ECDiffieHellmanCngPublicKey.cs

Go to the documentation of this file.

namespace System.Security.Cryptography;
 
public sealed class ECDiffieHellmanCngPublicKey : ECDiffieHellmanPublicKey
{
    private readonly CngKeyBlobFormat _format;
 
    private readonly string _curveName;
 
    private bool _disposed;
 
    public CngKeyBlobFormat BlobFormat => _format;
 
    internal ECDiffieHellmanCngPublicKey(byte[] keyBlob, string curveName, CngKeyBlobFormat format)
        : base(keyBlob)
    {
        _format = format;
        _curveName = curveName;
    }
 
    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            _disposed = true;
        }
        base.Dispose(disposing);
    }
 
    public override string ToXmlString()
    {
        throw new PlatformNotSupportedException();
    }
 
    public static ECDiffieHellmanCngPublicKey FromXmlString(string xml)
    {
        throw new PlatformNotSupportedException();
    }
 
    public static ECDiffieHellmanPublicKey FromByteArray(byte[] publicKeyBlob, CngKeyBlobFormat format)
    {
        if (publicKeyBlob == null)
        {
            throw new ArgumentNullException("publicKeyBlob");
        }
        if (format == null)
        {
            throw new ArgumentNullException("format");
        }
        using CngKey cngKey = CngKey.Import(publicKeyBlob, format);
        if (cngKey.AlgorithmGroup != CngAlgorithmGroup.ECDiffieHellman)
        {
            throw new ArgumentException(System.SR.Cryptography_ArgECDHRequiresECDHKey);
        }
        return new ECDiffieHellmanCngPublicKey(publicKeyBlob, null, format);
    }
 
    internal static ECDiffieHellmanCngPublicKey FromKey(CngKey key)
    {
        CngKeyBlobFormat format;
        string curveName;
        byte[] keyBlob = System.Security.Cryptography.ECCng.ExportKeyBlob(key, includePrivateParameters: false, out format, out curveName);
        return new ECDiffieHellmanCngPublicKey(keyBlob, curveName, format);
    }
 
    public CngKey Import()
    {
        if (_disposed)
        {
            throw new ObjectDisposedException("ECDiffieHellmanCngPublicKey");
        }
        return CngKey.Import(ToByteArray(), _curveName, BlobFormat);
    }
 
    public override ECParameters ExportExplicitParameters()
    {
        using CngKey key = Import();
        ECParameters ecParams = default(ECParameters);
        byte[] ecBlob = System.Security.Cryptography.ECCng.ExportFullKeyBlob(key, includePrivateParameters: false);
        System.Security.Cryptography.ECCng.ExportPrimeCurveParameters(ref ecParams, ecBlob, includePrivateParameters: false);
        return ecParams;
    }
 
    public override ECParameters ExportParameters()
    {
        using CngKey cngKey = Import();
        ECParameters ecParams = default(ECParameters);
        string oidValue;
        string curveName = cngKey.GetCurveName(out oidValue);
        if (string.IsNullOrEmpty(curveName))
        {
            byte[] ecBlob = System.Security.Cryptography.ECCng.ExportFullKeyBlob(cngKey, includePrivateParameters: false);
            System.Security.Cryptography.ECCng.ExportPrimeCurveParameters(ref ecParams, ecBlob, includePrivateParameters: false);
        }
        else
        {
            byte[] ecBlob2 = System.Security.Cryptography.ECCng.ExportKeyBlob(cngKey, includePrivateParameters: false);
            System.Security.Cryptography.ECCng.ExportNamedCurveParameters(ref ecParams, ecBlob2, includePrivateParameters: false);
            ecParams.Curve = ECCurve.CreateFromFriendlyName(curveName);
        }
        return ecParams;
    }
}