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 bb::BaseTranscript< Codec_, HashFunction_ >:

Public Types
using	Codec = Codec_

using	HashFunction = HashFunction_

using	DataType = typename Codec::DataType

using	Proof = std::vector< DataType >

Public Member Functions
	BaseTranscript ()

	BaseTranscript (const Proof &proof)

std::vector< DataType >	export_proof ()
	Return the proof data starting at proof_start.

void	load_proof (const std::vector< DataType > &proof)
	Verifier-specific method. The verifier needs to load a proof or its segment before the verification.

size_t	get_proof_size ()

void	enable_manifest ()

template<typename ChallengeType >
std::vector< ChallengeType >	get_challenges (std::span< const std::string > 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<typename ChallengeType , size_t N>
std::array< ChallengeType, N >	get_challenges (const std::array< std::string, N > &labels)
	Wrapper around get_challenges to handle array of challenges.

template<typename ChallengeType >
std::vector< ChallengeType >	get_dyadic_powers_of_challenge (const std::string &label, size_t num_challenges)
	Get a challenge and compute its dyadic powers [δ, δ², δ⁴, ..., δ^(2^(num_challenges-1))].

template<class T >
void	add_to_hash_buffer (const std::string &label, const T &element)
	Adds an element to the transcript.

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.

template<typename ChallengeType >
ChallengeType	get_challenge (const std::string &label)

TranscriptManifest	get_manifest () const

void	print ()

void	test_set_proof_parsing_state (std::ptrdiff_t start, size_t written)
	Test utility: Set proof parsing state for export after deserialization.

std::ptrdiff_t	test_get_proof_start () const
	Test utility: Get proof_start for validation.

Static Public Member Functions
static std::shared_ptr< BaseTranscript >	convert_prover_transcript_to_verifier_transcript (const std::shared_ptr< BaseTranscript > &prover_transcript)
	Convert a prover transcript to a verifier transcript.

template<typename T >
static std::vector< DataType >	serialize (const T &element)

template<typename T >
static T	deserialize (std::span< const DataType > frs)

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.

Static Public Attributes
static constexpr bool	in_circuit = InCircuit<DataType>

static constexpr size_t	CHALLENGE_BUFFER_SIZE = 2

Protected Member Functions
void	add_element_frs_to_hash_buffer (const std::string &label, std::span< const DataType > element_frs)
	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 frs starting at offset into the typed element and returns that element.

Protected Attributes
Proof	proof_data

Private Member Functions
std::array< DataType, CHALLENGE_BUFFER_SIZE >	get_next_duplex_challenge_buffer ()
	Compute next challenge c_next = H( Compress(c_prev \|\| round_buffer) )

Private Attributes
size_t	transcript_index = 0

size_t	round_index = 0

bool	reception_phase = true

bool	is_first_challenge = true

DataType	previous_challenge {}

std::vector< DataType >	current_round_data

std::ptrdiff_t	proof_start = 0

size_t	num_frs_written = 0

size_t	num_frs_read = 0

size_t	round_number = 0

bool	use_manifest = false

TranscriptManifest	manifest

Friends
template<typename T >
OriginTag	bb::extract_transcript_tag (const T &transcript)

Detailed Description

template<typename Codec_, typename HashFunction_>
class bb::BaseTranscript< Codec_, HashFunction_ >

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

Definition at line 41 of file transcript.hpp.

Member Typedef Documentation

◆ Codec

template<typename Codec_ , typename HashFunction_ >

using bb::BaseTranscript< Codec_, HashFunction_ >::Codec = Codec_

Definition at line 43 of file transcript.hpp.

◆ DataType

template<typename Codec_ , typename HashFunction_ >

using bb::BaseTranscript< Codec_, HashFunction_ >::DataType = typename Codec::DataType

Definition at line 45 of file transcript.hpp.

◆ HashFunction

template<typename Codec_ , typename HashFunction_ >

using bb::BaseTranscript< Codec_, HashFunction_ >::HashFunction = HashFunction_

Definition at line 44 of file transcript.hpp.

◆ Proof

template<typename Codec_ , typename HashFunction_ >

using bb::BaseTranscript< Codec_, HashFunction_ >::Proof = std::vector<DataType>

Definition at line 46 of file transcript.hpp.

Constructor & Destructor Documentation

◆ BaseTranscript() [1/2]

template<typename Codec_ , typename HashFunction_ >

bb::BaseTranscript< Codec_, HashFunction_ >::BaseTranscript ( )

inline

Definition at line 53 of file transcript.hpp.

◆ BaseTranscript() [2/2]

template<typename Codec_ , typename HashFunction_ >

bb::BaseTranscript< Codec_, HashFunction_ >::BaseTranscript ( const Proof & proof )

inlineexplicit

Definition at line 62 of file transcript.hpp.

