package org.bouncycastle.asn1.sec;

import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.asn1.x9.X9ECParametersHolder;
import org.bouncycastle.math.ec.ECConstants;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECFieldElement;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.util.Strings;

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

public class SECNamedCurves
{
    /*
     * secp224r1 (NIST P-224)
     */
    static X9ECParametersHolder secp224r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // p = 2^224 - 2^96 + 1
            BigInteger secp224r1P = new BigInteger(
                "26959946667150639794667015087019630673557916260026308143510066298881");

            // a = -3, b = b4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4
            ECCurve secp224r1Curve = new ECCurve.Fp(secp224r1P,
                new BigInteger("26959946667150639794667015087019630673557916260026308143510066298878"),
                new BigInteger("b4050a850c04b3abf54132565044b0b7d7bfd8ba270b39432355ffb4", 16));

            // x = b70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21
            ECFieldElement secp224r1x = new ECFieldElement.Fp(
                secp224r1P,
                new BigInteger("b70e0cbd6bb4bf7f321390b94a03c1d356c21122343280d6115c1d21", 16));

            // y = bd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34
            ECFieldElement secp224r1y = new ECFieldElement.Fp(
                secp224r1P,
                new BigInteger("bd376388b5f723fb4c22dfe6cd4375a05a07476444d5819985007e34", 16));

            ECPoint secp224r1BasePoint = new ECPoint.Fp(
                secp224r1Curve, secp224r1x, secp224r1y, false);

            BigInteger secp224r1n = new BigInteger("26959946667150639794667015087019625940457807714424391721682722368061");

            BigInteger secp224r1h = new BigInteger("1");

//    static final byte[] secp224r1Seed = (Hex.decode("bd71344799d5c7fcdc45b59fa3b9ab8f6a948bc5"));
            byte[] secp224r1Seed = null;

            return new X9ECParameters(
                secp224r1Curve,
                secp224r1BasePoint,
                secp224r1n,
                secp224r1h,
                secp224r1Seed);
        }
    };

    /*
     * secp256r1 (NIST P-256)
     */
    static X9ECParametersHolder secp256r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // p = 2^256 - 2^224 + 2^192 + 2^96 - 1
            BigInteger secp256r1P = new BigInteger(
                "115792089210356248762697446949407573530086143415290314195533631308867097853951");

            // a = -3, b = 5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b
            ECCurve secp256r1Curve = new ECCurve.Fp(secp256r1P,
                new BigInteger("115792089210356248762697446949407573530086143415290314195533631308867097853948"),
                new BigInteger("5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b", 16));

            // x = 6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296
            ECFieldElement secp256r1x = new ECFieldElement.Fp(
                secp256r1P,
                new BigInteger("6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296", 16));

            // y = 4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5
            ECFieldElement secp256r1y = new ECFieldElement.Fp(
                secp256r1P,
                new BigInteger("4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5", 16));

            ECPoint secp256r1BasePoint = new ECPoint.Fp(
                secp256r1Curve, secp256r1x, secp256r1y, false);

            BigInteger secp256r1n = new BigInteger("115792089210356248762697446949407573529996955224135760342422259061068512044369");

            BigInteger secp256r1h = new BigInteger("1");

//    static final byte[] secp256r1Seed = (Hex.decode("c49d360886e704936a6678e1139d26b7819f7e90"));
            byte[] secp256r1Seed = null;

            return new X9ECParameters(
                secp256r1Curve,
                secp256r1BasePoint,
                secp256r1n,
                secp256r1h,
                secp256r1Seed);
        }
    };

    /*
     * secp384r1 (NIST P-384)
     */
    static X9ECParametersHolder secp384r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // p = 2^384 - 2^128 - 2^96 + 2^32 - 1

            BigInteger secp384r1P = new BigInteger(
                "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFF", 16);

            // a, b
            ECCurve secp384r1Curve = new ECCurve.Fp(secp384r1P,
                new BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFC", 16),
                new BigInteger("B3312FA7E23EE7E4988E056BE3F82D19181D9C6EFE8141120314088F5013875AC656398D8A2ED19D2A85C8EDD3EC2AEF", 16));

