Compresses Chonk proofs from vector<fr> to compact byte representations. More...

#include <proof_compression.hpp>

Static Public Member Functions
static size_t	compressed_element_count (size_t mega_num_public_inputs=0)
	Count the total compressed elements for a Chonk proof. Each element (scalar or commitment, either curve) compresses to exactly 32 bytes.

static size_t	compressed_mega_num_public_inputs (size_t compressed_bytes)
	Derive mega_num_public_inputs from compressed proof size.

static std::vector< uint8_t >	compress_chonk_proof (const ChonkProof &proof)

static ChonkProof	decompress_chonk_proof (const std::vector< uint8_t > &compressed, size_t mega_num_public_inputs)

Private Types
using	Fr = curve::BN254::ScalarField

using	Fq = curve::BN254::BaseField

Static Private Member Functions
template<typename Field >
static bool	y_is_negative (const Field &y)
	True if y is in the "upper half" of its field, used for point compression sign bit.

static void	write_u256 (std::vector< uint8_t > &out, const uint256_t &val)

static uint256_t	read_u256 (const std::vector< uint8_t > &data, size_t &pos)

static Fq	reconstruct_fq (const Fr &lo, const Fr &hi)

static std::pair< Fr, Fr >	split_fq (const Fq &val)

template<typename ScalarFn , typename CommitmentFn >
static void	walk_mega_zk_proof (ScalarFn &&process_scalar, CommitmentFn &&process_commitment, size_t num_public_inputs)
	Walk a MegaZK proof (BN254, ZK sumcheck).

template<typename ScalarFn , typename CommitmentFn >
static void	walk_merge_proof (ScalarFn &&process_scalar, CommitmentFn &&process_commitment)
	Walk a Merge proof (42 Fr, all BN254).

template<typename ScalarFn , typename CommitmentFn >
static void	walk_eccvm_proof (ScalarFn &&process_scalar, CommitmentFn &&process_commitment)
	Walk an ECCVM proof (all Grumpkin).

template<typename ScalarFn , typename CommitmentFn >
static void	walk_ipa_proof (ScalarFn &&process_scalar, CommitmentFn &&process_commitment)
	Walk an IPA proof (64 Fr, all Grumpkin).

template<typename ScalarFn , typename CommitmentFn >
static void	walk_translator_proof (ScalarFn &&process_scalar, CommitmentFn &&process_commitment)
	Walk a Translator proof (all BN254).

template<typename BN254ScalarFn , typename BN254CommFn , typename GrumpkinScalarFn , typename GrumpkinCommFn >
static void	walk_chonk_proof (BN254ScalarFn &&bn254_scalar, BN254CommFn &&bn254_comm, GrumpkinScalarFn &&grumpkin_scalar, GrumpkinCommFn &&grumpkin_comm, size_t mega_num_public_inputs)
	Walk a full Chonk proof (5 sub-proofs across two curves).

Static Private Attributes
static constexpr uint256_t	SIGN_BIT_MASK = uint256_t(1) << 255

static constexpr uint64_t	NUM_LIMB_BITS = 68

static constexpr uint64_t	FQ_SPLIT_BITS = NUM_LIMB_BITS * 2

static constexpr size_t	BN254_FRS_PER_SCALAR = 1

static constexpr size_t	BN254_FRS_PER_COMM = 4

static constexpr size_t	GRUMPKIN_FRS_PER_SCALAR = 2

static constexpr size_t	GRUMPKIN_FRS_PER_COMM = 2

static constexpr size_t	EXPECTED_MEGA_ZK_FRS

static constexpr size_t	EXPECTED_MERGE_FRS

static constexpr size_t	EXPECTED_ECCVM_FRS

static constexpr size_t	EXPECTED_IPA_FRS

static constexpr size_t	EXPECTED_TRANSLATOR_FRS

Detailed Description

Compresses Chonk proofs from vector<fr> to compact byte representations.

Compression techniques:

Point compression: store only x-coordinate + sign bit (instead of x and y)
Fq-as-u256: store each Fq coordinate as 32 bytes (instead of 2 Fr for lo/hi split)
Fr-as-u256: store each Fr scalar as 32 bytes (uniform encoding)

Every element compresses to exactly 32 bytes regardless of type:

BN254 commitment (4 Fr → 32 bytes): point compression on Fq coordinates
BN254 scalar (1 Fr → 32 bytes): direct u256 encoding
Grumpkin commitment (2 Fr → 32 bytes): point compression on Fr coordinates
Grumpkin scalar (2 Fr → 32 bytes): reconstruct Fq, write as u256

Definition at line 32 of file proof_compression.hpp.

Member Typedef Documentation

◆ Fq

using bb::ProofCompressor::Fq = curve::BN254::BaseField

private

Definition at line 34 of file proof_compression.hpp.

