org.spongycastle.crypto.agreement.jpake

Class JPAKEPrimeOrderGroup

java.lang.Object

org.spongycastle.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

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()