[MobileAppController]
[RoutePrefix("api/register")]
[AllowAnonymous]
public class RegisterController : ApiController
{

    [HttpPost]
    [Route("newuser")]
    public HttpResponseMessage NewUser(RegistrationRequest request)
    {
        try
        {

            //...... code truncated for brevity

            myContext context = new myContext();
            DataObjects.Account account = context.Accounts.Where(a => a.Username == request.username).SingleOrDefault();

            if (account != null)
            {
                return Request.CreateResponse(HttpStatusCode.OK, new
                {
                    message = "That username already exists",
                    error = true
                });

            }
            else
            {
                    byte[] salt = CustomLoginProviderUtils.generateSalt();

                    DataObjects.Account newAccount = new DataObjects.Account()
                    {
                        Id = Guid.NewGuid().ToString(),
                        Username = request.username,
                        Salt = salt,
                        CreatedAt = DateTime.UtcNow,
                        SaltedAndHashedPassword = CustomLoginProviderUtils.hash(request.password, salt)
                    };
                    context.Accounts.Add(newAccount);
                    context.SaveChanges();

                return Request.CreateResponse(HttpStatusCode.OK, new
                {
                    message = "Account created successfully!",
                    error = false,
                    account = newAccount
                });
        }


        }catch(Exception ex)
        {
            // Retrieve the error messages as a list of strings.
            //var errorMessages = ex.EntityValidationErrors.SelectMany(x => x.ValidationErrors).Select(x => x.ErrorMessage);

            //// Join the list to a single string.
            //var fullErrorMessage = string.Join(";", errorMessages);

            //// Combine the original exception message with the new one.
            //var exceptionMessage = string.Concat(ex.Message, "The validation errors are:", fullErrorMessage);

            // Throw a new DbEntityValidationException with the improved exception message.
            //throw new DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);

            return Request.CreateResponse(HttpStatusCode.OK, new
            {
                message = "Failed!",
                error = true
            });
        }

public override int SaveChanges()
    {

        try
        {
            return base.SaveChanges();

        }catch (DbEntityValidationException ex)
        {
            // Retrieve the error messages as a list of strings.
            var errorMessages = ex.EntityValidationErrors.SelectMany(x => x.ValidationErrors).Select(x => x.ErrorMessage);

            // Join the list to a single string.
            var fullErrorMessage = string.Join(";", errorMessages);

            // Combine the original exception message with the new one.
            var exceptionMessage = string.Concat(ex.Message, "The validation errors are:", fullErrorMessage);

            // Throw a new DbEntityValidationException with the improved exception message.
            throw new DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);
        }
    }

**Generate Salt function**

 public static byte[] generateSalt()
    {
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        byte[] salt = new byte[256];
        rng.GetBytes(salt);
        //rng.GetNonZeroBytes(salt);
        return salt;
    }