Files
darkfi/proof/burn.zk
parazyd 6a024ab801 zkas: Add a field definition on top of the circuit file.
Currently unused, but will probably be expanded to define proofs over
different fields.
2023-08-14 17:09:18 +02:00

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k = 13;
field = "pallas";
constant "Burn" {
EcFixedPointShort VALUE_COMMIT_VALUE,
EcFixedPoint VALUE_COMMIT_RANDOM,
EcFixedPointBase NULLIFIER_K,
}
witness "Burn" {
Base secret,
Base serial,
Base value,
Base token,
Scalar value_blind,
Scalar token_blind,
Uint32 leaf_pos,
MerklePath path,
Base signature_secret,
}
circuit "Burn" {
# Poseidon hash of the nullifier
nullifier = poseidon_hash(secret, serial);
constrain_instance(nullifier);
# Pedersen commitment for coin's value
vcv = ec_mul_short(value, VALUE_COMMIT_VALUE);
vcr = ec_mul(value_blind, VALUE_COMMIT_RANDOM);
value_commit = ec_add(vcv, vcr);
# Since value_commit is a curve point, we fetch its coordinates
# and constrain them:
value_commit_x = ec_get_x(value_commit);
value_commit_y = ec_get_y(value_commit);
constrain_instance(value_commit_x);
constrain_instance(value_commit_y);
# Pedersen commitment for coin's token ID
tcv = ec_mul_base(token, NULLIFIER_K);
tcr = ec_mul(token_blind, VALUE_COMMIT_RANDOM);
token_commit = ec_add(tcv, tcr);
# Since token_commit is also a curve point, we'll do the same
# coordinate dance:
token_commit_x = ec_get_x(token_commit);
token_commit_y = ec_get_y(token_commit);
constrain_instance(token_commit_x);
constrain_instance(token_commit_y);
# Coin hash
pub = ec_mul_base(secret, NULLIFIER_K);
pub_x = ec_get_x(pub);
pub_y = ec_get_y(pub);
C = poseidon_hash(pub_x, pub_y, value, token, serial);
# Merkle root
root = merkle_root(leaf_pos, path, C);
constrain_instance(root);
# Finally, we derive a public key for the signature and
# constrain its coordinates:
signature_public = ec_mul_base(signature_secret, NULLIFIER_K);
signature_x = ec_get_x(signature_public);
signature_y = ec_get_y(signature_public);
constrain_instance(signature_x);
constrain_instance(signature_y);
# At this point we've enforced all of our public inputs.
}