This 'insurance' is actually called so because it promises to ensure the employees that they amass money from their earnings towards a pension. The legal relation means that the person was in employment up to some point. Danny boyd's solution is good except that it does not really refer to any real insurance, but to the right to collect money to his own pension after retirement. My phrase also doesn't really sound perfect to me either, you could turn it a bit here and there, but this is the point.

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Note added at 3 hrs (2014-01-08 23:11:54 GMT)
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I mean, the original sentence doesn't really refer to an insurance ... (my sentence was also ambiguous, but I didn't mean that danny's sentence doesn't refer ... )

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Note added at 3 hrs (2014-01-08 23:25:25 GMT)
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One more remark as to why such ideas/words like "nyugdíjbiztosítás", or "nyugdíjbiztosító" have nothing to do with insurance. "biztosít" has another meaning, and that is "to provide", so these are only words about the possibility of provision of pension later. Perhaps that's why your sentence was in this sense difficult.