Merge branch 'matthias/fix-build' into matthias/make-clippy-happy

Author: matthiasgoergens

README.md

@@ -36,228 +36,7 @@ To import `libspartan` into your Rust project, add the following dependency to `
 spartan = "0.8.0"
 ```
 
-The following example shows how to use `libspartan` to create and verify a SNARK proof.
-Some of our public APIs' style is inspired by the underlying crates we use.
-
-```rust
-extern crate libspartan;
-extern crate merlin;
-use libspartan::{Instance, SNARKGens, SNARK};
-use merlin::Transcript;
-fn main() {
-    // specify the size of an R1CS instance
-    let num_vars = 1024;
-    let num_cons = 1024;
-    let num_inputs = 10;
-    let num_non_zero_entries = 1024;
-
-    // produce public parameters
-    let gens = SNARKGens::new(num_cons, num_vars, num_inputs, num_non_zero_entries);
-
-    // ask the library to produce a synthentic R1CS instance
-    let (inst, vars, inputs) = Instance::produce_synthetic_r1cs(num_cons, num_vars, num_inputs);
-
-    // create a commitment to the R1CS instance
-    let (comm, decomm) = SNARK::encode(&inst, &gens);
-
-    // produce a proof of satisfiability
-    let mut prover_transcript = Transcript::new(b"snark_example");
-    let proof = SNARK::prove(&inst, &comm, &decomm, vars, &inputs, &gens, &mut prover_transcript);
-
-    // verify the proof of satisfiability
-    let mut verifier_transcript = Transcript::new(b"snark_example");
-    assert!(proof
-      .verify(&comm, &inputs, &mut verifier_transcript, &gens)
-      .is_ok());
-    println!("proof verification successful!");
-}
-```
-
-Here is another example to use the NIZK variant of the Spartan proof system:
-
-```rust
-extern crate libspartan;
-extern crate merlin;
-use libspartan::{Instance, NIZKGens, NIZK};
-use merlin::Transcript;
-fn main() {
-    // specify the size of an R1CS instance
-    let num_vars = 1024;
-    let num_cons = 1024;
-    let num_inputs = 10;
-
-    // produce public parameters
-    let gens = NIZKGens::new(num_cons, num_vars, num_inputs);
-
-    // ask the library to produce a synthentic R1CS instance
-    let (inst, vars, inputs) = Instance::produce_synthetic_r1cs(num_cons, num_vars, num_inputs);
-
-    // produce a proof of satisfiability
-    let mut prover_transcript = Transcript::new(b"nizk_example");
-    let proof = NIZK::prove(&inst, vars, &inputs, &gens, &mut prover_transcript);
-
-    // verify the proof of satisfiability
-    let mut verifier_transcript = Transcript::new(b"nizk_example");
-    assert!(proof
-      .verify(&inst, &inputs, &mut verifier_transcript, &gens)
-      .is_ok());
-    println!("proof verification successful!");
-}
-```
-
-Finally, we provide an example that specifies a custom R1CS instance instead of using a synthetic instance
-
-```rust
-#![allow(non_snake_case)]
-extern crate curve25519_dalek;
-extern crate libspartan;
-extern crate merlin;
-use curve25519_dalek::scalar::Scalar;
-use libspartan::{InputsAssignment, Instance, SNARKGens, VarsAssignment, SNARK};
-use merlin::Transcript;
-use rand::rngs::OsRng;
-
-fn main() {
-  // produce a tiny instance
-  let (
-    num_cons,
-    num_vars,
-    num_inputs,
-    num_non_zero_entries,
-    inst,
-    assignment_vars,
-    assignment_inputs,
-  ) = produce_tiny_r1cs();
-
-  // produce public parameters
-  let gens = SNARKGens::new(num_cons, num_vars, num_inputs, num_non_zero_entries);
-
-  // create a commitment to the R1CS instance
-  let (comm, decomm) = SNARK::encode(&inst, &gens);
-
-  // produce a proof of satisfiability
-  let mut prover_transcript = Transcript::new(b"snark_example");
-  let proof = SNARK::prove(
-    &inst,
-    &comm,
-    &decomm,
-    assignment_vars,
-    &assignment_inputs,
-    &gens,
-    &mut prover_transcript,
-  );
-
-  // verify the proof of satisfiability
