Documentation
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Overview ¶
Package cometbls provides native bindings for verifying CometBLS Groth16 proofs over BN254 from Gno contracts.
The host-side verifier is a line-for-line Go port of the Rust cometbls-groth16-verifier crate (unionlabs/union: lib/cometbls-groth16-verifier/). Pre-negated verifying-key constants live in constants.go (generated from verifying_key.bin; see the union repo's cmd/gen).
Gno contracts call VerifyZKP declared in cometbls.gno, which encodes the LightHeader using the bespoke fixed-width layout (see EncodedLightHeaderSize) and forwards to X_verifyZKP.
Index ¶
- Constants
- Variables
- func EncodeLightHeader(h LightHeader) []byte
- func PublicInputs(chainID string, trustedValidatorsHash [32]byte, header LightHeader, zkp *ZKP) ([2]fr.Element, error)
- func VerifyZKP(chainID string, trustedValidatorsHash []byte, headerEncoded []byte, ...) error
- func X_verifyZKP(chainID string, trustedValidatorsHash []byte, headerEncoded []byte, zkp []byte) string
- type LightHeader
- type Proof
- type ZKP
Constants ¶
const ( FqSize = 32 G1Size = 2 * FqSize G2Size = 2 * G1Size // ExpectedProofSize is the byte length of a serialized proof: // A(G1) | B(G2) | C(G1) | ProofCommitment(G1) | ProofCommitmentPoK(G1) ExpectedProofSize = G1Size + G2Size + G1Size + G1Size + G1Size // EncodedLightHeaderSize is the byte length of the bespoke LightHeader // encoding accepted by VerifyZKP: // 8 height (BE i64) | 8 seconds (BE i64) | 4 nanos (BE i32) // | 32 validators_hash | 32 next_validators_hash | 32 app_hash EncodedLightHeaderSize = 8 + 8 + 4 + 32 + 32 + 32 )
Field and point sizes (match the Rust crate).
const NbPublicInputs = 2
NbPublicInputs is the number of public inputs to the circuit, excluding the constant term and the Pedersen commitment contribution.
Variables ¶
var ( AlphaG1 bn254.G1Affine BetaNegG2 bn254.G2Affine GammaNegG2 bn254.G2Affine DeltaNegG2 bn254.G2Affine PedersenG bn254.G2Affine PedersenGRootSigmaNeg bn254.G2Affine GammaAbcG1 [3]bn254.G1Affine )
Pre-negated Groth16 verifying-key constants extracted from verifying_key.bin. BetaNegG2, GammaNegG2, DeltaNegG2 and PedersenGRootSigmaNeg are stored pre-negated so pairing checks can be evaluated as a single product equal to 1 (matching the Rust cometbls-groth16-verifier).
var ( ErrInvalidPublicInput = errors.New("invalid public input") ErrInvalidPoint = errors.New("invalid point") ErrInvalidProof = errors.New("invalid proof") ErrInvalidPok = errors.New("invalid pok") ErrInvalidCommitment = errors.New("invalid commitment") ErrInvalidRawProof = errors.New("invalid raw proof") ErrInvalidHeight = errors.New("invalid height") ErrInvalidTimestamp = errors.New("invalid timestamp") ErrInvalidHeaderLen = errors.New("invalid header encoding length") ErrInvalidChainIDLen = errors.New("chain id must be at most 31 bytes") )
Sentinel errors mirroring the Rust `Error` enum. Tests compare against these by identity using errors.Is.
Functions ¶
func EncodeLightHeader ¶
func EncodeLightHeader(h LightHeader) []byte
EncodeLightHeader produces the bespoke fixed-width encoding accepted by VerifyZKP. A matching encoder is provided gno-side in cometbls.gno.
func PublicInputs ¶
func PublicInputs(chainID string, trustedValidatorsHash [32]byte, header LightHeader, zkp *ZKP) ([2]fr.Element, error)
PublicInputs computes the two scalar public inputs consumed by the circuit: the SHA-256-derived inputs hash (top byte zeroed to fit in F_r) and the commitment hash.
func VerifyZKP ¶
func VerifyZKP(chainID string, trustedValidatorsHash []byte, headerEncoded []byte, zkpBytes []byte) error
VerifyZKP verifies a CometBLS Groth16 proof. The header is accepted in the bespoke fixed-width encoding produced by EncodeLightHeader (see EncodedLightHeaderSize for the layout).
Returns nil on success or one of the sentinel errors on failure.
func X_verifyZKP ¶
func X_verifyZKP(chainID string, trustedValidatorsHash []byte, headerEncoded []byte, zkp []byte) string
X_verifyZKP is the host-side native binding for the `verifyZKP` function declared in cometbls.gno. It returns an empty string on successful proof verification and a non-empty error message otherwise — gno cannot currently return a Go `error` across the native ABI, so the gno wrapper converts the string back into an error value.
`headerEncoded` must be exactly EncodedLightHeaderSize bytes (116); see EncodeLightHeader in cometbls.gno for the canonical encoder.
Types ¶
type LightHeader ¶
type LightHeader struct {
Height int64
TimeSeconds int64
TimeNanos int32
ValidatorsHash [32]byte
NextValidatorsHash [32]byte
AppHash [32]byte
}
LightHeader matches cometbls-light-client-types::LightHeader.
func DecodeLightHeader ¶
func DecodeLightHeader(buf []byte) (LightHeader, error)
DecodeLightHeader parses the bespoke encoding, validating bounds.
Source Files