JPBC部分API说明

淡淡的烟草味﹌ 2022-04-12 13:43 585阅读 0赞

## Bilinear Pairing Parameters Generators ##

双线性对参数生成器

TypeA:

TypeA  参数是通过一个椭圆曲线建立起来的：![y^\{2\}= x^\{3\}+x][y_2_ x_3_x] 在有限域Fp上建立的，其中q是素数q = 3 mod 4,G1 和 G2都是群上的点，椭圆曲线的阶r = q + 1。

TypeA的用例 r 是阶的位数，q是域的宽度，为素数双线性群。

import it.unisa.dia.gas.plaf.jpbc.pairing.a.TypeACurveGenerator;
    import it.unisa.dia.gas.plaf.jpbc.pbc.curve.PBCTypeACurveGenerator;
    
    int rBits = 160;
    int qBits = 512;
    
    // JPBC Type A pairing generator...
    ParametersGenerator pg = new TypeACurveGenerator(rBits, qBits);
    // PBC Type A pairing generator...
    ParametersGenerator pbcPg = new PBCTypeACurveGenerator(rBits, qBits);

TypeA1：使用的椭圆曲线是一样的，但是在不同的有限域上，为合数双线性群。

import it.unisa.dia.gas.plaf.jpbc.pairing.a.TypeA1CurveGenerator;
    import it.unisa.dia.gas.plaf.jpbc.pbc.curve.PBCTypeA1CurveGenerator;
    
    // JPBC Type A1 pairing generator...
    ParametersGenerator parametersGenerator = new TypeA1CurveGenerator(
        3,  // the number of primes
        517 // the bit length of each prime
    );
    
    // PBC Type A1 pairing generator. No parametrization in this case is possible.
    // By default the generator uses two primes of 512 bit length each.
    ParametersGenerator pbcPg = new PBCTypeA1CurveGenerator();

Make Immutable

使生成不可变的元素

/* Returns true if e is immutable, false otherwise. */
    
    e.isImmutable();
                    
    /* Returns an immutable copy of e. */
    
    Element immutable = e.getImmutable();

Import Export Elements

导入、导出元素

/* Converts e to bytes. The number of bytes can be determined
    by calling e.getLengthInBytes(). */
    
    byte[] bytes = e.toBytes();
                    
    /* To get back an Element from a byte array. */
    
    int bytesRead = e.setFromBytes(bytes);
                    
    /* To get back an Element from a byte array starting from a given offset.
    
    int bytesRead = e.setFromBytes(bytes, offset);
                    
    /* Sets e deterministically from a byte array.*/
    
    e.setFromHash(bytes, 0, bytes.length);

[y_2_ x_3_x]: https://private.codecogs.com/gif.latex?y%5E%7B2%7D%3D%20x%5E%7B3%7D&plus;x