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Add Joux key agreement example.

This commit is contained in:
Sean Bowe 2016-07-04 09:24:01 -06:00
parent 38f1f7d21d
commit b23de003ee
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2 changed files with 32 additions and 13 deletions
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21
README.md
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@ -36,28 +36,23 @@ extern crate bn;
In a typical Diffie-Hellman key exchange, relying on ECDLP, a three-party key exchange requires two rounds. A single round protocol is possible through the use of a bilinear pairing: given Alice's public key *a*P<sub>1</sub> and Bob's public key *b*P<sub>2</sub>, Carol can compute the shared secret with her private key *c* by *e*(*a*P<sub>1</sub>, *b*P<sub>2</sub>)<sup>c</sup>.
(See `examples/joux.rs` for the full example.)
```rust
extern crate bn;
extern crate rand;
use bn::{Scalar, G1, G2, pairing};
let rng = &mut rand::thread_rng();
// Generate private keys
let alice_sk = Scalar::random(rng);
let bob_sk = Scalar::random(rng);
let carol_sk = Scalar::random(rng);
// Generate public keys in G1 and G2
let (alice_pk1, alice_pk2) = (G1::one() * alice_sk, G2::one() * alice_sk);
let (bob_pk1, bob_pk2) = (G1::one() * bob_sk, G2::one() * bob_sk);
let (carol_pk1, carol_pk2) = (G1::one() * carol_sk, G2::one() * carol_sk);
let (alice_pk1, alice_pk2) = (G1::one() * &alice_sk, G2::one() * &alice_sk);
let (bob_pk1, bob_pk2) = (G1::one() * &bob_sk, G2::one() * &bob_sk);
let (carol_pk1, carol_pk2) = (G1::one() * &carol_sk, G2::one() * &carol_sk);
// Each party computes the shared secret
let alice_dh = pairing(&bob_pk1, &carol_pk2).pow(&alice_sk);
let bob_dh = pairing(&alice_pk2, &carol_pk1).pow(&bob_sk);
let carol_dh = pairing(&alice_pk1, &bob_pk2).pow(&carol_sk);
let alice_dh = pairing(&bob_pk1, &carol_pk2) ^ &alice_sk;
let bob_dh = pairing(&carol_pk1, &alice_pk2) ^ &bob_sk;
let carol_dh = pairing(&alice_pk1, &bob_pk2) ^ &carol_sk;
assert!(alice_dh == bob_dh && bob_dh == carol_dh);
```

24
examples/joux.rs Normal file
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@ -0,0 +1,24 @@
extern crate bn;
extern crate rand;
use bn::{Field, Scalar, G1, G2, pairing};
fn main() {
let rng = &mut rand::thread_rng();
// Generate private keys
let alice_sk = Scalar::random(rng);
let bob_sk = Scalar::random(rng);
let carol_sk = Scalar::random(rng);
// Generate public keys in G1 and G2
let (alice_pk1, alice_pk2) = (G1::one() * &alice_sk, G2::one() * &alice_sk);
let (bob_pk1, bob_pk2) = (G1::one() * &bob_sk, G2::one() * &bob_sk);
let (carol_pk1, carol_pk2) = (G1::one() * &carol_sk, G2::one() * &carol_sk);
// Each party computes the shared secret
let alice_dh = pairing(&bob_pk1, &carol_pk2) ^ &alice_sk;
let bob_dh = pairing(&carol_pk1, &alice_pk2) ^ &bob_sk;
let carol_dh = pairing(&alice_pk1, &bob_pk2) ^ &carol_sk;
assert!(alice_dh == bob_dh && bob_dh == carol_dh);
}