Member Function Documentation

◆ add_element_frs_to_hash_buffer()

template<typename Codec_ , typename HashFunction_ >

void bb::BaseTranscript< Codec_, HashFunction_ >::add_element_frs_to_hash_buffer	(	const std::string &	label,
		std::span< const DataType >	element_frs
	)

inlineprotected

Adds challenge elements to the current_round_buffer and updates the manifest.

Parameters

label	of the element sent
element_frs	serialized

Definition at line 140 of file transcript.hpp.

◆ add_to_hash_buffer()

template<typename Codec_ , typename HashFunction_ >

template<class T >

void bb::BaseTranscript< Codec_, HashFunction_ >::add_to_hash_buffer	(	const std::string &	label,
		const T &	element
	)

inline

Adds an element to the transcript.

Serializes the element to frs and adds it to the current_round_data buffer. Does NOT add the element to the proof.

Parameters

label	Human-readable name for the challenge.
element	Element to be added.

Definition at line 320 of file transcript.hpp.

◆ convert_prover_transcript_to_verifier_transcript()

template<typename Codec_ , typename HashFunction_ >

static std::shared_ptr< BaseTranscript > bb::BaseTranscript< Codec_, HashFunction_ >::convert_prover_transcript_to_verifier_transcript ( const std::shared_ptr< BaseTranscript< Codec_, HashFunction_ > > & prover_transcript )

inlinestatic

Convert a prover transcript to a verifier transcript.

Parameters

prover_transcript The prover transcript to convert

Returns: std::shared_ptr<BaseTranscript> The verifier transcript

Definition at line 411 of file transcript.hpp.

◆ deserialize()

template<typename Codec_ , typename HashFunction_ >

template<typename T >

static T bb::BaseTranscript< Codec_, HashFunction_ >::deserialize ( std::span< const DataType > frs )

inlinestatic

Definition at line 428 of file transcript.hpp.

◆ deserialize_from_buffer()

template<typename Codec_ , typename HashFunction_ >

template<typename T >

T bb::BaseTranscript< Codec_, HashFunction_ >::deserialize_from_buffer	(	const Proof &	proof_data,
		size_t &	offset
	)		const

inlineprotected

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

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

Template Parameters

T

Parameters

proof_data
offset

Returns: T

Definition at line 172 of file transcript.hpp.

◆ enable_manifest()

template<typename Codec_ , typename HashFunction_ >

void bb::BaseTranscript< Codec_, HashFunction_ >::enable_manifest ( )

inline

Definition at line 216 of file transcript.hpp.

◆ export_proof()

template<typename Codec_ , typename HashFunction_ >

std::vector< DataType > bb::BaseTranscript< Codec_, HashFunction_ >::export_proof ( )

inline

Return the proof data starting at proof_start.

This function returns the elements of the transcript in the interval [proof_start : proof_start + num_frs_written] and then updates proof_start. It is useful for when two provers share a transcript, as calling export_proof at the end of each provers' code returns the slices T_1, T_2 of the transcript that must be loaded by the verifiers via load_proof.

Definition at line 193 of file transcript.hpp.

◆ get_challenge()

template<typename Codec_ , typename HashFunction_ >

template<typename ChallengeType >

ChallengeType bb::BaseTranscript< Codec_, HashFunction_ >::get_challenge ( const std::string & label )

inline

Definition at line 396 of file transcript.hpp.

◆ get_challenges() [1/2]

template<typename Codec_ , typename HashFunction_ >

template<typename ChallengeType , size_t N>

std::array< ChallengeType, N > bb::BaseTranscript< Codec_, HashFunction_ >::get_challenges ( const std::array< std::string, N > & labels )

inline

Wrapper around get_challenges to handle array of challenges.

Parameters

array of labels human-readable names for the challenges for the manifest

Returns: std::array<ChallengeType, N> challenges for this round.

Definition at line 283 of file transcript.hpp.

◆ get_challenges() [2/2]

template<typename Codec_ , typename HashFunction_ >

template<typename ChallengeType >

std::vector< ChallengeType > bb::BaseTranscript< Codec_, HashFunction_ >::get_challenges ( std::span< const std::string > 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(). Note that the pairs of challenges will be 127 bits each, as in they will be [127, 127, 127, 127, ...].

Parameters

labels human-readable names for the challenges for the manifest

Returns: std::vector<ChallengeType> challenges for this round.

Definition at line 228 of file transcript.hpp.

◆ get_dyadic_powers_of_challenge()

template<typename Codec_ , typename HashFunction_ >

template<typename ChallengeType >

std::vector< ChallengeType > bb::BaseTranscript< Codec_, HashFunction_ >::get_dyadic_powers_of_challenge	(	const std::string &	label,
		size_t	num_challenges
	)

inline

Get a challenge and compute its dyadic powers [δ, δ², δ⁴, ..., δ^(2^(num_challenges-1))].