-  let mut verifier_transcript = Transcript::new(b"snark_example");
-  assert!(proof
-    .verify(&comm, &assignment_inputs, &mut verifier_transcript, &gens)
-    .is_ok());
-  println!("proof verification successful!");
-}
-
-fn produce_tiny_r1cs() -> (
- usize,
- usize,
- usize,
- usize,
- Instance,
- VarsAssignment,
- InputsAssignment,
-) {
-  // We will use the following example, but one could construct any R1CS instance.
-  // Our R1CS instance is three constraints over five variables and two public inputs
-  // (Z0 + Z1) * I0 - Z2 = 0
-  // (Z0 + I1) * Z2 - Z3 = 0
-  // Z4 * 1 - 0 = 0
-
-  // parameters of the R1CS instance rounded to the nearest power of two
-  let num_cons = 4;
-  let num_vars = 5;
-  let num_inputs = 2;
-  let num_non_zero_entries = 5;
-
-  // We will encode the above constraints into three matrices, where
-  // the coefficients in the matrix are in the little-endian byte order
-  let mut A: Vec<(usize, usize, [u8; 32])> = Vec::new();
-  let mut B: Vec<(usize, usize, [u8; 32])> = Vec::new();
-  let mut C: Vec<(usize, usize, [u8; 32])> = Vec::new();
-
-  // The constraint system is defined over a finite field, which in our case is
-  // the scalar field of ristreeto255/curve25519 i.e., p =  2^{252}+27742317777372353535851937790883648493
-  // To construct these matrices, we will use `curve25519-dalek` but one can use any other method.
-
-  // a variable that holds a byte representation of 1
-  let one = Scalar::ONE.to_bytes();
-
-  // R1CS is a set of three sparse matrices A B C, where is a row for every
-  // constraint and a column for every entry in z = (vars, 1, inputs)
-  // An R1CS instance is satisfiable iff:
-  // Az \circ Bz = Cz, where z = (vars, 1, inputs)
-
-  // constraint 0 entries in (A,B,C)
-  // constraint 0 is (Z0 + Z1) * I0 - Z2 = 0.
-  // We set 1 in matrix A for columns that correspond to Z0 and Z1
-  // We set 1 in matrix B for column that corresponds to I0
-  // We set 1 in matrix C for column that corresponds to Z2
-  A.push((0, 0, one));
-  A.push((0, 1, one));
-  B.push((0, num_vars + 1, one));
-  C.push((0, 2, one));
-
-  // constraint 1 entries in (A,B,C)
-  A.push((1, 0, one));
-  A.push((1, num_vars + 2, one));
-  B.push((1, 2, one));
-  C.push((1, 3, one));
-
-  // constraint 3 entries in (A,B,C)
-  A.push((2, 4, one));
-  B.push((2, num_vars, one));
-
-  let inst = Instance::new(num_cons, num_vars, num_inputs, &A, &B, &C).unwrap();
-
-  // compute a satisfying assignment
-  let mut csprng: OsRng = OsRng;
-  let i0 = Scalar::random(&mut csprng);
-  let i1 = Scalar::random(&mut csprng);
-  let z0 = Scalar::random(&mut csprng);
-  let z1 = Scalar::random(&mut csprng);
-  let z2 = (z0 + z1) * i0; // constraint 0
-  let z3 = (z0 + i1) * z2; // constraint 1
-  let z4 = Scalar::ZERO; //constraint 2
-
-  // create a VarsAssignment
-  let mut vars = vec![Scalar::ZERO.to_bytes(); num_vars];
-  vars[0] = z0.to_bytes();
-  vars[1] = z1.to_bytes();
-  vars[2] = z2.to_bytes();
-  vars[3] = z3.to_bytes();
-  vars[4] = z4.to_bytes();
-  let assignment_vars = VarsAssignment::new(&vars).unwrap();
-
-  // create an InputsAssignment
-  let mut inputs = vec![Scalar::ZERO.to_bytes(); num_inputs];
-  inputs[0] = i0.to_bytes();
-  inputs[1] = i1.to_bytes();
-  let assignment_inputs = InputsAssignment::new(&inputs).unwrap();
-
-  // check if the instance we created is satisfiable
-  let res = inst.is_sat(&assignment_vars, &assignment_inputs);
-  assert_eq!(res.unwrap(), true);
-
-  (
-    num_cons,
-    num_vars,
-    num_inputs,
-    num_non_zero_entries,
-    inst,
-    assignment_vars,
-    assignment_inputs,
-  )
- }
-```
-
-For more examples, see [`examples/`](examples) directory in this repo.
+For examples, see [`examples/`](examples) directory in this repo.
 
 ## Building `libspartan`