◆ Fr

using bb::ProofCompressor::Fr = curve::BN254::ScalarField

private

Definition at line 33 of file proof_compression.hpp.

Member Function Documentation

◆ compress_chonk_proof()

static std::vector< uint8_t > bb::ProofCompressor::compress_chonk_proof ( const ChonkProof & proof )

inlinestatic

Definition at line 430 of file proof_compression.hpp.

◆ compressed_element_count()

static size_t bb::ProofCompressor::compressed_element_count ( size_t mega_num_public_inputs = 0 )

inlinestatic

Count the total compressed elements for a Chonk proof. Each element (scalar or commitment, either curve) compresses to exactly 32 bytes.

Definition at line 405 of file proof_compression.hpp.

◆ compressed_mega_num_public_inputs()

static size_t bb::ProofCompressor::compressed_mega_num_public_inputs ( size_t compressed_bytes )

inlinestatic

Derive mega_num_public_inputs from compressed proof size.

Parameters

compressed_bytes Total size of the compressed proof in bytes.

Definition at line 417 of file proof_compression.hpp.

◆ decompress_chonk_proof()

static ChonkProof bb::ProofCompressor::decompress_chonk_proof	(	const std::vector< uint8_t > &	compressed,
		size_t	mega_num_public_inputs
	)

inlinestatic

Definition at line 493 of file proof_compression.hpp.

◆ read_u256()

static uint256_t bb::ProofCompressor::read_u256	(	const std::vector< uint8_t > &	data,
		size_t &	pos
	)

inlinestaticprivate

Definition at line 59 of file proof_compression.hpp.

◆ reconstruct_fq()

static Fq bb::ProofCompressor::reconstruct_fq	(	const Fr &	lo,
		const Fr &	hi
	)

inlinestaticprivate

Definition at line 68 of file proof_compression.hpp.

◆ split_fq()

static std::pair< Fr, Fr > bb::ProofCompressor::split_fq ( const Fq & val )

inlinestaticprivate

Definition at line 73 of file proof_compression.hpp.

◆ walk_chonk_proof()

template<typename BN254ScalarFn , typename BN254CommFn , typename GrumpkinScalarFn , typename GrumpkinCommFn >

static void bb::ProofCompressor::walk_chonk_proof	(	BN254ScalarFn &&	bn254_scalar,
		BN254CommFn &&	bn254_comm,
		GrumpkinScalarFn &&	grumpkin_scalar,
		GrumpkinCommFn &&	grumpkin_comm,
		size_t	mega_num_public_inputs
	)

inlinestaticprivate

Walk a full Chonk proof (5 sub-proofs across two curves).

Definition at line 304 of file proof_compression.hpp.

◆ walk_eccvm_proof()

template<typename ScalarFn , typename CommitmentFn >

static void bb::ProofCompressor::walk_eccvm_proof	(	ScalarFn &&	process_scalar,
		CommitmentFn &&	process_commitment
	)

inlinestaticprivate

Walk an ECCVM proof (all Grumpkin).

Layout from ECCVMFlavor::PROOF_LENGTH formula and ECCVM prover code. Grumpkin RoundUnivariateHandler commits to each round univariate and sends 2 evaluations (at 0 and 1), interleaved per round.

Definition at line 168 of file proof_compression.hpp.

◆ walk_ipa_proof()

template<typename ScalarFn , typename CommitmentFn >

static void bb::ProofCompressor::walk_ipa_proof	(	ScalarFn &&	process_scalar,
		CommitmentFn &&	process_commitment
	)

inlinestaticprivate

Walk an IPA proof (64 Fr, all Grumpkin).

IPA_PROOF_LENGTH = 4 * CONST_ECCVM_LOG_N + 4

Definition at line 236 of file proof_compression.hpp.

◆ walk_mega_zk_proof()

template<typename ScalarFn , typename CommitmentFn >

static void bb::ProofCompressor::walk_mega_zk_proof	(	ScalarFn &&	process_scalar,
		CommitmentFn &&	process_commitment,
		size_t	num_public_inputs
	)

inlinestaticprivate

Walk a MegaZK proof (BN254, ZK sumcheck).

Layout from MegaZKStructuredProofBase and sumcheck prover code.

Definition at line 89 of file proof_compression.hpp.

◆ walk_merge_proof()

template<typename ScalarFn , typename CommitmentFn >

static void bb::ProofCompressor::walk_merge_proof	(	ScalarFn &&	process_scalar,
		CommitmentFn &&	process_commitment
	)

inlinestaticprivate

Walk a Merge proof (42 Fr, all BN254).

Layout from MergeProver::construct_proof.

Definition at line 142 of file proof_compression.hpp.

◆ walk_translator_proof()

template<typename ScalarFn , typename CommitmentFn >

static void bb::ProofCompressor::walk_translator_proof	(	ScalarFn &&	process_scalar,
		CommitmentFn &&	process_commitment
	)

inlinestaticprivate

Walk a Translator proof (all BN254).