Generates num_challenges elements where each element is the square of the previous one. This is Step 2 of the protocol as written in the Protogalaxy paper.

Parameters

label	Human-readable name for the challenge
num_challenges	Number of power-of-2 powers to generate

Returns: Vector of num_challenges elements: [δ, δ², δ⁴, δ⁸, ...]

Definition at line 301 of file transcript.hpp.

◆ get_manifest()

template<typename Codec_ , typename HashFunction_ >

TranscriptManifest bb::BaseTranscript< Codec_, HashFunction_ >::get_manifest ( ) const

inline

Definition at line 459 of file transcript.hpp.

◆ get_next_duplex_challenge_buffer()

template<typename Codec_ , typename HashFunction_ >

std::array< DataType, CHALLENGE_BUFFER_SIZE > bb::BaseTranscript< Codec_, HashFunction_ >::get_next_duplex_challenge_buffer ( )

inlineprivate

Compute next challenge c_next = H( Compress(c_prev || round_buffer) )

This function computes a new challenge for the current round using the previous challenge and the current round data, if they exist. It clears the current_round_data if nonempty after computing the challenge to minimize how much we compress. It also sets previous_challenge to the current challenge buffer to set up next function call.

Returns: std::array<DataType, CHALLENGE_BUFFER_SIZE>

Definition at line 99 of file transcript.hpp.

◆ get_proof_size()

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::get_proof_size ( )

inline

Definition at line 213 of file transcript.hpp.

◆ load_proof()

template<typename Codec_ , typename HashFunction_ >

void bb::BaseTranscript< Codec_, HashFunction_ >::load_proof ( const std::vector< DataType > & proof )

inline

Verifier-specific method. The verifier needs to load a proof or its segment before the verification.

Parameters

proof

Definition at line 207 of file transcript.hpp.

◆ print()

template<typename Codec_ , typename HashFunction_ >

void bb::BaseTranscript< Codec_, HashFunction_ >::print ( )

inline

Definition at line 461 of file transcript.hpp.

◆ prover_init_empty()

template<typename Codec_ , typename HashFunction_ >

static std::shared_ptr< BaseTranscript > bb::BaseTranscript< Codec_, HashFunction_ >::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

Definition at line 438 of file transcript.hpp.

◆ receive_from_prover()

template<typename Codec_ , typename HashFunction_ >

template<class T >

T bb::BaseTranscript< Codec_, HashFunction_ >::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

Definition at line 367 of file transcript.hpp.

◆ send_to_verifier()

template<typename Codec_ , typename HashFunction_ >

template<class T >

void bb::BaseTranscript< Codec_, HashFunction_ >::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 add_element_frs_to_hash_buffer.

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.

Definition at line 350 of file transcript.hpp.

◆ serialize()

template<typename Codec_ , typename HashFunction_ >

template<typename T >

static std::vector< DataType > bb::BaseTranscript< Codec_, HashFunction_ >::serialize ( const T & element )

inlinestatic

Definition at line 423 of file transcript.hpp.

◆ serialize_to_buffer()

template<typename Codec_ , typename HashFunction_ >

template<typename T >

void bb::BaseTranscript< Codec_, HashFunction_ >::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 frs to it.

Template Parameters

T

Parameters

element
proof_data

Definition at line 158 of file transcript.hpp.

◆ test_get_proof_start()

template<typename Codec_ , typename HashFunction_ >

std::ptrdiff_t bb::BaseTranscript< Codec_, HashFunction_ >::test_get_proof_start ( ) const

inline

Test utility: Get proof_start for validation.

Used by test fixtures to verify transcript conversion

Definition at line 485 of file transcript.hpp.

◆ test_set_proof_parsing_state()

template<typename Codec_ , typename HashFunction_ >

void bb::BaseTranscript< Codec_, HashFunction_ >::test_set_proof_parsing_state	(	std::ptrdiff_t	start,
		size_t	written
	)

inline

Test utility: Set proof parsing state for export after deserialization.

Used by test utilities that need to re-export proofs after tampering

Definition at line 475 of file transcript.hpp.

◆ verifier_init_empty()

template<typename Codec_ , typename HashFunction_ >

static std::shared_ptr< BaseTranscript > bb::BaseTranscript< Codec_, HashFunction_ >::verifier_init_empty ( const std::shared_ptr< BaseTranscript< Codec_, HashFunction_ > > & 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

Definition at line 453 of file transcript.hpp.

