European Union Agency for Network and Information Security (ENISA) says most protocols are hard to install in a secure fashion. ENISA says legacy systems should be updated ‘as a matter of urgency’ The second case depends on characteristics like proofs of security, key sizes of 128 bits of symmetric security or better, are well-studied and without structural weaknesses, are standardised, and have a reasonable existing installed base. It’s past time to plan the abandonment of legacy crypto, says ENISA.”]