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using System;
using System.Collections;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Sec;
using Org.BouncyCastle.Asn1.X9;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.Collections;
namespace Org.BouncyCastle.Asn1.Nist
{
/**
* Utility class for fetching curves using their NIST names as published in FIPS-PUB 186-3
*/
public sealed class NistNamedCurves
{
private NistNamedCurves()
{
}
private static readonly IDictionary objIds = Platform.CreateHashtable();
private static readonly IDictionary names = Platform.CreateHashtable();
private static void DefineCurveAlias(
string name,
DerObjectIdentifier oid)
{
objIds.Add(Platform.ToUpperInvariant(name), oid);
names.Add(oid, name);
}
static NistNamedCurves()
{
DefineCurveAlias("B-163", SecObjectIdentifiers.SecT163r2);
DefineCurveAlias("B-233", SecObjectIdentifiers.SecT233r1);
DefineCurveAlias("B-283", SecObjectIdentifiers.SecT283r1);
DefineCurveAlias("B-409", SecObjectIdentifiers.SecT409r1);
DefineCurveAlias("B-571", SecObjectIdentifiers.SecT571r1);
DefineCurveAlias("K-163", SecObjectIdentifiers.SecT163k1);
DefineCurveAlias("K-233", SecObjectIdentifiers.SecT233k1);
DefineCurveAlias("K-283", SecObjectIdentifiers.SecT283k1);
DefineCurveAlias("K-409", SecObjectIdentifiers.SecT409k1);
DefineCurveAlias("K-571", SecObjectIdentifiers.SecT571k1);
DefineCurveAlias("P-192", SecObjectIdentifiers.SecP192r1);
DefineCurveAlias("P-224", SecObjectIdentifiers.SecP224r1);
DefineCurveAlias("P-256", SecObjectIdentifiers.SecP256r1);
DefineCurveAlias("P-384", SecObjectIdentifiers.SecP384r1);
DefineCurveAlias("P-521", SecObjectIdentifiers.SecP521r1);
}
public static X9ECParameters GetByName(
string name)
{
DerObjectIdentifier oid = GetOid(name);
return oid == null ? null : GetByOid(oid);
}
/**
* 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)
{
return SecNamedCurves.GetByOid(oid);
}
/**
* 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[Platform.ToUpperInvariant(name)];
}
/**
* return the named curve name represented by the given object identifier.
*/
public static string GetName(
DerObjectIdentifier oid)
{
return (string) names[oid];
}
/**
* returns an enumeration containing the name strings for curves
* contained in this structure.
*/
public static IEnumerable Names
{
get { return new EnumerableProxy(names.Values); }
}
}
}
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