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25 package java.security.spec;
26 
27 import java.math.BigInteger;
28 import java.util.Objects;
29 
30 /**
31  * A class representing elliptic curve public keys as defined in RFC 7748,
32  * including the curve and other algorithm parameters. The public key is a
33  * particular point on the curve, which is represented using only its
34  * u-coordinate. A u-coordinate is an element of the field of integers modulo
35  * some value that is determined by the algorithm parameters. This field
36  * element is represented by a BigInteger which may hold any value. That is,
37  * the BigInteger is not restricted to the range of canonical field elements.
38  *
39  * @since 11
40  */
41 public class XECPublicKeySpec implements KeySpec {
42 
43     private final AlgorithmParameterSpec params;
44     private final BigInteger u;
45 
46     /**
47      * Construct a public key spec using the supplied parameters and
48      * u coordinate.
49      *
50      * @param params the algorithm parameters
51      * @param u the u-coordinate of the point, represented using a BigInteger
52      *          which may hold any value
53      *
54      * @throws NullPointerException if {@code params} or {@code u}
55      *                              is null.
56      */
XECPublicKeySpec(AlgorithmParameterSpec params, BigInteger u)57     public XECPublicKeySpec(AlgorithmParameterSpec params, BigInteger u) {
58         Objects.requireNonNull(params, "params must not be null");
59         Objects.requireNonNull(u, "u must not be null");
60 
61         this.params = params;
62         this.u = u;
63     }
64 
65     /**
66      * Get the algorithm parameters that define the curve and other settings.
67      *
68      * @return the parameters
69      */
getParams()70     public AlgorithmParameterSpec getParams() {
71         return params;
72     }
73 
74     /**
75      * Get the u coordinate of the point.
76      *
77      * @return the u-coordinate, represented using a BigInteger which may hold
78      *          any value
79      */
getU()80     public BigInteger getU() {
81         return u;
82     }
83 }
84