Mark enums with FlagsAttribute (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1027)

In externally visible method 'CrlBuilder CrlBuilder.Create(IX509CRL crl)', validate parameter 'crl' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

In externally visible method 'T X509Extensions.FindExtension<T>(X509Certificate2 certificate)', validate parameter 'certificate' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

Do not call overridable methods in constructors (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2214)

In externally visible method 'X509AuthorityKeyIdentifierExtension.X509AuthorityKeyIdentifierExtension(AsnEncodedData encodedExtension, bool critical)', validate parameter 'encodedExtension' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

'string.IndexOf(char)' has a method overload that takes a 'StringComparison' parameter. Replace this call in 'Opc.Ua.Security.Certificates.AsnUtils.FromHexString(string)' with a call to 'string.IndexOf(char, System.StringComparison)' for clarity of intent. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1307)

'string.IndexOf(char)' has a method overload that takes a 'StringComparison' parameter. Replace this call in 'Opc.Ua.Security.Certificates.AsnUtils.FromHexString(string)' with a call to 'string.IndexOf(char, System.StringComparison)' for clarity of intent. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1307)

In externally visible method 'byte[] PEMWriter.ExportCertificateAsPEM(X509Certificate2 certificate)', validate parameter 'certificate' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)

In externally visible method 'X509CRL.X509CRL(IX509CRL crl)', validate parameter 'crl' is non-null before using it. If appropriate, throw an 'ArgumentNullException' when the argument is 'null'. (https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1062)