18212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrompackage org.bouncycastle.asn1.x9;
28212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
38212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstromimport java.math.BigInteger;
48212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
58212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstromimport org.bouncycastle.asn1.ASN1EncodableVector;
64c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstromimport org.bouncycastle.asn1.ASN1Integer;
74c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstromimport org.bouncycastle.asn1.ASN1Object;
84c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstromimport org.bouncycastle.asn1.ASN1ObjectIdentifier;
94c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstromimport org.bouncycastle.asn1.ASN1Primitive;
108212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstromimport org.bouncycastle.asn1.ASN1Sequence;
118212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstromimport org.bouncycastle.asn1.DERSequence;
128212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
138212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom/**
148212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom * ASN.1 def for Elliptic-Curve Field ID structure. See
158212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom * X9.62, for further details.
168212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom */
178212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrompublic class X9FieldID
184c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    extends ASN1Object
198212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    implements X9ObjectIdentifiers
208212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom{
214c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    private ASN1ObjectIdentifier     id;
224c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    private ASN1Primitive parameters;
238212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
248212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    /**
258212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * Constructor for elliptic curves over prime fields
268212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * <code>F<sub>2</sub></code>.
278212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * @param primeP The prime <code>p</code> defining the prime field.
288212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     */
298212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    public X9FieldID(BigInteger primeP)
308212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
318212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        this.id = prime_field;
324c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom        this.parameters = new ASN1Integer(primeP);
338212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
348212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
358212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    /**
368212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * Constructor for elliptic curves over binary fields
378212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * <code>F<sub>2<sup>m</sup></sub></code>.
388212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * @param m  The exponent <code>m</code> of
398212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * <code>F<sub>2<sup>m</sup></sub></code>.
408212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * @param k1 The integer <code>k1</code> where <code>x<sup>m</sup> +
418212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
428212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * represents the reduction polynomial <code>f(z)</code>.
438212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * @param k2 The integer <code>k2</code> where <code>x<sup>m</sup> +
448212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
458212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * represents the reduction polynomial <code>f(z)</code>.
468212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * @param k3 The integer <code>k3</code> where <code>x<sup>m</sup> +
478212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * x<sup>k3</sup> + x<sup>k2</sup> + x<sup>k1</sup> + 1</code>
488212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * represents the reduction polynomial <code>f(z)</code>..
498212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     */
508212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    public X9FieldID(int m, int k1, int k2, int k3)
518212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
528212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        this.id = characteristic_two_field;
538212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        ASN1EncodableVector fieldIdParams = new ASN1EncodableVector();
544c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom        fieldIdParams.add(new ASN1Integer(m));
558212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
568212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        if (k2 == 0)
578212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        {
588212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom            fieldIdParams.add(tpBasis);
594c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom            fieldIdParams.add(new ASN1Integer(k1));
608212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        }
618212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        else
628212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        {
638212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom            fieldIdParams.add(ppBasis);
648212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom            ASN1EncodableVector pentanomialParams = new ASN1EncodableVector();
654c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom            pentanomialParams.add(new ASN1Integer(k1));
664c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom            pentanomialParams.add(new ASN1Integer(k2));
674c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom            pentanomialParams.add(new ASN1Integer(k3));
688212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom            fieldIdParams.add(new DERSequence(pentanomialParams));
698212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        }
708212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
718212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        this.parameters = new DERSequence(fieldIdParams);
728212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
738212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
748212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    public X9FieldID(
758212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        ASN1Sequence  seq)
768212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
774c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom        this.id = (ASN1ObjectIdentifier)seq.getObjectAt(0);
784c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom        this.parameters = (ASN1Primitive)seq.getObjectAt(1);
798212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
808212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
814c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    public ASN1ObjectIdentifier getIdentifier()
828212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
838212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        return id;
848212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
858212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
864c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    public ASN1Primitive getParameters()
878212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
888212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        return parameters;
898212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
908212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
918212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    /**
928212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * Produce a DER encoding of the following structure.
938212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * <pre>
948212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     *  FieldID ::= SEQUENCE {
958212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     *      fieldType       FIELD-ID.&amp;id({IOSet}),
968212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     *      parameters      FIELD-ID.&amp;Type({IOSet}{&#64;fieldType})
978212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     *  }
988212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     * </pre>
998212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom     */
1004c111300c39cb2e27f07fc2ae3b00e23ed4443b2Brian Carlstrom    public ASN1Primitive toASN1Primitive()
1018212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    {
1028212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        ASN1EncodableVector v = new ASN1EncodableVector();
1038212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
1048212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        v.add(this.id);
1058212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        v.add(this.parameters);
1068212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom
1078212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom        return new DERSequence(v);
1088212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom    }
1098212855a312dc8ebe081a3e08b1d2d8f8757af02Brian Carlstrom}
110