Layout from TranslatorFlavor::PROOF_LENGTH formula.

Definition at line 254 of file proof_compression.hpp.

◆ write_u256()

static void bb::ProofCompressor::write_u256	(	std::vector< uint8_t > &	out,
		const uint256_t &	val
	)

inlinestaticprivate

Definition at line 52 of file proof_compression.hpp.

◆ y_is_negative()

template<typename Field >

static bool bb::ProofCompressor::y_is_negative ( const Field & y )

inlinestaticprivate

True if y is in the "upper half" of its field, used for point compression sign bit.

Definition at line 43 of file proof_compression.hpp.

Member Data Documentation

◆ BN254_FRS_PER_COMM

constexpr size_t bb::ProofCompressor::BN254_FRS_PER_COMM = 4

staticconstexprprivate

Definition at line 325 of file proof_compression.hpp.

◆ BN254_FRS_PER_SCALAR

constexpr size_t bb::ProofCompressor::BN254_FRS_PER_SCALAR = 1

staticconstexprprivate

Definition at line 324 of file proof_compression.hpp.

◆ EXPECTED_ECCVM_FRS

constexpr size_t bb::ProofCompressor::EXPECTED_ECCVM_FRS

staticconstexprprivate

Initial value:

=
        (ECCVMFlavor::NUM_WITNESS_ENTITIES + ECCVMFlavor::NUM_MASKING_POLYNOMIALS) * GRUMPKIN_FRS_PER_COMM + 
        1 * GRUMPKIN_FRS_PER_COMM +                                                                         
        1 * GRUMPKIN_FRS_PER_SCALAR +                                                                       
        CONST_ECCVM_LOG_N * GRUMPKIN_FRS_PER_COMM +                                                         
        2 * CONST_ECCVM_LOG_N * GRUMPKIN_FRS_PER_SCALAR +                                                   
        ECCVMFlavor::NUM_ALL_ENTITIES * GRUMPKIN_FRS_PER_SCALAR +                                            
        1 * GRUMPKIN_FRS_PER_SCALAR +                                                                       
        2 * GRUMPKIN_FRS_PER_COMM +                                                                         
        (CONST_ECCVM_LOG_N - 1) * GRUMPKIN_FRS_PER_COMM +                                                  
        CONST_ECCVM_LOG_N * GRUMPKIN_FRS_PER_SCALAR +                                                       
        NUM_SMALL_IPA_EVALUATIONS * GRUMPKIN_FRS_PER_SCALAR +                                               
        1 * GRUMPKIN_FRS_PER_COMM +                                                                         
        1 * GRUMPKIN_FRS_PER_COMM +                                                                         
        NUM_TRANSLATION_EVALUATIONS * GRUMPKIN_FRS_PER_SCALAR +                                             
        1 * GRUMPKIN_FRS_PER_SCALAR +                                                                       
        2 * GRUMPKIN_FRS_PER_COMM +                                                                         
        NUM_SMALL_IPA_EVALUATIONS * GRUMPKIN_FRS_PER_SCALAR +                                               
        1 * GRUMPKIN_FRS_PER_COMM

Definition at line 354 of file proof_compression.hpp.

◆ EXPECTED_IPA_FRS

constexpr size_t bb::ProofCompressor::EXPECTED_IPA_FRS

staticconstexprprivate

Initial value:

=
        2 * CONST_ECCVM_LOG_N * GRUMPKIN_FRS_PER_COMM + 
        1 * GRUMPKIN_FRS_PER_COMM +                     
        1 * GRUMPKIN_FRS_PER_SCALAR

Definition at line 376 of file proof_compression.hpp.

◆ EXPECTED_MEGA_ZK_FRS

constexpr size_t bb::ProofCompressor::EXPECTED_MEGA_ZK_FRS

staticconstexprprivate

Initial value:

=
        MegaZKFlavor::NUM_WITNESS_ENTITIES * BN254_FRS_PER_COMM +                                           
        1 * BN254_FRS_PER_COMM +                                                                            
        1 * BN254_FRS_PER_SCALAR +                                                                          
        MegaZKFlavor::VIRTUAL_LOG_N * MegaZKFlavor::BATCHED_RELATION_PARTIAL_LENGTH * BN254_FRS_PER_SCALAR +
        MegaZKFlavor::NUM_ALL_ENTITIES * BN254_FRS_PER_SCALAR +                                             
        1 * BN254_FRS_PER_SCALAR +                                                                          
        2 * BN254_FRS_PER_COMM +                                                                            
        (MegaZKFlavor::VIRTUAL_LOG_N - 1) * BN254_FRS_PER_COMM +                                           
        MegaZKFlavor::VIRTUAL_LOG_N * BN254_FRS_PER_SCALAR +                                                
        NUM_SMALL_IPA_EVALUATIONS * BN254_FRS_PER_SCALAR +                                                  
        2 * BN254_FRS_PER_COMM

Definition at line 331 of file proof_compression.hpp.

