String parameter in URL - MVC

Question

I am using a url to access another url, and then in case I use encoding in the parameter, when generating the URL is this way:

http://localhost:2021/Detalhe?Id=U2FsdGVkX18fELYzjpLDJ4AwrzMvAwGH82eXMHT9WnMMpkteqGdkWbilsrfWocqveHo5WxgrFdylwOq8fd/2Hg==

I’ve tried just like this

http://localhost:2021/Detalhe/IU2FsdGVkX18fELYzjpLDJ4AwrzMvAwGH82eXMHT9WnMMpkteqGdkWbilsrfWocqveHo5WxgrFdylwOq8fd/2Hg==

When I passed a value of type Guid, it worked perfectly, but now arose the necessity of the cryptography, it was like this:

@model Guid?
@{
    Layout = null;
}

and now I’ve switched to:

@model string
@{
    Layout = null;
}

But it comes empty, it can’t get the value of the URL, how can I do ? Thank you.