<PackageReference Include="BouncyCastle.Cryptography" Version="2.4.0" />

Org.BouncyCastle.Asn1.Cms.KeyAgreeRecipientIdentifier

public static KeyAgreeRecipientIdentifier GetInstance(object obj)

public static KeyAgreeRecipientIdentifier GetInstance(Asn1TaggedObject obj, bool isExplicit)