◆ EXPECTED_MERGE_FRS

constexpr size_t bb::ProofCompressor::EXPECTED_MERGE_FRS

staticconstexprprivate

Initial value:

=
        1 * BN254_FRS_PER_SCALAR +  
        5 * BN254_FRS_PER_COMM +    
        13 * BN254_FRS_PER_SCALAR + 
        2 * BN254_FRS_PER_COMM

Definition at line 346 of file proof_compression.hpp.

◆ EXPECTED_TRANSLATOR_FRS

constexpr size_t bb::ProofCompressor::EXPECTED_TRANSLATOR_FRS

staticconstexprprivate

Initial value:

=
        1 * BN254_FRS_PER_COMM +                                                                                   
        TranslatorFlavor::NUM_COMMITMENTS_IN_PROOF * BN254_FRS_PER_COMM +                                          
        1 * BN254_FRS_PER_COMM +                                                                                   
        1 * BN254_FRS_PER_COMM +                                                                                   
        1 * BN254_FRS_PER_SCALAR +                                                                                 
        TranslatorFlavor::CONST_TRANSLATOR_LOG_N * TranslatorFlavor::BATCHED_RELATION_PARTIAL_LENGTH * BN254_FRS_PER_SCALAR + 
        TranslatorFlavor::NUM_SENT_EVALUATIONS * BN254_FRS_PER_SCALAR +                                            
        1 * BN254_FRS_PER_SCALAR +                                                                                 
        2 * BN254_FRS_PER_COMM +                                                                                   
        (TranslatorFlavor::CONST_TRANSLATOR_LOG_N - 1) * BN254_FRS_PER_COMM +                                     
        TranslatorFlavor::CONST_TRANSLATOR_LOG_N * BN254_FRS_PER_SCALAR +                                          
        NUM_SMALL_IPA_EVALUATIONS * BN254_FRS_PER_SCALAR +                                                         
        2 * BN254_FRS_PER_COMM

Definition at line 383 of file proof_compression.hpp.

◆ FQ_SPLIT_BITS

constexpr uint64_t bb::ProofCompressor::FQ_SPLIT_BITS = NUM_LIMB_BITS * 2

staticconstexprprivate

Definition at line 40 of file proof_compression.hpp.

◆ GRUMPKIN_FRS_PER_COMM

constexpr size_t bb::ProofCompressor::GRUMPKIN_FRS_PER_COMM = 2

staticconstexprprivate

Definition at line 327 of file proof_compression.hpp.

◆ GRUMPKIN_FRS_PER_SCALAR

constexpr size_t bb::ProofCompressor::GRUMPKIN_FRS_PER_SCALAR = 2

staticconstexprprivate

Definition at line 326 of file proof_compression.hpp.

◆ NUM_LIMB_BITS

constexpr uint64_t bb::ProofCompressor::NUM_LIMB_BITS = 68

staticconstexprprivate

Definition at line 39 of file proof_compression.hpp.

◆ SIGN_BIT_MASK

constexpr uint256_t bb::ProofCompressor::SIGN_BIT_MASK = uint256_t(1) << 255

staticconstexprprivate

Definition at line 36 of file proof_compression.hpp.

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

src/barretenberg/chonk/proof_compression.hpp

Static Public Member Functions

Private Types

Static Private Member Functions

Static Private Attributes

Detailed Description

Member Typedef Documentation

◆ Fq

◆ Fr

Member Function Documentation

◆ compress_chonk_proof()

◆ compressed_element_count()

◆ compressed_mega_num_public_inputs()

◆ decompress_chonk_proof()

◆ read_u256()

◆ reconstruct_fq()

◆ split_fq()

◆ walk_chonk_proof()

◆ walk_eccvm_proof()

◆ walk_ipa_proof()

◆ walk_mega_zk_proof()

◆ walk_merge_proof()

◆ walk_translator_proof()

◆ write_u256()

◆ y_is_negative()

Member Data Documentation

◆ BN254_FRS_PER_COMM

◆ BN254_FRS_PER_SCALAR

◆ EXPECTED_ECCVM_FRS

◆ EXPECTED_IPA_FRS

◆ EXPECTED_MEGA_ZK_FRS

◆ EXPECTED_MERGE_FRS

◆ EXPECTED_TRANSLATOR_FRS

◆ FQ_SPLIT_BITS

◆ GRUMPKIN_FRS_PER_COMM

◆ GRUMPKIN_FRS_PER_SCALAR

◆ NUM_LIMB_BITS

◆ SIGN_BIT_MASK