Technically, the time stamp is an electronic signature that guarantees the existence of the cryptographic summary of a document at a given time. Therefore, its validity is subject to the validity of the certificate that produces it.

The AOC Consortium has an annual renewal policy for the certificates used to sign the time stamps we issue, to ensure that they are valid for a minimum of three years.
The following table shows the dates of issue, expiration and implementation of the various time-stamping certificates used by CATCert and the AOC Consortium since the start of the provision of the service:

Year Issue Expiration Installation at the TSA Certificate
2006 31/03/2006 31/03/2010 -
2009 03/08/2009 03/08/2013 10/15/2009 B9E59E25.zip
2011 10/03/2011 10/03/2015 24/03/2011 289C187B.zip
2011 12/12/2011 12/12/2015 03/2012 4FD9C341.zip
2012 11/20/2012 11/20/2016 28/12/2012 863EA7F7.zip
2013 12/11/2013 12/11/2017 20/12/2013 12DB0C1D.zip
2014 11/05/2014 11/05/2018 12/16/2014 6C66D133.zip
2015 10/22/2015 22/10/2019 4/11/2015 DB4FD4B9.zip
2016 13/10/2016 13/10/2020 11/16/2016 9FB7502F.zip
2017 15/09/2017 15/09/2021 11/09/2017 TSA_2017.zip
2018 27/07/2018 07/27/2022 03/10/2018 TSA_2018.zip
2019 16/07/2019 16/07/2023 25/07/2019 TSA_2019.zip
2020 01/07/2020 01/07/2024 22/09/2020 TSA_2020.zip
2021 21/06/2021 21/06/2025 21/07/2021 TSA_2021.zip