Module bbs_plus::setup

Keys and setup parameters

Examples

Creating signature parameters and keypair:

use ark_bls12_381::Bls12_381;
use blake2::Blake2b512;
use bbs_plus::setup::{SignatureParamsG1, SignatureParamsG2, KeypairG1, KeypairG2, PublicKeyG2, SignatureParams23G1};

// For BBS+ signatures

let params_g1 = SignatureParamsG1::<Bls12_381>::generate_using_rng(&mut rng, 5);
let params_g2 = SignatureParamsG2::<Bls12_381>::generate_using_rng(&mut rng, 5);
let params_g1_1 = SignatureParamsG1::<Bls12_381>::new::<Blake2b512>(&[1, 2, 3, 4], 5);
let params_g2_1 = SignatureParamsG2::<Bls12_381>::new::<Blake2b512>(&[1, 2, 3, 4], 5);

let keypair_g2 = KeypairG2::<Bls12_381>::generate_using_rng(&mut rng, &params_g1);
let keypair_g1 = KeypairG1::<Bls12_381>::generate_using_rng(&mut rng, &params_g2);

// Generate keypair using a secret `seed`. The same seed will return same keypair. The seed
// is hashed (along with other things) using the given hash function, the example below use Blake2b512
// let seed: &[u8] = <Some secret seed>
let keypair_g21 = KeypairG2::<Bls12_381>::generate_using_seed::<Blake2b512>(seed, &params_g1);

// public and secret key from `Keypair`
let sk = keypair_g2.secret_key;
let pk = keypair_g2.public_key;

// Another way to generate keypair is
let sk = SecretKey::generate_using_seed::<Blake2b512>(&seed);
let pk = PublicKeyG2::public_key_from_secret_key(&sk, &params_g1);
KeypairG2 {secret_key: sk, public_key: pk}

// For BBS signatures

// For BBS, sig params are `SignatureParams23G1` but public key is `PublicKeyG2`
let params = SignatureParams23G1::<Bls12_381>::generate_using_rng(&mut rng, 5);
let params_1 = SignatureParams23G1::<Bls12_381>::new::<Blake2b512>(&[1, 2, 3, 4], 5);

let keypair = KeypairG2::<Bls12_381>::generate_using_rng_and_bbs23_params(&mut rng, &params);
let keypair_1 = KeypairG2::<Bls12_381>::generate_using_seed_and_bbs23_params::<Blake2b512>(seed, &params);

let pk = PublicKeyG2::generate_using_secret_key_and_bbs23_params(&sk, &params);
KeypairG2 {secret_key: sk, public_key: pk}

Structs

• KeypairG1
• KeypairG2
• PreparedPublicKeyG2
• PreparedSignatureParams23G1
  Signature params for BBS signatures with G2 element prepared for pairing
• PreparedSignatureParamsG1
• PublicKeyG1
  Public key of the signer. The signer can use the same public key with different signature parameters to sign different multi-messages, provided that parameter g2 is consistent with the ‘g2’ used to generate the public key.
• PublicKeyG2
  Public key of the signer. The signer can use the same public key with different signature parameters to sign different multi-messages, provided that parameter g2 is consistent with the ‘g2’ used to generate the public key.
• SecretKey
  Secret key used by the signer to sign messages
• SignatureParams23G1
  BBS signature params used for signing, verifying and proving knowledge of signature.
• SignatureParamsG1
  BBS+ signature params used while signing and verifying. Also used when proving knowledge of signature. Every signer can create his own params but several signers can share the same parameters if signing messages of the same size and still have their own public keys. Size of parameters is proportional to the number of messages
• SignatureParamsG2
  BBS+ signature params used while signing and verifying. Also used when proving knowledge of signature. Every signer can create his own params but several signers can share the same parameters if signing messages of the same size and still have their own public keys. Size of parameters is proportional to the number of messages