Program.cs

using System;
using System.IO;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml;
using System.Xml.Serialization;

namespace JereckNET.LicenseManager.Sample {
    class Program {
        public static void Main() {
#if     NETFRAMEWORK
            Console.WriteLine("Running as .NET Framework");
#elif   NETCOREAPP                                  
            Console.WriteLine("Running as .NET Core");
#endif
            Console.WriteLine();

            Console.WriteLine("**** Use case 1 ****");
            sample1();
            Console.WriteLine();

            Console.WriteLine("**** Use case 2 ****");
            sample2();
            Console.WriteLine();

            Console.WriteLine("**** Use case 3 ****");
            sample3();
            Console.WriteLine();

            Console.WriteLine("**** Use case 4 ****");
            sample4();
            Console.WriteLine();
        }

        /// <summary>
        /// Use case 1 : 
        ///     XML data
        ///     Signed with XML Public Key
        ///     Valid Signature
        ///     Saved as Base64
        ///     Read as byte[]
        /// </summary>
        private static void sample1() {
            bool status;
            License license;
            LicenseData data;

            Console.WriteLine("Loading \"License1.lic\" : ");
            license = License.Load(@"Licenses\License1.lic");
            status = license.Verify(Properties.Resources.LicensePublicKey);
            Console.WriteLine("Signature validity : " + status);

            if (status) {
                using (MemoryStream ms = new MemoryStream(license.Content)) {
                    using (XmlReader xr = XmlReader.Create(ms)) {
                        data = (LicenseData)new XmlSerializer(typeof(LicenseData)).Deserialize(xr);
                    }
                }

                Console.WriteLine("Product licensed to :");
                Console.WriteLine(data.ToString());
            }
        }

        /// <summary>
        /// Use case 2 : 
        ///     XML data
        ///     Signed with XML Public Key
        ///     Valid Signature
        ///     Saved as Base64
        ///     Read from <see cref="License.GetContentFromXML{T}"/>
        /// </summary>
        private static void sample2() {
            bool status;
            License license;
            LicenseData data;

            Console.WriteLine("Loading \"License1.lic\" : ");
            license = License.Load(@"Licenses\License1.lic");
            status = license.Verify(Properties.Resources.LicensePublicKey);
            Console.WriteLine("Signature validity : " + status);

            if (status) {
                data = license.GetContentFromXML<LicenseData>();

                Console.WriteLine("Product licensed to :");
                Console.WriteLine(data.ToString());
            }
        }

        /// <summary>
        /// Use case 3 : 
        ///     JSON data
        ///     Signed with PFX Private Key
        ///     Binary-encoded Public Key
        ///     Valid Signature
        ///     Saved as Base64
        ///     Read as string
        /// </summary>
        private static void sample3() {
            bool status;
            License license;

            Console.WriteLine("Loading \"License2.lic\" : ");
            license = License.Load(@"Licenses\License2.lic");
            using (X509Certificate2 certificate = new X509Certificate2(Properties.Resources.LicensePublicCertificateCRT)) {
                status = license.Verify(certificate);
            }

            Console.WriteLine("Signature validity : " + status);

            if (status) {

                string s = Encoding.UTF8.GetString(license.Content);

                Console.WriteLine("Product licensed to :");
                Console.WriteLine(s.ToString());
            }
        }

        /// <summary>
        /// Use case 4 : 
        ///     JSON data
        ///     Signed with PFX Private Key
        ///     Base64-encoded Public Key
        ///     Valid Signature
        ///     Saved as Base64
        ///     Read as string
        /// </summary>
        private static void sample4() {
            bool status;
            License license;

            Console.WriteLine("Loading \"License2.lic\" : ");
            license = License.Load(@"Licenses\License2.lic");

            byte[] CERData = fromBase64Certificate(Properties.Resources.LicensePublicCertificateCER);
            using (X509Certificate2 certificate = new X509Certificate2(CERData)) {
                status = license.Verify(certificate);
            }

            Console.WriteLine("Signature validity : " + status);

            if (status) {

                string s = Encoding.UTF8.GetString(license.Content);

                Console.WriteLine("Product licensed to :");
                Console.WriteLine(s.ToString());
            }
        }

        private static byte[] fromBase64Certificate(string content) {
            StringBuilder base64Content = new StringBuilder();

            using (StringReader sr = new StringReader(content)) {
                string currentLine = sr.ReadLine();

                if (currentLine.StartsWith("-")) // Skip "-----BEGIN CERTIFICATE-----" line
                    currentLine = sr.ReadLine();

                while (currentLine != null && !currentLine.StartsWith("-")) {  // Skip "-----END CERTIFICATE-----" line
                    base64Content.Append(currentLine);

                    currentLine = sr.ReadLine();
                }

                string base64License = base64Content.ToString();
                byte[] data = Convert.FromBase64String(base64License);

                return data;
            }
        }
    }
}