            // x
            ECFieldElement secp384r1x = new ECFieldElement.Fp(
                secp384r1P,
                new BigInteger("AA87CA22BE8B05378EB1C71EF320AD746E1D3B628BA79B9859F741E082542A385502F25DBF55296C3A545E3872760AB7", 16));

            // y
            ECFieldElement secp384r1y = new ECFieldElement.Fp(
                secp384r1P,
                new BigInteger("3617DE4A96262C6F5D9E98BF9292DC29F8F41DBD289A147CE9DA3113B5F0B8C00A60B1CE1D7E819D7A431D7C90EA0E5F", 16));

            ECPoint secp384r1BasePoint = new ECPoint.Fp(
                secp384r1Curve, secp384r1x, secp384r1y, false);

            BigInteger secp384r1n = new BigInteger("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC7634D81F4372DDF581A0DB248B0A77AECEC196ACCC52###########", 16);

            BigInteger secp384r1h = new BigInteger("1");

//    static final byte[] secp384r1Seed = (Hex.decode("A335926AA319A27A1D00896A6773A4827ACDAC73"));
            byte[] secp384r1Seed = null;

            return new X9ECParameters(
                secp384r1Curve,
                secp384r1BasePoint,
                secp384r1n,
                secp384r1h,
                secp384r1Seed);
        }
    };

    /*
     * secp521r1 - (NIST P-521)
     */
    static X9ECParametersHolder secp521r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // p = 2^521 - 1
            BigInteger secp521r1P = new BigInteger(
                "6864797660130609714981900799081393217269435300143305409394463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057151");

            // a = -3, b = 051953eb9618e1c9a1f929a21a0b68540eea2da725b99b315f3b8b489918ef109e156193951ec7e937b1652c0bd3bb1bf073573df883d2c34f1ef451fd46b503f00
            ECCurve secp521r1Curve = new ECCurve.Fp(secp521r1P,
                new BigInteger("6864797660130609714981900799081393217269435300143305409394463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057148"),
                new BigInteger("051953eb9618e1c9a1f929a21a0b68540eea2da725b99b315f3b8b489918ef109e156193951ec7e937b1652c0bd3bb1bf073573df883d2c34f1ef451fd46b503f00", 16));

            // x = c6858e06b70404e9cd9e3ecb662395b4429c648139053fb521f828af606b4d3dbaa14b5e77efe75928fe1dc127a2ffa8de3348b3c1856a429bf97e7e31c2e5bd66
            ECFieldElement secp521r1x = new ECFieldElement.Fp(
                secp521r1P,
                new BigInteger("c6858e06b70404e9cd9e3ecb662395b4429c648139053fb521f828af606b4d3dbaa14b5e77efe75928fe1dc127a2ffa8de3348b3c1856a429bf97e7e31c2e5bd66", 16));

            // y = 11839296a789a3bc0045c8a5fb42c7d1bd998f54449579b446817afbd17273e662c97ee72995ef42640c550b9013fad0761353c7086a272c24088be94769fd16650
            ECFieldElement secp521r1y = new ECFieldElement.Fp(
                secp521r1P,
                new BigInteger("11839296a789a3bc0045c8a5fb42c7d1bd998f54449579b446817afbd17273e662c97ee72995ef42640c550b9013fad0761353c7086a272c24088be94769fd16650", 16));

            ECPoint secp521r1BasePoint = new ECPoint.Fp(
                secp521r1Curve, secp521r1x, secp521r1y, false);

            BigInteger secp521r1n = new BigInteger("6864797660130609714981900799081393217269435300143305409394463459185543183397655394245057746333217197532963996371363321113864768612440380340372808892707005449");

            BigInteger secp521r1h = new BigInteger("1");

//    byte[] secp521r1Seed = (Hex.decode("d09e8800291cb85396cc6717393284aaa0da64ba"));
            byte[] secp521r1Seed = null;

            return new X9ECParameters(
                secp521r1Curve,
                secp521r1BasePoint,
                secp521r1n,
                secp521r1h,
                secp521r1Seed);
        }
    };

