The development of cryptanalysis and the continuous development in computing capacities may make certain cryptographic algorithms obsolete. Thus, systems should regularly migrate to stronger and stronger cryptographic algorithms.

There has been a migration to stronger suits of cryptographic algorithms recently. Based on the update of the European specification on e-signature algorithms (ETSI TS 102 176), the Hungarian National Media and Communications Authority has issued a resolution that mandated certification service providers to cease the use of certain cryptographic algorithms (including the SHA-1 hash function) from the 1^st of January, 2012.

In our paper we summarize some lessons learned from this migration, and we analyze whether the transition was successful and smooth in Hungarian e-signature systems.