Struct hash2curve::DomainSeparationTag

pub struct DomainSeparationTag { /* fields omitted */ }

Represents a domain separation tag suitable for use in hash_to_curve or encode_to_curve functions as describe in section 3.1 in https://datatracker.ietf.org/doc/draft-irtf-cfrg-hash-to-curve/?include_text=1

As an example, consider a fictional protocol named Quux that defines several different ciphersuites. A reasonable choice of tag is "QUUX- V-CS", where and are two-digit numbers indicating the version and ciphersuite, respectively.

As another example, consider a fictional protocol named Baz that requires two independent random oracles, where one oracle outputs points on the curve E1 and the other outputs points on the curve E2. Reasonable choices of tags for the E1 and E2 oracles are "BAZ-V- CS-E1" and "BAZ-V-CS-E2", respectively, where and are as described above.

use hash2curve::DomainSeparationTag;

let dst = DomainSeparationTag::new(b"MySuperAwesomeProtocol", None, None, None);

assert!(dst.is_ok());

let dst = DomainSeparationTag::new(b"", None, None, None);

assert!(dst.is_err());

Methods

impl DomainSeparationTag

pub fn new(
    protocol_id: &[u8],
    protocol_version: Option<&[u8]>,
    ciphersuite_id: Option<&[u8]>,
    encoding_id: Option<&[u8]>
) -> Result<Self, HashingError>

Convenience function for creating a domain separation tag

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

Convert the tag to bytes. All fields cannot be longer than 255 bytes in length If a domain separation tag longer than 255 bytes must be used (e.g., because of requirements imposed by an invoking protocol), this computes the H("H2C-OVERSIZE-DST-" || protocol_id || procotol_version || ciphersuite_id || encoding_id) D must be a cryptographically secure hash function like SHA256, SHA3-256, or BLAKE2.

Trait Implementations

impl Clone for DomainSeparationTag

fn clone(&self) -> DomainSeparationTag

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for DomainSeparationTag

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

Formats the value using the given formatter.

impl Eq for DomainSeparationTag

impl From<DomainSeparationTag> for Bls12381G1Sswu

fn from(dst: DomainSeparationTag) -> Self

Performs the conversion.

impl PartialEq<DomainSeparationTag> for DomainSeparationTag

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

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

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

This method tests for !=.

impl StructuralEq for DomainSeparationTag

impl StructuralPartialEq for DomainSeparationTag