You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
96 lines
2.9 KiB
96 lines
2.9 KiB
8 years ago
|
# JNI for mcl (experimental)
|
||
|
|
This library provides functionality to compute the optimal ate pairing
|
||
|
|
over Barreto-Naehrig (BN) curves.
|
||
|
|
|
||
|
|
# Initialization
|
||
|
|
Load the library `mcl_bn256`.
|
||
|
|
```
|
||
|
|
import com.herumi.mcl.*;
|
||
|
|
|
||
|
|
System.loadLibrary("mcl_bn256");
|
||
|
|
```
|
||
|
|
|
||
|
|
# Classes
|
||
|
|
* `G1` ; The cyclic group instantiated as E(Fp)[r] where where r = p + 1 - t.
|
||
|
|
* `G2` ; The cyclic group instantiated as the inverse image of E'(Fp^2)[r].
|
||
|
|
* `GT` ; The cyclic group in the image of the optimal ate pairing.
|
||
|
|
* `e : G2 x G1 -> GT`
|
||
|
|
* `Fr` ; The finite field with characteristic r.
|
||
|
|
|
||
|
|
# Methods and Functions
|
||
|
|
## Fr
|
||
|
|
* `Fr::setInt(int x)` ; set by x
|
||
|
|
* `Fr::setStr(String str)` ; set by str such as "123", "0xfff", etc.
|
||
|
|
* `Fr::setRand()` ; randomly set
|
||
|
|
* `Bn256.neg(Fr y, Fr x)` ; `y = -x`
|
||
|
|
* `Bn256.add(Fr z, Fr x, Fr y)` ; `z = x + y`
|
||
|
|
* `Bn256.sub(Fr z, Fr x, Fr y)` ; `z = x - y`
|
||
|
|
* `Bn256.mul(Fr z, Fr x, Fr y)` ; `z = x * y`
|
||
|
|
* `Bn256.div(Fr z, Fr x, Fr y)` ; `z = x / y`
|
||
|
|
|
||
|
|
## G1
|
||
|
|
|
||
|
|
* `G1::set(String x, String y)` ; set by (x, y)
|
||
|
|
* `G1::hashAndMapToG1(String m)` ; take SHA-256 of m and map it to an element of G1
|
||
|
|
* `G1::setStr(String str)` ; set by the result of `toString()` method
|
||
|
|
* `Bn256.neg(G1 y, G1 x)` ; `y = -x`
|
||
|
|
* `Bn256.dbl(G1 y, G1 x)` ; `y = 2x`
|
||
|
|
* `Bn256.add(G1 z, G1 x, G1 y)` ; `z = x + y`
|
||
|
|
* `Bn256.sub(G1 z, G1 x, G1 y)` ; `z = x - y`
|
||
|
|
* `Bn256.mul(G1 z, G1 x, Fr y)` ; `z = x * y`
|
||
|
|
|
||
|
|
## G2
|
||
|
|
|
||
|
|
* `G2::set(String xa, String xb, String ya, String yb)` ; set by ((xa, xb), (ya, yb))
|
||
|
|
* `G2::setStr(String str)` ; set by the result of `toString()` method
|
||
|
|
* `Bn256.neg(G2 y, G2 x)` ; `y = -x`
|
||
|
|
* `Bn256.dbl(G2 y, G2 x)` ; `y = 2x`
|
||
|
|
* `Bn256.add(G2 z, G2 x, G2 y)` ; `z = x + y`
|
||
|
|
* `Bn256.sub(G2 z, G2 x, G2 y)` ; `z = x - y`
|
||
|
|
* `Bn256.mul(G2 z, G2 x, Fr y)` ; `z = x * y`
|
||
|
|
|
||
|
|
## GT
|
||
|
|
|
||
|
|
* `GT::setStr(String str)` ; set by the result of `toString()` method
|
||
|
|
* `Bn256.mul(GT z, GT x, GT y)` ; `z = x * y`
|
||
|
|
* `Bn256.pow(GT z, GT x, Fr y)` ; `z = x ^ y`
|
||
|
|
|
||
|
|
## pairing
|
||
|
|
* `Bn256.pairing(GT e, G2 Q, G1 P)` ; e = e(Q, P)
|
||
|
|
|
||
|
|
# BLS signature sample
|
||
|
|
```
|
||
|
|
String xa = "12723517038133731887338407189719511622662176727675373276651903807414909099441";
|
||
|
|
String xb = "4168783608814932154536427934509895782246573715297911553964171371032945126671";
|
||
|
|
String ya = "13891744915211034074451795021214165905772212241412891944830863846330766296736";
|
||
|
|
String yb = "7937318970632701341203597196594272556916396164729705624521405069090520231616";
|
||
|
|
|
||
|
|
G2 Q = new G2(xa, xb, ya, yb); // fixed point of G2
|
||
|
|
|
||
|
|
Fr s = new Fr();
|
||
|
|
s.setRand(); // secret key
|
||
|
|
G2 pub = new G2();
|
||
|
|
Bn256.mul(pub, Q, s); // public key = sQ
|
||
|
|
|
||
|
|
String m = "signature test";
|
||
|
|
G1 H = new G1();
|
||
|
|
H.hashAndMapToG1(m); // H = Hash(m)
|
||
|
|
G1 sign = new G1();
|
||
|
|
Bn256.mul(sign, H, s); // signature of m = s H
|
||
|
|
|
||
|
|
GT e1 = new GT();
|
||
|
|
GT e2 = new GT();
|
||
|
|
Bn256.pairing(e1, pub, H); // e1 = e(s Q, H)
|
||
|
|
Bn256.pairing(e2, Q, sign); // e2 = e(Q, s H);
|
||
|
|
assertBool("verify signature", e1.equals(e2));
|
||
|
|
```
|
||
|
|
|
||
|
|
# Make test
|
||
|
|
```
|
||
|
|
cd java
|
||
|
|
make test_bn256
|
||
|
|
```
|
||
|
|
|
||
|
|
# Sample code
|
||
|
|
[Bn256Test.java](https://github.com/herumi/mcl/blob/master/java/Bn256Test.java)
|