BLS12_381G2 (Bouncy Castle Library 1.85 API Specification)

java.lang.Object
- org.bouncycastle.crypto.bls.BLS12_381G2

```
public class BLS12_381G2
extends java.lang.Object
```
Curve parameters for BLS12-381 G2, the prime-order subgroup of E(Fp^2) defined by y^2 = x^3 + 4 * (1 + I) over Fp^2.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.math.BigInteger`	`COFACTOR`	G2 cofactor.
`static java.math.BigInteger`	`H_EFF`	Effective cofactor for hash-to-curve (RFC 9380 sec. 8.8.2).
`static java.math.BigInteger`	`ORDER`	G2 prime-order subgroup order — identical to G1's, since pairing-friendly curves have G1 and G2 share the same scalar field.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type Method Description

static BLS12_381G2Point getGenerator()
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - ORDER
```
public static final java.math.BigInteger ORDER
```
    G2 prime-order subgroup order — identical to G1's, since pairing-friendly curves have G1 and G2 share the same scalar field.
  - COFACTOR
```
public static final java.math.BigInteger COFACTOR
```
    G2 cofactor.
  - H_EFF
```
public static final java.math.BigInteger H_EFF
```
    Effective cofactor for hash-to-curve (RFC 9380 sec. 8.8.2). Multiplying any point on E(Fp^2) by h_eff lands in the prime-order subgroup; the value is chosen for compatibility with the Budroni-Pintore optimised cofactor clearing.
- Method Detail
  - getGenerator
```
public static BLS12_381G2Point getGenerator()
```
    Returns:
    
    the standard generator G2 of the prime-order subgroup, as a fresh affine point. The returned point is verified against the curve equation.