<PackageReference Include="System.Security.Cryptography.Cng" Version="5.0.0" />

System.Security.Cryptography.CngExportPolicies

public enum CngExportPolicies
Specifies the key export policies for a key.

The private key can be exported one time for archiving purposes.

The private key can be exported multiple times.

The private key can be exported one time as plaintext.

The private key can be exported multiple times as plaintext.

None = 0

No export policies are established. Key export is allowed without restriction.