<PackageReference Include="Microsoft.Bcl.Cryptography" Version="11.0.0-preview.3.26207.106" />

System.Security.Cryptography.AsymmetricAlgorithmHelpers

namespace System.Security.Cryptography { internal static class AsymmetricAlgorithmHelpers { public static byte[] ConvertIeee1363ToDer(ReadOnlySpan<byte> input); public static byte[] ConvertDerToIeee1363(ReadOnlySpan<byte> input, int fieldSizeBits); } }