Estoy tratando de crear un certificado de confianza autofirmado. Estoy usando Bouncy Castle de nuget, y la respuesta enesta pregunta. Este es el código en esa página:

public static X509Certificate2 GenerateSelfSignedCertificate(string subjectName, string issuerName, AsymmetricKeyParameter issuerPrivKey,  int keyStrength = 2048)
{
// Generating Random Numbers
var randomGenerator = new CryptoApiRandomGenerator();
var random = new SecureRandom(randomGenerator);

// The Certificate Generator
var certificateGenerator = new X509V3CertificateGenerator();

// Serial Number
var serialNumber = BigIntegers.CreateRandomInRange(BigInteger.One, BigInteger.ValueOf(Int64.MaxValue), random);
certificateGenerator.SetSerialNumber(serialNumber);

// Signature Algorithm
const string signatureAlgorithm = "SHA256WithRSA";
certificateGenerator.SetSignatureAlgorithm(signatureAlgorithm);

// Issuer and Subject Name
var subjectDN = new X509Name(subjectName);
var issuerDN = issuerName;
certificateGenerator.SetIssuerDN(issuerDN);
certificateGenerator.SetSubjectDN(subjectDN);

// Valid For
var notBefore = DateTime.UtcNow.Date;
var notAfter = notBefore.AddYears(2);

certificateGenerator.SetNotBefore(notBefore);
certificateGenerator.SetNotAfter(notAfter);

// Subject Public Key
AsymmetricCipherKeyPair subjectKeyPair;
var keyGenerationParameters = new KeyGenerationParameters(random, keyStrength);
var keyPairGenerator = new RsaKeyPairGenerator();
keyPairGenerator.Init(keyGenerationParameters);
subjectKeyPair = keyPairGenerator.GenerateKeyPair();

certificateGenerator.SetPublicKey(subjectKeyPair.Public);

// Generating the Certificate
var issuerKeyPair = subjectKeyPair;

// selfsign certificate
var certificate = certificateGenerator.Generate(issuerPrivKey, random);

// correcponding private key
PrivateKeyInfo info = PrivateKeyInfoFactory.CreatePrivateKeyInfo(subjectKeyPair.Private);


// merge into X509Certificate2
var x509 = new System.Security.Cryptography.X509Certificates.X509Certificate2(certificate.GetEncoded());

var seq = (Asn1Sequence)Asn1Object.FromByteArray(info.PrivateKey.GetDerEncoded());
if (seq.Count != 9)
    throw new PemException("malformed sequence in RSA private key");

var rsa = new RsaPrivateKeyStructure(seq);
RsaPrivateCrtKeyParameters rsaparams = new RsaPrivateCrtKeyParameters(
    rsa.Modulus, rsa.PublicExponent, rsa.PrivateExponent, rsa.Prime1, rsa.Prime2, rsa.Exponent1, rsa.Exponent2, rsa.Coefficient);

x509.PrivateKey = DotNetUtilities.ToRSA(rsaparams);
return x509;
}


public static AsymmetricKeyParameter GenerateCACertificate(string subjectName, int keyStrength = 2048)
{
// Generating Random Numbers
var randomGenerator = new CryptoApiRandomGenerator();
var random = new SecureRandom(randomGenerator);

// The Certificate Generator
var certificateGenerator = new X509V3CertificateGenerator();

// Serial Number
var serialNumber = BigIntegers.CreateRandomInRange(BigInteger.One, BigInteger.ValueOf(Int64.MaxValue), random);
certificateGenerator.SetSerialNumber(serialNumber);

// Signature Algorithm
const string signatureAlgorithm = "SHA256WithRSA";
certificateGenerator.SetSignatureAlgorithm(signatureAlgorithm);

// Issuer and Subject Name
var subjectDN = new X509Name(subjectName);
var issuerDN = subjectDN;
certificateGenerator.SetIssuerDN(issuerDN);
certificateGenerator.SetSubjectDN(subjectDN);

// Valid For
var notBefore = DateTime.UtcNow.Date;
var notAfter = notBefore.AddYears(2);

certificateGenerator.SetNotBefore(notBefore);
certificateGenerator.SetNotAfter(notAfter);

// Subject Public Key
AsymmetricCipherKeyPair subjectKeyPair;
var keyGenerationParameters = new KeyGenerationParameters(random, keyStrength);
var keyPairGenerator = new RsaKeyPairGenerator();
keyPairGenerator.Init(keyGenerationParameters);
subjectKeyPair = keyPairGenerator.GenerateKeyPair();

certificateGenerator.SetPublicKey(subjectKeyPair.Public);

// Generating the Certificate
var issuerKeyPair = subjectKeyPair;

// selfsign certificate
var certificate = certificateGenerator.Generate(issuerKeyPair.Private, random);
var x509 = new System.Security.Cryptography.X509Certificates.X509Certificate2(certificate.GetEncoded());
// Add CA certificate to Root store
addCertToStore(cert, StoreName.Root, StoreLocation.CurrentUser);

return issuerKeyPair.Private;
}

Hasta ahora, todo bien, pero los métodos "SetSignatureAlgorithm" y "Generate" están marcados como obsoletos. Intellisense sugiere usar un "ISignatureFactory", y ahí es donde me perdí. ¿Alguien me puede apuntar en la dirección correcta?