use its UpperHex implementation when Debug-formatted. Read more
Formats each item in a sequence. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more
Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Set the foreground color generically Read more
Set the background color generically. Read more
Change the foreground color to black
Change the background color to black
Change the foreground color to red
Change the background color to red
Change the foreground color to green
Change the background color to green
Change the foreground color to yellow
Change the background color to yellow
Change the foreground color to blue
Change the background color to blue
Change the foreground color to magenta
Change the background color to magenta
Change the foreground color to purple
Change the background color to purple
Change the foreground color to cyan
Change the background color to cyan
Change the foreground color to white
Change the background color to white
Change the foreground color to the terminal default
Change the background color to the terminal default
Change the foreground color to bright black
Change the background color to bright black
Change the foreground color to bright red
Change the background color to bright red
Change the foreground color to bright green
Change the background color to bright green
Change the foreground color to bright yellow
Change the background color to bright yellow
Change the foreground color to bright blue
Change the background color to bright blue
Change the foreground color to bright magenta
Change the background color to bright magenta
Change the foreground color to bright purple
Change the background color to bright purple
Change the foreground color to bright cyan
Change the background color to bright cyan
Change the foreground color to bright white
Change the background color to bright white
Make the text bold
Make the text dim
Make the text italicized
Make the text italicized
Make the text blink
Make the text blink (but fast!)
Swap the foreground and background colors
Hide the text
Cross out the text
Set the foreground color at runtime. Only use if you do not know which color will be used at compile-time. If the color is constant, use either OwoColorize::fg or a color-specific method, such as OwoColorize::green, Read more
Set the background color at runtime. Only use if you do not know what color to use at compile-time. If the color is constant, use either OwoColorize::bg or a color-specific method, such as OwoColorize::on_yellow, Read more
Set the foreground color to a specific RGB value.
Set the background color to a specific RGB value.
Sets the foreground color to an RGB value.
Sets the background color to an RGB value.
Apply a runtime-determined style
Pipes by value. This is generally the method you want to use. Read more
Borrows self and passes that borrow into the pipe function. Read more
Mutably borrows self and passes that borrow into the pipe function. Read more
Borrows self, then passes self.borrow() into the pipe function. Read more
Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more
Borrows self, then passes self.as_ref() into the pipe function.
Mutably borrows self, then passes self.as_mut() into the pipe function. Read more
Borrows self, then passes self.deref() into the pipe function.
Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more
The alignment of pointer.
The type for initializers.
Initializes a with the given initializer. Read more
Dereferences the given pointer. Read more
Mutably dereferences the given pointer. Read more
Drops the object pointed to by the given pointer. Read more
Converts the type into a Result that can be sent as a response.
Should always be Self
Immutable access to a value. Read more
Mutable access to a value. Read more
Immutable access to the Borrow<B> of a value. Read more
Mutable access to the BorrowMut<B> of a value. Read more
Immutable access to the AsRef<R> view of a value. Read more
Mutable access to the AsMut<R> view of a value. Read more
Immutable access to the Deref::Target of a value. Read more
Mutable access to the Deref::Target of a value. Read more
Calls .tap() only in debug builds, and is erased in release builds.
Calls .tap_mut() only in debug builds, and is erased in release builds. Read more
Calls .tap_borrow() only in debug builds, and is erased in release builds. Read more
Calls .tap_borrow_mut() only in debug builds, and is erased in release builds. Read more
Calls .tap_ref() only in debug builds, and is erased in release builds. Read more
Calls .tap_ref_mut() only in debug builds, and is erased in release builds. Read more
Calls .tap_deref() only in debug builds, and is erased in release builds. Read more
Calls .tap_deref_mut() only in debug builds, and is erased in release builds. Read more
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Attempts to convert self into T using TryInto<T>. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more