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Module iota::vdf

Constants​

const EInvalidInput: u64 = 0;

Function hash_to_input​

Hash an arbitrary binary message to a class group element to be used as input for vdf_verify.

public fun hash_to_input(message: &vector<u8>): vector<u8>
Implementation
public fun hash_to_input(message: &vector<u8>): vector<u8> {
hash_to_input_internal(message)
}

Function hash_to_input_internal​

The internal functions for hash_to_input.

fun hash_to_input_internal(message: &vector<u8>): vector<u8>
Implementation
native fun hash_to_input_internal(message: &vector<u8>): vector<u8>;

Function vdf_verify​

Verify the output and proof of a VDF with the given number of iterations. The input, output and proof are all class group elements represented by triples (a,b,c) such that b^2 - 4ac = discriminant. The are expected to be encoded as a BCS encoding of a triple of byte arrays, each being the big-endian twos-complement encoding of a, b and c in that order.

This uses Wesolowski's VDF construction over imaginary class groups as described in Wesolowski (2020), 'Efficient Verifiable Delay Functions.', J. Cryptol. 33, and is compatible with the VDF implementation in fastcrypto.

The discriminant for the class group is pre-computed and fixed. See how this was generated in the fastcrypto-vdf crate. The final selection of the discriminant for Mainnet will be computed and announced under a nothing-up-my-sleeve process.

public fun vdf_verify(input: &vector<u8>, output: &vector<u8>, proof: &vector<u8>, iterations: u64): bool
Implementation
public fun vdf_verify(
input: &vector<u8>,
output: &vector<u8>,
proof: &vector<u8>,
iterations: u64,
): bool {
vdf_verify_internal(input, output, proof, iterations)
}

Function vdf_verify_internal​

The internal functions for vdf_verify_internal.

fun vdf_verify_internal(input: &vector<u8>, output: &vector<u8>, proof: &vector<u8>, iterations: u64): bool
Implementation
native fun vdf_verify_internal(
input: &vector<u8>,
output: &vector<u8>,
proof: &vector<u8>,
iterations: u64,
): bool;