web-app-template/backend/app/app.CredentialManager/Base64.cs

using System;

namespace app.CredentialManager
{
    public static class Base64
    {   
        public static string Encode(string credentials)
        {
            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(credentials);
            return System.Convert.ToBase64String(plainTextBytes);
        }

        public static string Decode(string credentials)
        {
            var base64EncodedBytes = System.Convert.FromBase64String(credentials);
            return System.Text.Encoding.UTF8.GetString(base64EncodedBytes);
        }

        public static string DecodeConnectionString(string connectionString, string credentials)
        {
            string decodedCredentials = Decode(credentials);
            return connectionString += $"password={decodedCredentials};";
        }
    }
}