Friends And Related Symbol Documentation

◆ bb::extract_transcript_tag

template<typename Codec_ , typename HashFunction_ >

template<typename T >

OriginTag bb::extract_transcript_tag ( const T & transcript )

friend

Member Data Documentation

◆ CHALLENGE_BUFFER_SIZE

template<typename Codec_ , typename HashFunction_ >

constexpr size_t bb::BaseTranscript< Codec_, HashFunction_ >::CHALLENGE_BUFFER_SIZE = 2

staticconstexpr

Definition at line 51 of file transcript.hpp.

◆ current_round_data

template<typename Codec_ , typename HashFunction_ >

std::vector<DataType> bb::BaseTranscript< Codec_, HashFunction_ >::current_round_data

private

Definition at line 79 of file transcript.hpp.

◆ in_circuit

template<typename Codec_ , typename HashFunction_ >

constexpr bool bb::BaseTranscript< Codec_, HashFunction_ >::in_circuit = InCircuit<DataType>

staticconstexpr

Definition at line 49 of file transcript.hpp.

◆ is_first_challenge

template<typename Codec_ , typename HashFunction_ >

bool bb::BaseTranscript< Codec_, HashFunction_ >::is_first_challenge = true

private

Definition at line 77 of file transcript.hpp.

◆ manifest

template<typename Codec_ , typename HashFunction_ >

TranscriptManifest bb::BaseTranscript< Codec_, HashFunction_ >::manifest

private

Definition at line 89 of file transcript.hpp.

◆ num_frs_read

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::num_frs_read = 0

private

Definition at line 84 of file transcript.hpp.

◆ num_frs_written

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::num_frs_written = 0

private

Definition at line 83 of file transcript.hpp.

◆ previous_challenge

template<typename Codec_ , typename HashFunction_ >

DataType bb::BaseTranscript< Codec_, HashFunction_ >::previous_challenge {}

private

Definition at line 78 of file transcript.hpp.

◆ proof_data

template<typename Codec_ , typename HashFunction_ >

Proof bb::BaseTranscript< Codec_, HashFunction_ >::proof_data

protected

Definition at line 65 of file transcript.hpp.

◆ proof_start

template<typename Codec_ , typename HashFunction_ >

std::ptrdiff_t bb::BaseTranscript< Codec_, HashFunction_ >::proof_start = 0

private

Definition at line 82 of file transcript.hpp.

◆ reception_phase

template<typename Codec_ , typename HashFunction_ >

bool bb::BaseTranscript< Codec_, HashFunction_ >::reception_phase = true

private

Definition at line 74 of file transcript.hpp.

◆ round_index

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::round_index = 0

private

Definition at line 73 of file transcript.hpp.

◆ round_number

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::round_number = 0

private

Definition at line 85 of file transcript.hpp.

◆ transcript_index

template<typename Codec_ , typename HashFunction_ >

size_t bb::BaseTranscript< Codec_, HashFunction_ >::transcript_index = 0

private

Definition at line 72 of file transcript.hpp.

◆ use_manifest

template<typename Codec_ , typename HashFunction_ >

bool bb::BaseTranscript< Codec_, HashFunction_ >::use_manifest = false

private

Definition at line 88 of file transcript.hpp.

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

src/barretenberg/transcript/transcript.hpp

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Friends

Detailed Description

Member Typedef Documentation

◆ Codec

◆ DataType

◆ HashFunction

◆ Proof

Constructor & Destructor Documentation

◆ BaseTranscript() [1/2]

◆ BaseTranscript() [2/2]

Member Function Documentation

◆ add_element_frs_to_hash_buffer()

◆ add_to_hash_buffer()

◆ convert_prover_transcript_to_verifier_transcript()

◆ deserialize()

◆ deserialize_from_buffer()

◆ enable_manifest()

◆ export_proof()

◆ get_challenge()

◆ get_challenges() [1/2]

◆ get_challenges() [2/2]

◆ get_dyadic_powers_of_challenge()

◆ get_manifest()

◆ get_next_duplex_challenge_buffer()

◆ get_proof_size()

◆ load_proof()

◆ print()

◆ prover_init_empty()

◆ receive_from_prover()

◆ send_to_verifier()

◆ serialize()

◆ serialize_to_buffer()

◆ test_get_proof_start()

◆ test_set_proof_parsing_state()

◆ verifier_init_empty()

Friends And Related Symbol Documentation

◆ bb::extract_transcript_tag

Member Data Documentation

◆ CHALLENGE_BUFFER_SIZE

◆ current_round_data

◆ in_circuit

◆ is_first_challenge

◆ manifest

◆ num_frs_read

◆ num_frs_written

◆ previous_challenge

◆ proof_data

◆ proof_start

◆ reception_phase

◆ round_index

◆ round_number

◆ transcript_index

◆ use_manifest