38 lines
1.1 KiB
Rust
38 lines
1.1 KiB
Rust
|
use pairing::bls12_381::Bls12;
|
||
|
|
use rand::OsRng;
|
||
|
|
use sapling_crypto::{
|
||
|
|
jubjub::{fs::Fs, FixedGenerators, JubjubBls12},
|
||
|
|
redjubjub::{PrivateKey, PublicKey, Signature},
|
||
|
|
};
|
||
|
|
|
||
|
|
/// Create the spendAuthSig for a Sapling SpendDescription.
|
||
|
|
pub fn spend_sig(
|
||
|
|
ask: PrivateKey<Bls12>,
|
||
|
|
ar: Fs,
|
||
|
|
sighash: &[u8; 32],
|
||
|
|
params: &JubjubBls12,
|
||
|
|
) -> Signature {
|
||
|
|
// Initialize secure RNG
|
||
|
|
let mut rng = OsRng::new().expect("should be able to construct RNG");
|
||
|
|
|
||
|
|
// We compute `rsk`...
|
||
|
|
let rsk = ask.randomize(ar);
|
||
|
|
|
||
|
|
// We compute `rk` from there (needed for key prefixing)
|
||
|
|
let rk = PublicKey::from_private(&rsk, FixedGenerators::SpendingKeyGenerator, params);
|
||
|
|
|
||
|
|
// Compute the signature's message for rk/spend_auth_sig
|
||
|
|
let mut data_to_be_signed = [0u8; 64];
|
||
|
|
rk.0.write(&mut data_to_be_signed[0..32])
|
||
|
|
.expect("message buffer should be 32 bytes");
|
||
|
|
(&mut data_to_be_signed[32..64]).copy_from_slice(&sighash[..]);
|
||
|
|
|
||
|
|
// Do the signing
|
||
|
|
rsk.sign(
|
||
|
|
&data_to_be_signed,
|
||
|
|
&mut rng,
|
||
|
|
FixedGenerators::SpendingKeyGenerator,
|
||
|
|
params,
|
||
|
|
)
|
||
|
|
}
|