    /*
     * sect163r2 (NIST B-163)
     */
    static X9ECParametersHolder sect163r2 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // m = 163, k1 = 3, k2 = 6, k3 = 7
            int sect163r2m = 163;
            int sect163r2k1 = 3;
            int sect163r2k2 = 6;
            int sect163r2k3 = 7;

            // a = 1
            BigInteger sect163r2a = ECConstants.ONE;

            // b = 20a601907b8c953ca1481eb10512f78744a3205fd
            BigInteger sect163r2b = new BigInteger("20a601907b8c953ca1481eb10512f78744a3205fd", 16);

            ECCurve sect163r2Curve = new ECCurve.F2m(sect163r2m, sect163r2k1, sect163r2k2, sect163r2k3, sect163r2a, sect163r2b);

            // x = 3f0eba16286a2d57ea0991168d4994637e8343e36
            ECFieldElement sect163r2x = new ECFieldElement.F2m(
                sect163r2m, sect163r2k1, sect163r2k2, sect163r2k3,
                new BigInteger("3f0eba16286a2d57ea0991168d4994637e8343e36", 16));

            // y = 0d51fbc6c71a0094fa2cdd545b11c5c0c7###########24f1
            ECFieldElement sect163r2y = new ECFieldElement.F2m(
                sect163r2m, sect163r2k1, sect163r2k2, sect163r2k3,
                new BigInteger("0d51fbc6c71a0094fa2cdd545b11c5c0c7###########24f1", 16));

            ECPoint sect163r2BasePoint = new ECPoint.F2m(
                sect163r2Curve, sect163r2x, sect163r2y, false);

            BigInteger sect163r2n = new BigInteger("5846006549323611672814742442876390689256843201587");

            BigInteger sect163r2h = new BigInteger("2");

            byte[] sect163r2Seed = null;

            return new X9ECParameters(
                sect163r2Curve,
                sect163r2BasePoint,
                sect163r2n,
                sect163r2h,
                sect163r2Seed);
        }
    };

    /*
     * sect233r1 (NIST B-233)
     */
    static X9ECParametersHolder sect233r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // m = 233, k1 = 74, k2 = 0, k3 = 0
            int sect233r1m = 233;
            int sect233r1k1 = 74;
            int sect233r1k2 = 0;
            int sect233r1k3 = 0;

            // a = 1
            BigInteger sect233r1a = ECConstants.ONE;

            // b = 066647ede6c332c7f8c0923bb58213b333b20e9ce4281fe115f7d8f90ad
            BigInteger sect233r1b = new BigInteger("066647ede6c332c7f8c0923bb58213b333b20e9ce4281fe115f7d8f90ad", 16);

            ECCurve sect233r1Curve = new ECCurve.F2m(sect233r1m, sect233r1k1, sect233r1k2, sect233r1k3, sect233r1a, sect233r1b);

            // x = 0fac9dfcbac8313bb2139f1bb755fef65bc391f8b36f8f8eb7371fd558b
            ECFieldElement sect233r1x = new ECFieldElement.F2m(
                sect233r1m, sect233r1k1, sect233r1k2, sect233r1k3,
                new BigInteger("0fac9dfcbac8313bb2139f1bb755fef65bc391f8b36f8f8eb7371fd558b", 16));

            // y = 1006a08a41903350678e58528bebf8a0beff867a7ca36716f7e01f81052
            ECFieldElement sect233r1y = new ECFieldElement.F2m(
                sect233r1m, sect233r1k1, sect233r1k2, sect233r1k3,
                new BigInteger("1006a08a41903350678e58528bebf8a0beff867a7ca36716f7e01f81052", 16));

            ECPoint sect233r1BasePoint = new ECPoint.F2m(
                sect233r1Curve, sect233r1x, sect233r1y, false);

            BigInteger sect233r1n = new BigInteger("6901746346790563787434755862277025555839812737345013555379383634485463");

