Crate bellpepper_core 

bellpepper is a crate for building zk-SNARK circuits. It provides circuit traits and and primitive structures, as well as basic gadget implementations such as booleans and number abstractions.

Example circuit

Say we want to write a circuit that proves we know the preimage to some hash computed using SHA-256d (calling SHA-256 twice). The preimage must have a fixed length known in advance (because the circuit parameters will depend on it), but can otherwise have any value. We take the following strategy:

• Witness each bit of the preimage.
• Compute hash = SHA-256d(preimage) inside the circuit.
• Expose hash as a public input using multiscalar packing.

Modules

boolean

Gadgets for allocating bits in the circuit and performing boolean logic.

num

Gadgets representing numbers in the scalar field of the underlying curve.

test_cs

Structs

LinearCombination

This represents a linear combination of some variables, with coefficients in the scalar field of a pairing-friendly elliptic curve group.

Namespace

This is a “namespaced” constraint system which borrows a constraint system (pushing a namespace context) and, when dropped, pops out of the namespace context.

Variable

Represents a variable in our constraint system.

Enums

Delta

Index

Represents the index of either an input variable or auxiliary variable.

SynthesisError

This is an error that could occur during circuit synthesis contexts, such as CRS generation, proving or verification.

Constants

BELLPEPPER_VERSION

Traits

Circuit

Computations are expressed in terms of arithmetic circuits, in particular rank-1 quadratic constraint systems. The Circuit trait represents a circuit that can be synthesized. The synthesize method is called during CRS generation and during proving.

Comparable

ConstraintSystem

Represents a constraint system which can have new variables allocated and constrains between them formed.

Type Aliases

Constraint