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Cryptographic Functions

SHA-256​

#include <ligetron/sha2.h>

// Compute SHA-256 hash
// Returns number of bytes written (32)
uint32_t ligetron_sha2_256(unsigned char* out, 
                            const unsigned char* in, 
                            uint32_t len);

Rust Example:

use ligetron::sha2::*;

let input = b"Hello, world!";
let hash = sha256(input);

Poseidon Hash​

#include <ligetron/poseidon.h>

using namespace ligetron;

// Poseidon with t=5 (4 inputs -> 1 output)
poseidon_context<poseidon_permx5_254bit_5> ctx;

// Initialize constants
poseidon_context<poseidon_permx5_254bit_5>::global_init();

// Reset state
ctx.reset();

// Absorb inputs
bn254fr_class input1, input2;
ctx.digest_update(input1);
ctx.digest_update(input2);

// Finalize and get hash
ctx.digest_final();
bn254fr_class hash_output = ctx.state[0];

Poseidon Variants:

  • poseidon_permx5_254bit_3: t=3 (2 inputs)
  • poseidon_permx5_254bit_5: t=5 (4 inputs)

Rust Example:

use ligetron::poseidon::*;

// Poseidon hash (2 inputs -> 1 output)
let hash = poseidon2to1(&input1, &input2);

// Poseidon hash (4 inputs -> 1 output)
let hash = poseidon4to1(&input1, &input2, &input3, &input4);

Poseidon2 Hash​

#include <ligetron/poseidon2.h>

// Similar to Poseidon, but optimized for t=2

Rust Example:

use ligetron::poseidon2::*;

// Poseidon2 for byte arrays
let input = b"Hello, world!";
let hash = poseidon2_bytes(input);

// Batch hashing
let hashes = poseidon2_bytes_batch(&inputs);

EdDSA Signatures​

#include <ligetron/eddsa.h>
#include <ligetron/babyjubjub.h>

// Verify EdDSA signature
bool verify_eddsa(const uint8_t* message, size_t msg_len,
                  const uint8_t* signature, 
                  const uint8_t* public_key);

Rust Example:

use ligetron::eddsa::*;
use ligetron::babyjubjub::*;

// Verify signature
let is_valid = eddsa_verify(&message, &signature, &public_key);
assert_one(is_valid);

Baby Jubjub Curve​

The Baby Jubjub curve is a twisted Edwards curve optimized for zero-knowledge circuits:

#include <ligetron/babyjubjub.h>

// Point operations, scalar multiplication, etc.