ECCurve.cs

Go to the documentation of this file.

using System.Diagnostics;
using System.Runtime.Versioning;
 
namespace System.Security.Cryptography;
 
[DebuggerDisplay("ECCurve: {Oid}")]
[UnsupportedOSPlatform("browser")]
public struct ECCurve
{
    public enum ECCurveType
    {
        Implicit,
        PrimeShortWeierstrass,
        PrimeTwistedEdwards,
        PrimeMontgomery,
        Characteristic2,
        Named
    }
 
    public static class NamedCurves
    {
        public static ECCurve brainpoolP160r1 => CreateFromFriendlyName("brainpoolP160r1");
 
        public static ECCurve brainpoolP160t1 => CreateFromFriendlyName("brainpoolP160t1");
 
        public static ECCurve brainpoolP192r1 => CreateFromFriendlyName("brainpoolP192r1");
 
        public static ECCurve brainpoolP192t1 => CreateFromFriendlyName("brainpoolP192t1");
 
        public static ECCurve brainpoolP224r1 => CreateFromFriendlyName("brainpoolP224r1");
 
        public static ECCurve brainpoolP224t1 => CreateFromFriendlyName("brainpoolP224t1");
 
        public static ECCurve brainpoolP256r1 => CreateFromFriendlyName("brainpoolP256r1");
 
        public static ECCurve brainpoolP256t1 => CreateFromFriendlyName("brainpoolP256t1");
 
        public static ECCurve brainpoolP320r1 => CreateFromFriendlyName("brainpoolP320r1");
 
        public static ECCurve brainpoolP320t1 => CreateFromFriendlyName("brainpoolP320t1");
 
        public static ECCurve brainpoolP384r1 => CreateFromFriendlyName("brainpoolP384r1");
 
        public static ECCurve brainpoolP384t1 => CreateFromFriendlyName("brainpoolP384t1");
 
        public static ECCurve brainpoolP512r1 => CreateFromFriendlyName("brainpoolP512r1");
 
        public static ECCurve brainpoolP512t1 => CreateFromFriendlyName("brainpoolP512t1");
 
        public static ECCurve nistP256 => CreateFromValueAndName("1.2.840.10045.3.1.7", "nistP256");
 
        public static ECCurve nistP384 => CreateFromValueAndName("1.3.132.0.34", "nistP384");
 
        public static ECCurve nistP521 => CreateFromValueAndName("1.3.132.0.35", "nistP521");
    }
 
    public byte[]? A;
 
    public byte[]? B;
 
    public ECPoint G;
 
    public byte[]? Order;
 
    public byte[]? Cofactor;
 
    public byte[]? Seed;
 
    public ECCurveType CurveType;
 
    public HashAlgorithmName? Hash;
 
    public byte[]? Polynomial;
 
    public byte[]? Prime;
 
    private Oid _oid;
 
    public Oid Oid
    {
        get
        {
            return _oid;
        }
        private set
        {
            if (value == null)
            {
                throw new ArgumentNullException("Oid");
            }
            if (string.IsNullOrEmpty(value.Value) && string.IsNullOrEmpty(value.FriendlyName))
            {
                throw new ArgumentException(System.SR.Cryptography_InvalidCurveOid);
            }
            _oid = value;
        }
    }
 
    public bool IsPrime
    {
        get
        {
            if (CurveType != ECCurveType.PrimeShortWeierstrass && CurveType != ECCurveType.PrimeMontgomery)
            {
                return CurveType == ECCurveType.PrimeTwistedEdwards;
            }
            return true;
        }
    }
 
    public bool IsCharacteristic2 => CurveType == ECCurveType.Characteristic2;
 
    public bool IsExplicit
    {
        get
        {
            if (!IsPrime)
            {
                return IsCharacteristic2;
            }
            return true;
        }
    }
 
    public bool IsNamed => CurveType == ECCurveType.Named;
 
    public static ECCurve CreateFromOid(Oid curveOid)
    {
        ECCurve result = default(ECCurve);
        result.CurveType = ECCurveType.Named;
        result.Oid = curveOid;
        return result;
    }
 
    public static ECCurve CreateFromFriendlyName(string oidFriendlyName)
    {
        if (oidFriendlyName == null)
        {
            throw new ArgumentNullException("oidFriendlyName");
        }
        return CreateFromValueAndName(null, oidFriendlyName);
    }
 
    public static ECCurve CreateFromValue(string oidValue)
    {
        if (oidValue == null)
        {
            throw new ArgumentNullException("oidValue");
        }
        return CreateFromValueAndName(oidValue, null);
    }
 
    private static ECCurve CreateFromValueAndName(string oidValue, string oidFriendlyName)
    {
        Oid oid = null;
        if (oidValue == null && oidFriendlyName != null)
        {
            try
            {
                oid = System.Security.Cryptography.Oid.FromFriendlyName(oidFriendlyName, OidGroup.PublicKeyAlgorithm);
            }
            catch (CryptographicException)
            {
            }
        }
        if (oid == null)
        {
            oid = new Oid(oidValue, oidFriendlyName);
        }
        return CreateFromOid(oid);
    }
 
    public void Validate()
    {
        if (IsNamed)
        {
            if (HasAnyExplicitParameters())
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidECNamedCurve);
            }
            if (Oid == null || (string.IsNullOrEmpty(Oid.FriendlyName) && string.IsNullOrEmpty(Oid.Value)))
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidCurveOid);
            }
        }
        else if (IsExplicit)
        {
            bool flag = false;
            if (A == null || B == null || B.Length != A.Length || G.X == null || G.X.Length != A.Length || G.Y == null || G.Y.Length != A.Length || Order == null || Order.Length == 0 || Cofactor == null || Cofactor.Length == 0)
            {
                flag = true;
            }
            if (IsPrime)
            {
                if (!flag && (Prime == null || Prime.Length != A.Length))
                {
                    flag = true;
                }
                if (flag)
                {
                    throw new CryptographicException(System.SR.Cryptography_InvalidECPrimeCurve);
                }
            }
            else if (IsCharacteristic2)
            {
                if (!flag && (Polynomial == null || Polynomial.Length == 0))
                {
                    flag = true;
                }
                if (flag)
                {
                    throw new CryptographicException(System.SR.Cryptography_InvalidECCharacteristic2Curve);
                }
            }
        }
        else if (HasAnyExplicitParameters() || Oid != null)
        {
            throw new CryptographicException(System.SR.Format(System.SR.Cryptography_CurveNotSupported, CurveType.ToString()));
        }
    }
 
    private bool HasAnyExplicitParameters()
    {
        if (A == null && B == null && G.X == null && G.Y == null && Order == null && Cofactor == null && Prime == null && Polynomial == null && Seed == null)
        {
            return Hash.HasValue;
        }
        return true;
    }
}