All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.bouncycastle.asn1.x9.DomainParameters Maven / Gradle / Ivy

Go to download

The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.

The newest version!
package org.bouncycastle.asn1.x9;

import java.math.BigInteger;
import java.util.Enumeration;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERSequence;

/**
 * X9.44 Diffie-Hellman domain parameters.
 * 
 *    DomainParameters ::= SEQUENCE {
 *       p                INTEGER,           -- odd prime, p=jq +1
 *       g                INTEGER,           -- generator, g
 *       q                INTEGER,           -- factor of p-1
 *       j                INTEGER OPTIONAL,  -- subgroup factor, j>= 2
 *       validationParams  ValidationParams OPTIONAL
 *    }
 * 
*/ public class DomainParameters extends ASN1Object { private final ASN1Integer p, g, q, j; private final ValidationParams validationParams; /** * Return a DomainParameters object from the passed in tagged object. * * @param obj a tagged object. * @param explicit true if the contents of the object is explictly tagged, false otherwise. * @return a DomainParameters */ public static DomainParameters getInstance(ASN1TaggedObject obj, boolean explicit) { return getInstance(ASN1Sequence.getInstance(obj, explicit)); } /** * Return a DomainParameters object from the passed in object. * * @param obj an object for conversion or a byte[]. * @return a DomainParameters */ public static DomainParameters getInstance(Object obj) { if (obj instanceof DomainParameters) { return (DomainParameters)obj; } else if (obj != null) { return new DomainParameters(ASN1Sequence.getInstance(obj)); } return null; } /** * Base constructor - the full domain parameter set. * * @param p the prime p defining the Galois field. * @param g the generator of the multiplicative subgroup of order g. * @param q specifies the prime factor of p - 1 * @param j optionally specifies the value that satisfies the equation p = jq+1 * @param validationParams parameters for validating these domain parameters. */ public DomainParameters(BigInteger p, BigInteger g, BigInteger q, BigInteger j, ValidationParams validationParams) { if (p == null) { throw new IllegalArgumentException("'p' cannot be null"); } if (g == null) { throw new IllegalArgumentException("'g' cannot be null"); } if (q == null) { throw new IllegalArgumentException("'q' cannot be null"); } this.p = new ASN1Integer(p); this.g = new ASN1Integer(g); this.q = new ASN1Integer(q); if (j != null) { this.j = new ASN1Integer(j); } else { this.j = null; } this.validationParams = validationParams; } private DomainParameters(ASN1Sequence seq) { if (seq.size() < 3 || seq.size() > 5) { throw new IllegalArgumentException("Bad sequence size: " + seq.size()); } Enumeration e = seq.getObjects(); this.p = ASN1Integer.getInstance(e.nextElement()); this.g = ASN1Integer.getInstance(e.nextElement()); this.q = ASN1Integer.getInstance(e.nextElement()); ASN1Encodable next = getNext(e); if (next != null && next instanceof ASN1Integer) { this.j = ASN1Integer.getInstance(next); next = getNext(e); } else { this.j = null; } if (next != null) { this.validationParams = ValidationParams.getInstance(next.toASN1Primitive()); } else { this.validationParams = null; } } private static ASN1Encodable getNext(Enumeration e) { return e.hasMoreElements() ? (ASN1Encodable)e.nextElement() : null; } /** * Return the prime p defining the Galois field. * * @return the prime p. */ public BigInteger getP() { return this.p.getPositiveValue(); } /** * Return the generator of the multiplicative subgroup of order g. * * @return the generator g. */ public BigInteger getG() { return this.g.getPositiveValue(); } /** * Return q, the prime factor of p - 1 * * @return q value */ public BigInteger getQ() { return this.q.getPositiveValue(); } /** * Return the value that satisfies the equation p = jq+1 (if present). * * @return j value or null. */ public BigInteger getJ() { if (this.j == null) { return null; } return this.j.getPositiveValue(); } /** * Return the validation parameters for this set (if present). * * @return validation parameters, or null if absent. */ public ValidationParams getValidationParams() { return this.validationParams; } /** * Return an ASN.1 primitive representation of this object. * * @return a DERSequence containing the parameter values. */ public ASN1Primitive toASN1Primitive() { ASN1EncodableVector v = new ASN1EncodableVector(); v.add(this.p); v.add(this.g); v.add(this.q); if (this.j != null) { v.add(this.j); } if (this.validationParams != null) { v.add(this.validationParams); } return new DERSequence(v); } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy