crypto::pedersen_hash_base< Curve > Class Template Reference

Performs pedersen hashes! More...

#include <pedersen.hpp>

Public Types
using	AffineElement = typename Curve::AffineElement
using	Element = typename Curve::Element
using	Fq = typename Curve::BaseField
using	Fr = typename Curve::ScalarField
using	Group = typename Curve::Group
using	GeneratorContext = typename crypto::GeneratorContext< Curve >

Static Public Member Functions
static Fq	hash (const std::vector< Fq > &inputs, GeneratorContext context={})
	Given a vector of fields, generate a pedersen hash using generators from context.
static Fq	hash_buffer (const std::vector< uint8_t > &input, GeneratorContext context={})
	Given an arbitrary length of bytes, convert them to fields and hash the result using the default generators.

Static Public Attributes
static constexpr AffineElement	length_generator = Group::derive_generators("pedersen_hash_length", 1)[0]

Detailed Description

template<typename Curve>
class crypto::pedersen_hash_base< Curve >

Performs pedersen hashes!

To hash to a size-n list of field elements x, we return the X-coordinate of:

 Hash(x) = n.[h] + Commit(x)

Where g is a list of generator points defined by generator_data And h is a unique generator whose domain separator is the string pedersen_hash_length.

The addition of n.[h] into the hash is to prevent length-extension attacks. It also ensures that the hash output is never the point at infinity.

It is neccessary that all generator points are linearly independent of one another, so that finding collisions is equivalent to solving the discrete logarithm problem. This is ensured via the generator derivation algorithm in generator_data

Member Function Documentation

hash()

template<typename Curve >

Curve::BaseField crypto::pedersen_hash_base< Curve >::hash ( const std::vector< Fq > &  inputs, GeneratorContext  context = {}  )

static

Given a vector of fields, generate a pedersen hash using generators from context.

context.offset is used to access offset elements of context.generators if required. e.g. if one desires to compute inputs[0] * [generators[hash_index]] +inputs[1] * [generators[hash_index + 1]]` + ... etc Potentially useful to ensure multiple hashes with the same domain separator cannot collide.

Parameters

inputs	what are we hashing?
context	Stores generator metadata + context pointer to the generators we are using for this hash

Returns

Fq (i.e. SNARK circuit scalar field, when hashing using a curve defined over the SNARK circuit scalar field)

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The documentation for this class was generated from the following files:

• src/barretenberg/crypto/pedersen_hash/pedersen.hpp
• src/barretenberg/crypto/pedersen_hash/pedersen.cpp