            BigInteger sect233r1h = new BigInteger("2");

            byte[] sect233r1Seed = null;

            return new X9ECParameters(
                sect233r1Curve,
                sect233r1BasePoint,
                sect233r1n,
                sect233r1h,
                sect233r1Seed);
        }
    };


    /*
     * sect283r1 (NIST B-283)
     */
    static X9ECParametersHolder sect283r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // m = 283, k1 = 5, k2 = 7, k3 = 12
            int sect283r1m = 283;
            int sect283r1k1 = 5;
            int sect283r1k2 = 7;
            int sect283r1k3 = 12;

            // a = 1
            BigInteger sect283r1a = ECConstants.ONE;

            // b = 27b680ac8b8596da5a4af8a19a0303fca97fd7645309fa2a581485af6263e313b79a2f5
            BigInteger sect283r1b = new BigInteger("27b680ac8b8596da5a4af8a19a0303fca97fd7645309fa2a581485af6263e313b79a2f5", 16);

            ECCurve sect283r1Curve = new ECCurve.F2m(sect283r1m, sect283r1k1, sect283r1k2, sect283r1k3, sect283r1a, sect283r1b);

            // x = 5f939258db7dd90e1934f8c70b0dfec2eed25b8557eac9c80e2e198f8cdbecd86b12053
            ECFieldElement sect283r1x = new ECFieldElement.F2m(
                sect283r1m, sect283r1k1, sect283r1k2, sect283r1k3,
                new BigInteger("5f939258db7dd90e1934f8c70b0dfec2eed25b8557eac9c80e2e198f8cdbecd86b12053", 16));

            // y = 3676854fe24141cb98fe6d4b20d02b4516ff702350eddb0826779c813f0df45be8112f4
            ECFieldElement sect283r1y = new ECFieldElement.F2m(
                sect283r1m, sect283r1k1, sect283r1k2, sect283r1k3,
                new BigInteger("3676854fe24141cb98fe6d4b20d02b4516ff702350eddb0826779c813f0df45be8112f4", 16));

            ECPoint sect283r1BasePoint = new ECPoint.F2m(
                sect283r1Curve, sect283r1x, sect283r1y, false);

            BigInteger sect283r1n = new BigInteger("7770675568902916283677847627294075626569625924376904889109196526770044277787378692871");

            BigInteger sect283r1h = new BigInteger("2");

            byte[] sect283r1Seed = null;

            return new X9ECParameters(
                sect283r1Curve,
                sect283r1BasePoint,
                sect283r1n,
                sect283r1h,
                sect283r1Seed);
        }
    };


    /*
     * sect409r1 (NIST - B-409)
     */
    static X9ECParametersHolder sect409r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // m = 409, k1 = 87, k2 = 0, k3 = 0
            int sect409r1m = 409;
            int sect409r1k1 = 87;
            int sect409r1k2 = 0;
            int sect409r1k3 = 0;

            // a = 1
            BigInteger sect409r1a = ECConstants.ONE;

            // b = 21a5c2c8ee9feb5c4b9a753b7b476b7fd6422ef1f3dd674761fa99d6ac27c8a9a197b272822f6cd57a55aa4f50ae317b13545f
            BigInteger sect409r1b = new BigInteger("21a5c2c8ee9feb5c4b9a753b7b476b7fd6422ef1f3dd674761fa99d6ac27c8a9a197b272822f6cd57a55aa4f50ae317b13545f", 16);

            ECCurve sect409r1Curve = new ECCurve.F2m(sect409r1m, sect409r1k1, sect409r1k2, sect409r1k3, sect409r1a, sect409r1b);

            // x = 15d4860d088ddb3496b0c6064756260441cde4af1771d4db01ffe5b34e59703dc255a868a1180515603aeab60794e54bb7996a7
            ECFieldElement sect409r1x = new ECFieldElement.F2m(
                sect409r1m, sect409r1k1, sect409r1k2, sect409r1k3,
                new BigInteger("15d4860d088ddb3496b0c6064756260441cde4af1771d4db01ffe5b34e59703dc255a868a1180515603aeab60794e54bb7996a7", 16));

