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25 
26 package javax.crypto.spec;
27 
28 import java.math.BigInteger;
29 import java.security.spec.AlgorithmParameterSpec;
30 
31 /**
32  * This class specifies the set of parameters used for generating
33  * Diffie-Hellman (system) parameters for use in Diffie-Hellman key
34  * agreement. This is typically done by a central
35  * authority.
36  *
37  * <p> The central authority, after computing the parameters, must send this
38  * information to the parties looking to agree on a secret key.
39  *
40  * @author Jan Luehe
41  *
42  * @see DHParameterSpec
43  * @since 1.4
44  */
45 public class DHGenParameterSpec implements AlgorithmParameterSpec {
46 
47     // The size in bits of the prime modulus
48     private int primeSize;
49 
50     // The size in bits of the random exponent (private value)
51     private int exponentSize;
52 
53     /**
54      * Constructs a parameter set for the generation of Diffie-Hellman
55      * (system) parameters. The constructed parameter set can be used to
56      * initialize an
57      * {@link java.security.AlgorithmParameterGenerator AlgorithmParameterGenerator}
58      * object for the generation of Diffie-Hellman parameters.
59      *
60      * @param primeSize the size (in bits) of the prime modulus.
61      * @param exponentSize the size (in bits) of the random exponent.
62      */
DHGenParameterSpec(int primeSize, int exponentSize)63     public DHGenParameterSpec(int primeSize, int exponentSize) {
64         this.primeSize = primeSize;
65         this.exponentSize = exponentSize;
66     }
67 
68     /**
69      * Returns the size in bits of the prime modulus.
70      *
71      * @return the size in bits of the prime modulus
72      */
getPrimeSize()73     public int getPrimeSize() {
74         return this.primeSize;
75     }
76 
77     /**
78      * Returns the size in bits of the random exponent (private value).
79      *
80      * @return the size in bits of the random exponent (private value)
81      */
getExponentSize()82     public int getExponentSize() {
83         return this.exponentSize;
84     }
85 }
86