proof_system::honk::BaseTranscript Class Reference

Common transcript class for both parties. Stores the data for the current round, as well as the manifest. More...

#include <transcript.hpp>

Inheritance diagram for proof_system::honk::BaseTranscript:

Public Types
using	Proof = std::vector< uint8_t >

Public Member Functions
	BaseTranscript (const Proof &proof_data)
	Construct a new Base Transcript object for Verifier using proof_data.
std::vector< uint8_t >	export_proof ()
	Return the proof data starting at proof_start.
void	load_proof (const std::vector< uint8_t > &proof)
template<typename... Strings>
std::array< uint256_t, sizeof...(Strings)>	get_challenges (const Strings &... labels)
	After all the prover messages have been sent, finalize the round by hashing all the data and then create the number of requested challenges.
template<class T >
void	send_to_verifier (const std::string &label, const T &element)
	Adds a prover message to the transcript, only intended to be used by the prover.
template<class T >
T	receive_from_prover (const std::string &label)
	Reads the next element of type T from the transcript, with a predefined label, only used by verifier.
uint256_t	get_challenge (const std::string &label)
TranscriptManifest	get_manifest () const
void	print ()

Static Public Member Functions
static std::shared_ptr< BaseTranscript >	prover_init_empty ()
	For testing: initializes transcript with some arbitrary data so that a challenge can be generated after initialization. Only intended to be used by Prover.
static std::shared_ptr< BaseTranscript >	verifier_init_empty (const std::shared_ptr< BaseTranscript > &transcript)
	For testing: initializes transcript based on proof data then receives junk data produced by BaseTranscript::prover_init_empty(). Only intended to be used by Verifier.

Public Attributes
std::ptrdiff_t	proof_start = 0
size_t	num_bytes_written = 0
size_t	num_bytes_read = 0
size_t	round_number = 0
Proof	proof_data

Static Public Attributes
static constexpr size_t	HASH_OUTPUT_SIZE = 32

Protected Member Functions
void	consume_prover_element_bytes (const std::string &label, std::span< const uint8_t > element_bytes)
	Adds challenge elements to the current_round_buffer and updates the manifest.
template<typename T >
void	serialize_to_buffer (const T &element, Proof &proof_data)
	Serializes object and appends it to proof_data.
template<typename T >
T	deserialize_from_buffer (const Proof &proof_data, size_t &offset) const
	Deserializes the bytes starting at offset into the typed element and returns that element.

Detailed Description

Common transcript class for both parties. Stores the data for the current round, as well as the manifest.

Constructor & Destructor Documentation

BaseTranscript()

proof_system::honk::BaseTranscript::BaseTranscript ( const Proof &  proof_data )

inlineexplicit

Construct a new Base Transcript object for Verifier using proof_data.

Parameters

proof_data

Member Function Documentation

consume_prover_element_bytes()

void proof_system::honk::BaseTranscript::consume_prover_element_bytes ( const std::string &  label, std::span< const uint8_t >  element_bytes  )

inlineprotected

Adds challenge elements to the current_round_buffer and updates the manifest.

Parameters

label	of the element sent
element_bytes	serialized

deserialize_from_buffer()

template<typename T >

T proof_system::honk::BaseTranscript::deserialize_from_buffer ( const Proof &  proof_data, size_t &  offset  ) const

inlineprotected

Deserializes the bytes starting at offset into the typed element and returns that element.

Using the template parameter and the offset argument, this function deserializes the bytes with from_buffer and then increments the offset appropriately based on the number of bytes that were deserialized.

Template Parameters

T

Parameters

proof_data
offset

Returns

T

export_proof()

std::vector< uint8_t > proof_system::honk::BaseTranscript::export_proof ( )

inline

Return the proof data starting at proof_start.

This is useful for when two different provers share a transcript.

get_challenges()

template<typename... Strings>

std::array< uint256_t, sizeof...(Strings)> proof_system::honk::BaseTranscript::get_challenges ( const Strings &...  labels )

inline

After all the prover messages have been sent, finalize the round by hashing all the data and then create the number of requested challenges.

Challenges are generated by iteratively hashing over the previous challenge, using get_next_challenge_buffer(). TODO(#741): Optimizations for this function include generalizing type of hash, splitting hashes into multiple challenges.

Parameters

labels

human-readable names for the challenges for the manifest

Returns

std::array<uint256_t, num_challenges> challenges for this round.

prover_init_empty()

static std::shared_ptr< BaseTranscript > proof_system::honk::BaseTranscript::prover_init_empty ( )

inlinestatic

For testing: initializes transcript with some arbitrary data so that a challenge can be generated after initialization. Only intended to be used by Prover.

Returns

BaseTranscript

receive_from_prover()

template<class T >

T proof_system::honk::BaseTranscript::receive_from_prover ( const std::string &  label )

inline

Reads the next element of type T from the transcript, with a predefined label, only used by verifier.

Parameters

label

Human readable name for the challenge.

Returns

deserialized element of type T

send_to_verifier()

template<class T >

void proof_system::honk::BaseTranscript::send_to_verifier ( const std::string &  label, const T &  element  )

inline

Adds a prover message to the transcript, only intended to be used by the prover.

Serializes the provided object into proof_data, and updates the current round state in consume_prover_element_bytes.

Parameters

label	Description/name of the object being added.
element	Serializable object that will be added to the transcript

Todo:

Use a concept to only allow certain types to be passed. Requirements are that the object should be serializable.

serialize_to_buffer()

template<typename T >

void proof_system::honk::BaseTranscript::serialize_to_buffer ( const T &  element, Proof &  proof_data  )

inlineprotected

Serializes object and appends it to proof_data.

Calls to_buffer on element to serialize, and modifies proof_data object by appending the serialized bytes to it.

Template Parameters

T

Parameters

element
proof_data

verifier_init_empty()

static std::shared_ptr< BaseTranscript > proof_system::honk::BaseTranscript::verifier_init_empty ( const std::shared_ptr< BaseTranscript > &  transcript )

inlinestatic

For testing: initializes transcript based on proof data then receives junk data produced by BaseTranscript::prover_init_empty(). Only intended to be used by Verifier.

Parameters

transcript

Returns

BaseTranscript

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

• src/barretenberg/transcript/transcript.hpp