<story><title>Airline keeps mistaking 101-year-old woman for 1-year-old baby</title><url>https://www.bbc.com/news/articles/c9wz7pvvjypo</url></story><parent_chain><item><author>TazeTSchnitzel</author><text>Dates in passports&amp;#x27; machine-readable zones only have two-digit years. Another victim: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;theguardian.com&amp;#x2F;uk-news&amp;#x2F;2020&amp;#x2F;feb&amp;#x2F;12&amp;#x2F;home-office-tells-man-101-his-parents-must-confirm-id&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;theguardian.com&amp;#x2F;uk-news&amp;#x2F;2020&amp;#x2F;feb&amp;#x2F;12&amp;#x2F;home-office-tell...&lt;/a&gt;.</text></item></parent_chain><comment><author>miki123211</author><text>The Polish PESEL system, which encodes your birth date in your national identification number, found a nice way around this. We just add 20 to your &lt;i&gt;birth month&lt;/i&gt; if you were born in the 21st century or 80 if you were born in the 19th. This exploits the fact that a month is always in the range 1-12, and so using a two-digit number for it wastes a large part of the possible space of dates.&lt;p&gt;We still have the 41-52 and 61-72 ranges unused for the 22rd and 23rd centuries, and then we can re-use 80 (since it&amp;#x27;s extremely unlikely for anybody from the 19th century to survive that long). Now that&amp;#x27;s some long-term planning.&lt;p&gt;However, it&amp;#x27;s often said that no plan survives contact with reality, and that&amp;#x27;s also unfortunately true for this system. All that future proofing, and now it turns out that some assumptions thought inviolable, namely that people are either strictly male or strictly female and never change their gender, aren&amp;#x27;t so inviolable after all. We use a single bit to encode gender (it&amp;#x27;s the evenness or oddness of a particular digit in the number), and we also assume that PESEL numbers never change, to the point of using them as primary keys in some databases. The latter is causing trouble right now, and the former is inevitably going to.</text></comment>
<story><title>Airline keeps mistaking 101-year-old woman for 1-year-old baby</title><url>https://www.bbc.com/news/articles/c9wz7pvvjypo</url></story><parent_chain><item><author>TazeTSchnitzel</author><text>Dates in passports&amp;#x27; machine-readable zones only have two-digit years. Another victim: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;theguardian.com&amp;#x2F;uk-news&amp;#x2F;2020&amp;#x2F;feb&amp;#x2F;12&amp;#x2F;home-office-tells-man-101-his-parents-must-confirm-id&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;theguardian.com&amp;#x2F;uk-news&amp;#x2F;2020&amp;#x2F;feb&amp;#x2F;12&amp;#x2F;home-office-tell...&lt;/a&gt;.</text></item></parent_chain><comment><author>cedilla</author><text>I was about to write that surely, that only applies to the OCR section printed on the physical passport, but if I read ICAO 9303 correctly, it&amp;#x27;s the other way round - the OCR section can include either a four-digit year or a two-digit year, but the chip has only six bytes for the date of birth, representing YYMMDD in digits (plus special characters for an unknown or partially known date of birth).&lt;p&gt;Edit: apparently there&amp;#x27;s an optional section in the chip (data group 11 or DG11) that allows for longer-form data than the ancient machine-readable format, including non-latin letters in the name and a birthdate including the century. I don&amp;#x27;t know how widely used that is though.</text></comment>