Blocking access to a former convicts records isn't enough. In a world of social media and google, a black hole in your resume of time while you were inside stands out.
An alternate solution might to give prisoners the ability to open access to their records. Yes, you committed crime X, but the records at the prison show that you kept your head down and did X qualifications.
The reason people don't hire prisoners is that it comes with risk. If we open up information, you can lower that risk.
Protected classes are typically things that people cant change about themselves, which largely doesn't apply to people who have been convicted of crimes.
It also has the downside of not allowing employers to avoid hiring people who have committed crimes in relation to their occupation. I might be fine hiring someone who embezzled as a software engineer, but I probably wouldn't hire them as my CFO.
An alternate solution might to give prisoners the ability to open access to their records. Yes, you committed crime X, but the records at the prison show that you kept your head down and did X qualifications.
The reason people don't hire prisoners is that it comes with risk. If we open up information, you can lower that risk.