            // y = 61b1cfab6be5f32bbfa78324ed106a7636b9c5a7bd198d0158aa4f5488d08f38514f1fdf4b4f40d2181b3681c364ba0273c706
            ECFieldElement sect409r1y = new ECFieldElement.F2m(
                sect409r1m, sect409r1k1, sect409r1k2, sect409r1k3,
                new BigInteger("61b1cfab6be5f32bbfa78324ed106a7636b9c5a7bd198d0158aa4f5488d08f38514f1fdf4b4f40d2181b3681c364ba0273c706", 16));

            ECPoint sect409r1BasePoint = new ECPoint.F2m(
                sect409r1Curve, sect409r1x, sect409r1y, false);

            BigInteger sect409r1n = new BigInteger("661055968790248598951915308032771039828404682964281219284648798304157774827374805208143723762179110965979867288366567526771");

            BigInteger sect409r1h = new BigInteger("2");

            byte[] sect409r1Seed = null;

            return new X9ECParameters(
                sect409r1Curve,
                sect409r1BasePoint,
                sect409r1n,
                sect409r1h,
                sect409r1Seed);
        }
    };


    /*
     * sect571r1 (NIST - B-571)
     */
    static X9ECParametersHolder sect571r1 = new X9ECParametersHolder()
    {
        protected X9ECParameters createParameters()
        {
            // m = 571, k1 = 2, k2 = 5, k3 = 10
            int sect571r1m = 571;
            int sect571r1k1 = 2;
            int sect571r1k2 = 5;
            int sect571r1k3 = 10;

            // a = 1
            BigInteger sect571r1a = ECConstants.ONE;

            // b = 2f40e7e2221f295de297117b7f3d62f5c6a97ffcb8ceff1cd6ba8ce4a9a18ad84ffabbd8efa59332be7ad6756a66e294afd185a78ff12aa520e4de739baca0c7ffeff7f2955727a
            BigInteger sect571r1b = new BigInteger("2f40e7e2221f295de297117b7f3d62f5c6a97ffcb8ceff1cd6ba8ce4a9a18ad84ffabbd8efa59332be7ad6756a66e294afd185a78ff12aa520e4de739baca0c7ffeff7f2955727a", 16);

            ECCurve sect571r1Curve = new ECCurve.F2m(sect571r1m, sect571r1k1, sect571r1k2, sect571r1k3, sect571r1a, sect571r1b);

            // x = 303001d34b856296c16c0d40d3cd7750a93d1d2955fa80aa5f40fc8db7b2abdbde53950f4c0d293cdd711a35b67fb1499ae60038614f1394abfa3b4c850d927e1e7769c8eec2d19
            ECFieldElement sect571r1x = new ECFieldElement.F2m(
                sect571r1m, sect571r1k1, sect571r1k2, sect571r1k3,
                new BigInteger("303001d34b856296c16c0d40d3cd7750a93d1d2955fa80aa5f40fc8db7b2abdbde53950f4c0d293cdd711a35b67fb1499ae60038614f1394abfa3b4c850d927e1e7769c8eec2d19", 16));

            // y = 37bf27342da639b6dccfffeb73d69d78c6c27a6009cbbca1980f8533921e8a684423e43bab08a576291af8f461bb2a8b3531d2f0485c19b16e2f1516e23dd3c1a4827af1b8ac15b
            ECFieldElement sect571r1y = new ECFieldElement.F2m(
                sect571r1m, sect571r1k1, sect571r1k2, sect571r1k3,
                new BigInteger("37bf27342da639b6dccfffeb73d69d78c6c27a6009cbbca1980f8533921e8a684423e43bab08a576291af8f461bb2a8b3531d2f0485c19b16e2f1516e23dd3c1a4827af1b8ac15b", 16));

            ECPoint sect571r1BasePoint = new ECPoint.F2m(
                sect571r1Curve, sect571r1x, sect571r1y, false);

            BigInteger sect571r1n = new BigInteger("3864537523017258344695351890931987344298927329706434998657235251451519142289560424536143999389415773083133881121926944486246872462816813070234528288303332411393191105285703");

