org.bouncycastle.crypto.agreement.jpake

## Class JPAKEPrimeOrderGroup

- java.lang.Object
- - org.bouncycastle.crypto.agreement.jpake.JPAKEPrimeOrderGroup

-     public class JPAKEPrimeOrderGroup
      extends java.lang.Object

  A pre-computed prime order group for use during a J-PAKE exchange.

  Typically a Schnorr group is used. In general, J-PAKE can use any prime order group that is suitable for public key cryptography, including elliptic curve cryptography.

  See `JPAKEPrimeOrderGroups` for convenient standard groups.

  NIST publishes many groups that can be used for the desired level of security.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `JPAKEPrimeOrderGroup(java.math.BigInteger p, java.math.BigInteger q, java.math.BigInteger g)` Constructs a new `JPAKEPrimeOrderGroup`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `java.math.BigInteger` | `getG()`
    `java.math.BigInteger` | `getP()`
    `java.math.BigInteger` | `getQ()`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### JPAKEPrimeOrderGroup

          public JPAKEPrimeOrderGroup(java.math.BigInteger p,
                                      java.math.BigInteger q,
                                      java.math.BigInteger g)

      Constructs a new `JPAKEPrimeOrderGroup`.

      In general, you should use one of the pre-approved groups from `JPAKEPrimeOrderGroups`, rather than manually constructing one.

      The following basic checks are performed:

      - p-1 must be evenly divisible by q
      - g must be in [2, p-1]
      - g^q mod p must equal 1
      - p must be prime (within reasonably certainty)
      - q must be prime (within reasonably certainty)

      The prime checks are performed using `BigInteger.isProbablePrime(int)`, and are therefore subject to the same probability guarantees.

      These checks prevent trivial mistakes. However, due to the small uncertainties if p and q are not prime, advanced attacks are not prevented. Use it at your own risk.

      Throws:
        `java.lang.NullPointerException` - if any argument is null
        `java.lang.IllegalArgumentException` - if any of the above validations fail

  - ### Method Detail

    - #### getP

          public java.math.BigInteger getP()

    - #### getQ

          public java.math.BigInteger getQ()

    - #### getG

          public java.math.BigInteger getG()