            BigInteger sect571r1h = new BigInteger("2");

            byte[] sect571r1Seed = null;

            return new X9ECParameters(
                sect571r1Curve,
                sect571r1BasePoint,
                sect571r1n,
                sect571r1h,
                sect571r1Seed);
        }
    };


    static final Hashtable objIds = new Hashtable();
    static final Hashtable curves = new Hashtable();
    static final Hashtable names = new Hashtable();

    static
    {
        objIds.put("sect571r1", SECObjectIdentifiers.sect571r1);
        objIds.put("sect409r1", SECObjectIdentifiers.sect409r1);
        objIds.put("sect283r1", SECObjectIdentifiers.sect283r1);
        objIds.put("sect233r1", SECObjectIdentifiers.sect233r1);
        objIds.put("sect163r2", SECObjectIdentifiers.sect163r2);
        objIds.put("secp521r1", SECObjectIdentifiers.secp521r1);
        objIds.put("secp256r1", SECObjectIdentifiers.secp256r1);
        objIds.put("secp224r1", SECObjectIdentifiers.secp224r1);
        objIds.put("secp384r1", SECObjectIdentifiers.secp384r1);

        names.put(SECObjectIdentifiers.sect571r1, "sect571r1");
        names.put(SECObjectIdentifiers.sect409r1, "sect409r1");
        names.put(SECObjectIdentifiers.sect283r1, "sect283r1");
        names.put(SECObjectIdentifiers.sect233r1, "sect233r1");
        names.put(SECObjectIdentifiers.sect163r2, "sect163r2");
        names.put(SECObjectIdentifiers.secp521r1, "secp521r1");
        names.put(SECObjectIdentifiers.secp256r1, "secp256r1");
        names.put(SECObjectIdentifiers.secp224r1, "secp224r1");
        names.put(SECObjectIdentifiers.secp384r1, "secp384r1");

        curves.put(SECObjectIdentifiers.sect571r1, sect571r1);
        curves.put(SECObjectIdentifiers.sect409r1, sect409r1);
        curves.put(SECObjectIdentifiers.sect283r1, sect283r1);
        curves.put(SECObjectIdentifiers.sect233r1, sect233r1);
        curves.put(SECObjectIdentifiers.sect163r2, sect163r2);
        curves.put(SECObjectIdentifiers.secp521r1, secp521r1);
        curves.put(SECObjectIdentifiers.secp256r1, secp256r1);
        curves.put(SECObjectIdentifiers.secp224r1, secp224r1);
        curves.put(SECObjectIdentifiers.secp384r1, secp384r1);
    }

    public static X9ECParameters getByName(
        String name)
    {
        DERObjectIdentifier oid = (DERObjectIdentifier)objIds.get(Strings.toLowerCase(name));

        if (oid != null)
        {
            return getByOID(oid);
        }

        return null;
    }

    /**
     * return the X9ECParameters object for the named curve represented by
     * the passed in object identifier. Null if the curve isn't present.
     *
     * @param oid an object identifier representing a named curve, if present.
     */
    public static X9ECParameters getByOID(
        DERObjectIdentifier oid)
    {
        X9ECParametersHolder holder = (X9ECParametersHolder)curves.get(oid);

        if (holder != null)
        {
            return holder.getParameters();
        }

        return null;
    }

    /**
     * return the object identifier signified by the passed in name. Null
     * if there is no object identifier associated with name.
     *
     * @return the object identifier associated with name, if present.
     */
    public static DERObjectIdentifier getOID(
        String name)
    {
        return (DERObjectIdentifier)objIds.get(Strings.toLowerCase(name));
    }

    /**
     * return the named curve name represented by the given object identifier.
     */
    public static String getName(
        DERObjectIdentifier oid)
    {
        return (String)names.get(oid);
    }

    /**
     * returns an enumeration containing the name strings for curves
     * contained in this structure.
     */
    public static Enumeration getNames()
    {
        return objIds.keys();
    }
}